1 2 3 4 Previous Next 133 Replies Latest reply: Jul 2, 2009 3:14 PM by Rick McCleary RSS

    Assign Profile vs Converting to Profile

    Printer_Rick Community Member

      This relates to a very lengthy thread in the InDesign forum, "RGB vs CMYK images and resolution"

       

      I have a lot of questions (perhaps confusing) relating to RGB color gamuts. To simplify let's start with 2 gamuts, ProPhoto and Adobe RGB

       

      I have a profile editor that can view both of these within potato-shaped Lab gamut. They are of course both triangles, I believe all RGB gamuts are. I can see ProPhoto is considerably larger than Adobe RGB, containing more fringe colors

       

      I also see that the gamma of Adobe RGB is 2.2. The white point is 6500K

       

      The gamma of ProPhoto is 1.8. The white point is 5000K

       

      I understand gamma to be "black point". Or better yet "black density". On a press sheet, ink density can be measured with a densitometer. In my experience a density reading of 2.2 on a press sheet would be very dark. Is my understanding correct - that gamma (RGB) is comparable to ink density (CMYK)? Perhaps better to state as an analogy: Gamma: RGB as Density: CMYK

       

      My monitor RGB profile has a gamma of 1.8 (mac standard). This tells me that the Adobe RGB gamma of 2.2 has to be re-interpreted on my display. Is that correct?

       

      As for white point, that would be the RGB equivalent of CMYK paper white.

       

      The InDesign forum has a lot of discussion about assigning profiles, vs converting to profiles. My understanding is that assigning a different RGB is actually a "pure" conversion. The pixels are left completely intact. There is no move to Lab, and back to RGB. It's taking the image and effectively dropping it into a brand new gamut, The price for this, of course, is that the appearances of the colors are completely redefined, and this appearance shift can at times be radical.

       

      For example, if I have an ProPhoto image open, then assign Adobe RGB, I can see very clearly that the image becomes darker on-screen, and the color "shrinks"

       

      As a prepress person, I have often used re-assigning in RGB mode as a very effective color correction tool. Usually it's turd polishing, to be quite honest, when critical color match is not an issue. The scenario is usually a crappy sRGB image. I assign Adobe RGB, which as the Adobe description states is ideal for conversion to CMYK. I must add that I always use proof preview, I am well aware that Adobe RGB has colors far beyond a standard CMYK gamut. But when I convert to CMYK, using Adobe RGB as the source, the image color is expanded, and the result on press is often vastly improved.

       

      I will also add that as a prepress person, I don't go re-assigning in this fashion without the customer's consent.

       

      In the InDesign forum, this "re-assigning" has been referred to as "random color". There is a lot of emphasis on color appearance, and maintaining color appearance. The consensus therefore is that if you had an sRGB image, you should convert to Adobe RGB. But then it is my understanding that you miss out on the often huge benefit of gamut expansion. If you wanted to expand color after converting, you have to do color corrections, which alters the pixel data and in the strictest sense is destructive (unless you use adjustment layers).

       

      All this leaves me wondering - if assigning is such a no-no, why is it available? Probably the main reason for the assign capability is to assign profiles to images that don't have an embedded profile. Sometimes users unknowingly discard profiles, if the color settings policy is set to off. When another user open the image, he quickly sees the image does not have a profile.

       

      Normally he would assign his working space, since that is affecting his visual on-screen appearance. But he can't know for sure if that's true to the original capture.

       

      Which brings up another point. Any device doing the capture (camera or scanner) has a gamut. This gamut is an input profile.  When the image is translated from device capture into digital file, should this input profile be embedded in the image?

       

      At this point I'm not sure about this. I have a 7.1 MP camera, and the downloads always have sRGB embedded. Not a profile specific to the Kodak model. My guess is that sRGB is a universal standard, representing the gamuts of monitors and desktop scanners. It is the working space of the world wide web. So it's more or less the default RGB, and is also the default working space in all Adobe applications (North America general purpose).

       

      But the description of sRGB is very clear. It is not ideal for prepress, this is stated in Adobe's description. It is small. This may make it comparable to CMYK, but it is still not ideal for conversion to CMYK. And in fact there are CMYK colors that fall outside of sRGB. Especially if you are dealing with the larger CMYK gamuts corresponding to new offset screening technologies (FM screening and concentric screening)

       

      So why in the world would someone convert from sRGB, to Adobe RGB? There's no benefit at all. May as well leave it sRGB, instead of converting. And the even bigger question - how do you know that sRGB is "true" color? To me, the true color is the original subject. In the case of a photo, that might be just a memory. In the case of a scan. it's the original, but the user might not even have that, if someone else did the scan and all he has is the digital file. So who's to say that the embedded profile - sRGB - is a fair representation of the original?

       

      Re-assigning RGB profiles may be an odd way of adjusting color. But it can be effective. Why would the assign option be readily available, if not to translate colors to a different gamut, without altering pixel data? Seems to me it is the primary reason Adobe developed the assign option in the first place.

       

      I know this is a lot of questions. Any input on any of these matters would be greatly appreciated.

        • 1. Re: Assign Profile vs Converting to Profile
          Ramón G Castañeda Community Member

          Try again, posting only one question per post, as concisely as you can.

          • 2. Re: Assign Profile vs Converting to Profile
            Ramón G Castañeda Community Member

            I don't think your post is going to find many users here willing to read it in its entirety, and even less who will attempt to answer it.

             

            You make an awful lot of wrong assumptions, a lot of irrelevant ones, and many unnecessary ones.

             

            Start learning about Color Mangaement here:

             

            http://www.gballard.net/psd/cmstheory.html

             

            In the next post, I'll explain the difference betwen Assigning and Converting to you.

            • 3. Re: Assign Profile vs Converting to Profile
              Ramón G Castañeda Community Member

              This excerpt copied and pasted from an old post of mine may help you understand the difference between CONVERT and assign.

              To understand profiles, think of your image as text, and of the profile as a tag that indicates in which language the text is written.

              If you see text that says GIFT, you need to know whether it's in English or in German. If in German, the word means "poison", if in English, it means a present.

              Other examples: ONCE means "eleven" in Spanish but "one time" in English.

              MOST means "Bridge" in Russian but "greatest in amount, extent, or degree" in English and "fruit juice" in German.

              If you change the language (profile) by ASSIGNING, you change the meaning of the text (appearance of the image). The numbers representing the colors in your image will remain the same, but the colors will change because the same numbers now mean something else (as the meaning of the text will change if you now read the same letters in a different language).

              CONVERTING to a profile will preserve the colors while the numbers change, in the same manner as the text will retain its meaning if you TRANSLATE it into a different language, changing the letters but preserving the meaning.

               

              Bottom line:

               

              ASSIGNing a different profile will preserve the numbers and will change the colors of the image;

               

              CONVERTing to a profile will preserve the colors and change the numbers accordingly.

              • 4. Re: Assign Profile vs Converting to Profile
                Ramón G Castañeda Community Member

                Printer_Rick wrote:


                …My monitor RGB profile has a gamma of 1.8 (mac standard).

                 

                You are living in the stone age.  Gamma 1.8 is a relic left over from the day of monochrome monitors and black-and-white LaserWriter printers.  It has nothing to do with colors.  Pros have been using gamma 2.2 for years and years.  Even Apple recommends it.

                 

                As a matter of fact, the default value in the upcoming Leopard (OS 10.6) due in September will in fact be gamma 2.2.

                • 5. Re: Assign Profile vs Converting to Profile
                  Ramón G Castañeda Community Member

                  Printer_Rick wrote:

                   

                  They are of course both triangles, I believe all RGB gamuts are.

                   

                  WRONG.  Profiles are complex three-dimensional bodies in space.  You're looking at a simplified 2-dimensional projection on a single plane that tells you very little.

                   

                  Printer_Rick wrote:

                   

                  I have a profile editor that can view both of these …

                   

                  My suggestion would be to put it away for now, until you have learned a bit more about color theory and color management.  Now it's just confusing you—massively, apparently.

                   

                  (Sorry if you are in fact a printer by profession, as your user ID suggests.  I don't mean to offend you, but you need to do a lot of studying.)

                   

                  As a matter of fact, I'll stop right here.  I can see it would take way more time than I have to read the rest of your post and straighten out your misconceptions.

                   

                  PS— sRGB is the lowest common denominator, where the "s" stands for sh¡t.

                  • 6. Re: Color Management forum
                    Ramón G Castañeda Community Member

                    Finally, you should know that there is a dedicated Color Management forum in these Adobe forums, and that's where this type of discussions belongs—not here, really.

                     

                    http://forums.adobe.com/community/design_development/color_management#

                    • 7. Re: Assign Profile vs Converting to Profile
                      Printer_Rick Community Member

                      Ramon,

                       

                      Sorry for the lengthy initial post. I appreciate your response. I know it is a lot of questions. I'm not sure what you mean by irrelevant assumptions.

                       

                      I'm not new to color management, and I am aware of color theory. And I understand the difference between assign and convert. Assign preserves numbers, convert attempts to preserve appearance

                       

                      I will restate as 3 concise questions in separate posts.

                      • 8. Re: Assign Profile vs Converting to Profile
                        Miguel Curto Community Member

                        Adobe RGB  and Kodak Pro Photo RGB are large gamut (PRoPhoto being one of the largest) device Indepedent profiles (sRGB is too).

                        sRGB is a narrow gamut profile intended to try to reproduce an uncalibrated monitor and atenuate diferences from the same image shown in diferent monitors.

                         

                        All CMYK are a device dependent profiles that determine a print intention.As a usefull exercice go to Edit - > Color Settings -> CMYK and choose "Custom CMYK" so you can see what in fact a CMYK profile is.

                         

                        Being new to this forums dont know if I can do this,but I would recomend you read late Bruce Fraser book "Real World Photoshop" focused on Color Management or at least read some of his articles at Creativepro:

                         

                        http://www.creativepro.com/articles/author/127446

                        • 9. Re: Assign Profile vs Converting to Profile
                          Ramón G Castañeda Community Member

                          Printer_Rick wrote:

                           

                          Why would the assign option be readily available, if not to translate colors to a different gamut, without altering pixel data? Seems to me it is the primary reason Adobe developed the assign option in the first place.

                           

                          Gawd, that's so wrong that I hardly know where to begin.

                           

                          Let's see…

                           

                          ASSIGN is there so you can make educated guesses as to what color space an untagged file was created handed to you by a moron.  When you run into such a moron who does not embed the profile in his images, first cycle through possible color profiles in the ASSIGN dialog box until you make and educated guess by finding the one profile that makes the image look most plausible, then go beat up the moron who handed you that file with a baseball bat.

                           

                          No, Adobe, didn't develop ASSIGN so you could wreck images willy-nilly.

                           

                          Now, I'll stop.  My blood pressure is ggoing through the roof already.

                          • 10. Re: Assign Profile vs Converting to Profile
                            Ramón G Castañeda Community Member

                            Printer_Rick wrote:

                             

                            I'm not new to color management, and I am aware of color theory.

                             

                            Then you're…

                            • 11. Re: Assign Profile vs Converting to Profile
                              Printer_Rick Community Member

                               

                               

                              WRONG.  Profiles are complex three-dimensional bodies in space.  You're looking at a simplified 2-dimensional projection on a single plane that tells you very little.

                               

                               

                               

                              I am aware color is 3 dimensional, wasn't trying to imply it wasn't. RGB is displayed as a triangle in simple models, that's what I was getting at

                               

                               

                               

                              PS— sRGB is the lowest common denominator, where the "s" stands for sh¡t.

                               

                              sRGB is not my working RGB space

                               

                              Finally, you should know that there is a dedicated Color Management forum in these Adobe forums, and that's where this type of discussions belong—not here, really.

                               

                              Then I will post my questions there. Again my apologies.

                              • 12. Please post in the Color Management forum
                                Ramón G Castañeda Community Member

                                Printer_Rick wrote:

                                 

                                I will restate as 3 concise questions in separate posts.

                                 

                                Not here, please.


                                Post in the Color Management forum, where this discussion belongs.

                                • 13. Re: Assign Profile vs Converting to Profile
                                  Ramón G Castañeda Community Member

                                  Miguel Curto wrote:

                                   

                                  Being new to this forums dont know if I can do this,

                                   

                                  Absolutely, Miguel.  We link to books and web sites all the time.

                                   

                                  Welcome to the forums!  

                                  • 14. Re: Assign Profile vs Converting to Profile
                                    Printer_Rick Community Member

                                    Miguel,

                                     

                                    Thanks for the response I will look into it.

                                    • 15. Re: Assign Profile vs Converting to Profile
                                      Printer_Rick Community Member

                                       

                                      No, Adobe, didn't develop ASSIGN so you could wreck images willy-nilly.

                                       

                                       

                                       

                                      That's fine if you see assigning as wrecking images. It works for me, I've done it with good results.

                                      • 17. Re: Assign Profile vs Converting to Profile
                                        Miguel Curto Community Member

                                        Assign profile is there for you to assign IF the image comes with no embedded profile.Period.

                                         

                                        EDIT:Thats the closest thing you'll find to cheats on Photoshop.Why would you want to brake something that works well?

                                        Give a look on those articles...they are very well writen and clear.

                                         

                                        Either that or youre writing an article about Color Management and want to demonstrate something on screen.

                                        • 18. Re: Color Management forum
                                          Printer_Rick Community Member

                                           

                                           

                                          Finally, you should know that there is a dedicated Color Management forum in these Adobe forums, and that's where this type of discussions belongs—not here, really.

                                           


                                           

                                          My color management questions were related to images and therefore Photoshop. On another note, if it doesn't belong, why did you reply more than 10 times? You could have ignored my post.

                                           

                                          As a matter of fact, the default value in the upcoming Leopard (OS 10.6) due in September will in fact be gamma 2.2.

                                          So what you're saying is, 2.2 is not currently the default. So what is the current mac default? I wonder...

                                           

                                          ASSIGN is there so you can make educated guesses as to what color space an untagged file was created handed to you by a moron.  When you run into such a moron who does not embed the profile in his images, first cycle through possible color profiles in the ASSIGN dialog box until you make and educated guess by finding the one profile that makes the image look most plausible, then go beat up the moron who handed you that file with a baseball bat.

                                          And what if a moron unwittingly embedded the wrong profile in output? Then assigning a different one would restore the original color.

                                           

                                          PS— sRGB is the lowest common denominator, where the "s" stands for sh¡t.

                                           

                                           

                                          sRGB is Adobe's default RGB color space. It is the standard for world wide web. It is used by Pantone. In short it is the RGB profile most commonly encountered

                                           

                                          I will re-iterate it's not my working RGB space, I don't care for it, I don't consider it ideal for CMYK conversion.

                                          • 19. Re: Color Management forum
                                            Miguel Curto Community Member

                                            Printer_Rick wrote:

                                             

                                             

                                            sRGB is Adobe's default RGB color space. It is the standard for world wide web. It is used by Pantone. In short it is the RGB profile most commonly encountered

                                             

                                            I will re-iterate it's not my working RGB space, I don't care for it, I don't consider it ideal for CMYK conversion.

                                             

                                            The idea that sRGB is the most common profile is a misconception.That profile was created to simulate an uncalibrated enviroment (monitor).Thats why if you use Photoshop function "Save for Web" it converts to sRGB then strips profile information.And this is only because until recently most web browsers didnt have any Color Management.I know Firefox has but the others until recently didnt (might be diferent know thought).

                                             

                                            If its used by Pantone or not I dont know,but if it is I would like to know why and for what purpose cause it doesnt make any sense...

                                             

                                            Its not ideal for any print (CMYK convertion) since it's very narrow gamut will most probably clip many satured colors.

                                             

                                            The only good thing about it (besides being a grey balanced profile) is that you can be sure the person you send it too will not see many variations (shifts) in color from what youre seing on your calibrated monitor using Photoshop or any other ICC aware aplication.Thats why I always send previews of work in sRGB, because most of the time people that have to evaluate it dont even bother to open them in Photoshop,they use e-mail programs or browsers,let alone calibrated/profiled monitors.

                                             

                                            I think the idea behind making it default is just that,being on the safe side.People that are aware of that ussually change it unless theyre working mainly for the Web.

                                             

                                            This and much more you can find on the links about Bruce Fraser.He made great contributions to make people aware of Color Management.

                                             

                                            Hope this helps.

                                             

                                            Especificaly u can read this one:

                                             

                                            http://www.creativepro.com/article/out-of-gamut-getting-a-handle-on-color-management

                                             

                                            Images on examples are self-explanatory.

                                            • 20. Re: Color Management forum
                                              Printer_Rick Community Member

                                              Thanks for the input

                                               

                                              When saying sRGB is the most common profile, I meant it's the one I see most. My RGB policy is set to preserve embedded. The VAST majority of images I receive from clients use this profile. My thinking is most designers do not change the default color settings (North America general purpose)

                                               

                                              Usually when I open these sRGB images, reassign Adobe RGB, then convert to CMYK, the result is much better than sRGB - CMYK. If my RGB policy was set to Off, I would get the same effect as re-assigning - my working space is Adobe RGB.

                                               

                                              I'll add I only throw out the embedded sRGB if the the customer requests pleasing color, and the proof preview is crud. Otherwise I have to honor the sRGB.

                                              • 21. Re: Color Management forum
                                                Miguel Curto Community Member

                                                Printer_Rick wrote:

                                                 

                                                 

                                                When saying sRGB is the most common profile, I meant it's the one I see most. My RGB policy is set to preserve embedded. The VAST majority of images I receive from clients use this profile. My thinking is most designers do not change the default color settings (North America general purpose)

                                                 

                                                Usually when I open these sRGB images, reassign Adobe RGB, then convert to CMYK, the result is much better than sRGB - CMYK. If my RGB policy was set to Off, I would get the same effect as re-assigning - my working space is Adobe RGB.

                                                 

                                                I'll add I only throw out the embedded sRGB if the the customer requests pleasing color, and the proof preview is crud. Otherwise I have to honor the sRGB.

                                                 

                                                http://www.creativepro.com/files/story_images/Fig_1.jpg

                                                 

                                                To make this example I would have one patch of color (in Adobe RGB or even sRGB)and dulicate it 3 times.Then would leave original alone and CONVERT the others to Scanner,Monitor and Printer Profiles.But in Photoshop they all look alike (like this one bellow):

                                                 

                                                http://www.creativepro.com/files/story_images/Fig_2.jpg

                                                 

                                                 

                                                To publish this example (in Fig1) I would have to "break" Color Management and "assign to sRGB" all of them so you could actually see the diference how that particular value of RGB is renderer in those diferent devices.

                                                 

                                                The reason your convertion is working is probably beacuse most of the times you receive the images over-saturated...which yelds bad results in straight conversion to CMYK because off out-of-gamut colors (altought you can try Perceptual renderings if you have many diferent colors).When you assign sRGB values to Adobe RGB youre actually (among other things) de-saturating de images.

                                                • 22. Re: Assign Profile vs Converting to Profile
                                                  Printer_Rick Community Member

                                                  Ramón G Castañeda wrote:


                                                  To understand profiles, think of your image as text, and of the profile as a tag that indicates in which language the text is written.

                                                  If you see text that says GIFT, you need to know whether it's in English or in German. If in German, the word means "poison", if in English, it means a present.

                                                  Other examples: ONCE means "eleven" in Spanish but "one time" in English.

                                                  MOST means "Bridge" in Russian but "greatest in amount, extent, or degree" in English and "fruit juice" in German.

                                                  If you change the language (profile) by ASSIGNING, you change the meaning of the text (appearance of the image). The numbers representing the colors in your image will remain the same, but the colors will change because the same numbers now mean something else (as the meaning of the text will change if you now read the same letters in a different language).

                                                  CONVERTING to a profile will preserve the colors while the numbers change, in the same manner as the text will retain its meaning if you TRANSLATE it into a different language, changing the letters but preserving the meaning.

                                                   

                                                  Bottom line:

                                                   

                                                  ASSIGNing a different profile will preserve the numbers and will change the colors of the image;

                                                   

                                                  CONVERTing to a profile will preserve the colors and change the numbers accordingly.

                                                  Not true, the language analogy falls short. You are suggesting that assigning Adobe RGB to an sRGB image may turn greens to reds, and blues to yellows. And that is not what happens at all.

                                                   

                                                  Words have negative (poison) and positive (gift) values. But there are no "good" or "bad" colors.

                                                   

                                                  And what would Lab be in the language scenario? It's not as if there is a universal language that everyone uses to translate (convert). But there is a universal color space everyone uses to convert.

                                                   

                                                  Furthermore converting does not preserve appearance, it attempts to preserve appearance. Which is not possible when going from a large gamut to a smaller one.

                                                  • 23. Re: Color Management forum
                                                    Was DYP Community Member

                                                    Usually when I open these sRGB images, reassign Adobe RGB, then convert to CMYK, the result is much better than sRGB - CMYK. If my RGB policy was set to Off, I would get the same effect as re-assigning - my working space is Adobe RGB.

                                                     

                                                    I'll add I only throw out the embedded sRGB if the the customer requests pleasing color, and the proof preview is crud. Otherwise I have to honor the sRGB.

                                                     

                                                    I know exactly what you are talking about, and there is no reason not to use this approach if you achieve the desired result by doing so. I have many timed re-assigned (I like this name much better than false profile) an image in Adobe RGB to some other RGB space like Ekta Space or others to achieve the desired look when converting to CMYK. It is no more of a trick than to make image adjustments for the same reasons.

                                                    • 24. Re: Color Management forum
                                                      Printer_Rick Community Member

                                                      Miguel Curto wrote:

                                                       

                                                       

                                                      To make this example I would have one patch of color (in Adobe RGB or even sRGB)and dulicate it 3 times.Then would leave original alone and CONVERT the others to Scanner,Monitor and Printer Profiles.But in Photoshop they all look alike (like this one bellow):

                                                       

                                                       

                                                      I already know that conversion in these cases preserves on-screen appearance.

                                                       

                                                      The reason your convertion is working is probably beacuse most of the times you receive the images over-saturated...which yelds bad results in straight conversion to CMYK because off out-of-gamut colors (altought you can try Perceptual renderings if you have many diferent colors).When you assign sRGB values to Adobe RGB youre actually (among other things) de-saturating de images.

                                                      No, the opposite. I receive the sRGB. Assign Adobe RGB. Color is expanded.

                                                      • 25. Re: Assign Profile vs Converting to Profile
                                                        Printer_Rick Community Member

                                                        Was DYP wrote:

                                                         

                                                         

                                                        I know exactly what you are talking about, and there is no reason not to use this approach if you achieve the desired result by doing so. I have many timed re-assigned (I like this name much better than false profile) an image in Adobe RGB to some other RGB space like Ekta Space or others to achieve the desired look when converting to CMYK. It is no more of a trick than to make image adjustments for the same reasons.

                                                         

                                                        Finally! Someone knows where I'm coming from. It's a simple concept. Why is this process hated so much? As long as you proof and like the results, re-assigning is effective.

                                                        • 26. Re: Color Management forum
                                                          Printer_Rick Community Member

                                                          My original post had valid questions. I was searching for valid answers. I was not trying to suggest how someone should set up a color management workflow.

                                                           

                                                          Why have I angered you so much? That was not my intent. If you have insight, you can share it without including insults or personal attacks.

                                                          • 27. Re: Color Management forum
                                                            Miguel Curto Community Member

                                                            Printer_Rick wrote:

                                                             


                                                            No, the opposite. I receive the sRGB. Assign Adobe RGB. Color is expanded.

                                                             

                                                            Actually no.Since Adobe RGB is much larger than sRGB if youre assigning sRGB values to Adobe RGB you end up"with lots of free space".

                                                             

                                                            PS- Im not hangered in any way... this is a "healthy" discussion...the objective of this forums I think.We dont have to agree but many people come here and they should get facts straight...

                                                            • 28. Re: Color Management forum
                                                              PeterK.. Community Member

                                                              Printer_Rick wrote:

                                                               

                                                              No, the opposite. I receive the sRGB. Assign Adobe RGB. Color is expanded.

                                                               

                                                              You're screwing up your client's intended colour. They viewed it as sRGB, saved it with sRGB because that's the final image they settled on, and then you just arbitrarily decide to assign AdobeRGB and convert to CMYK? Let me guess... then the client complains that the colour is off and you charge them for "edits."

                                                              It's just a bad workflow. If the client's file is not coming out on press as it looks on screen, you need to profile your press better so that you can convert the client's RGB to your CMYK and have it match. Assigning a different profile because it suits your subjective taste is ridiculous.

                                                              (besides, skin tones often take on an ugly reddish tone by incorrectly assigning AdobeRGB to a sRGB image.)

                                                              If I send you a sRGB file, that is how I viewed it in Photoshop, how I saved it, and how I expect it to look. Even for a client that request "pleasing" colour, if they're sending you a sRGB the assumption is the same. They approved that image and sent it out the door like that, so for what reason are you screwing with their intended colour from the outset?

                                                              • 29. Re: Color Management forum
                                                                Ramón G Castañeda Community Member

                                                                It's useless, Miguel.  Anyone with an IQ above room temperature and a modicum of understanding of color theory can easily spot the blatant fallacies this [edited by host]  guy keeps coming up with, post after post.  I've now plonked him, so I don't even see his posts at all.

                                                                • 30. Re: Color Management forum
                                                                  Miguel Curto Community Member

                                                                  Ramón G Castañeda wrote:

                                                                   

                                                                  It's useless, Miguel.  Anyone with an IQ above room temperature and a modicum of understanding of color theory can easily spot the blatant fallacies this guy keeps coming up, post after post.  I've now plonked him, so I don't even see his posts at all.

                                                                  Im not on a mission,but this is the kind of things im used to discuss with my clients whenever they demand work delivered in CMYK.So its kind of a personal thing to desmistify some of this miths.

                                                                   

                                                                  No harm or agravation intended.It was only half a dozen years back when I read that book I mentioned I got a full perspective on Color Management.

                                                                  • 31. Re: Color Management forum
                                                                    Printer_Rick Community Member

                                                                    Miguel Curto wrote:

                                                                     

                                                                    Actually no.Since Adobe RGB is much larger than sRGB if youre assigning sRGB values to Adobe RGB you end up"with lots of free space".

                                                                     

                                                                    PS- Im not hangered in any way... this is a "healthy" discussion...the objective of this forums I think.We dont have to agree but many people come here and they should get facts straight...

                                                                     

                                                                    Thanks for that Miguel, I appreciate it. I did not post my original questions to anger anyone

                                                                     

                                                                    I should clarify. I receive an sRGB image. I assign Adobe RGB. On-screen the color is more saturated. This saturation carries over into the subsequent CMYK conversion.

                                                                     

                                                                    Try it with any sRGB image. Convert to CMYK, save a copy. Then assign Adobe RGB, convert to CMYK. Compare the two CMYK images, I think you'll see what I mean.

                                                                     

                                                                    It is not a specific color correction by any stretch, but it's not random rearranging of colors either.

                                                                    • 32. Re: Color Management forum
                                                                      Printer_Rick Community Member

                                                                      PeterK.. wrote:

                                                                       

                                                                      You're screwing up your client's intended colour. They viewed it as sRGB, saved it with sRGB because that's the final image they settled on, and then you just arbitrarily decide to assign AdobeRGB and convert to CMYK? Let me guess... then the client complains that the colour is off and you charge them for "edits."

                                                                      It's just a bad workflow. If the client's file is not coming out on press as it looks on screen, you need to profile your press better so that you can convert the client's RGB to your CMYK and have it match. Assigning a different profile because it suits your subjective taste is ridiculous.

                                                                      (besides, skin tones often take on an ugly reddish tone by incorrectly assigning AdobeRGB to a sRGB image.)

                                                                      If I send you a sRGB file, that is how I viewed it in Photoshop, how I saved it, and how I expect it to look. Even for a client that request "pleasing" colour, if they're sending you a sRGB the assumption is the same. They approved that image and sent it out the door like that, so for what reason are you screwing with their intended colour from the outset?

                                                                      Peter I think you've misunderstood me. It's not my workflow, not by any stretch. I only do it when a client requests color correction. Otherwise I always honor the sRGB as source.

                                                                       

                                                                      I was just suggesting this for a really bad colorless sRGB image, as a quick fix, that's all.

                                                                      • 33. Re: Color Management forum
                                                                        Was DYP Community Member

                                                                        I did not post my original questions to anger anyone

                                                                         

                                                                        Most of us have angered Ramón over the years. It is very easy to do to [his: edited by host] way of thinking.

                                                                         

                                                                        Count that as a badge of honor! Most of us have already earned that.

                                                                         

                                                                        "I've now plonked him, so I don't even see his posts at all."  - He has done that to me and I am so thankful. It is just that he does not always keep his promises.

                                                                        • 34. Re: Assign Profile vs Converting to Profile
                                                                          Printer_Rick Community Member

                                                                          Thanks for that. Maybe you can help with this question, I posted earlier in color management (at Ramón's suggestion):

                                                                           

                                                                          "Should input RGB device profiles (camera, scanner) be embedded and used as a source space, for conversion to CMYK? Or converted to another RGB space (such as Adobe RGB), then converted to CMYK? I don't see where 2 conversions are beneficial, but I could be wrong..."

                                                                           

                                                                          The main reason I ask this is, I very rarely see RGB images with scanner and camera profiles embedded. To be honest most I receive are sRGB, or don't have a profile at all.

                                                                           

                                                                          Not being a photographer, I don't download camera images for correction in Photoshop. My scanner produces a LAB image (I work in Linocolor when scanning), so no RGB profile there either.

                                                                          • 35. Re: Color Management forum
                                                                            Miguel Curto Community Member

                                                                            Printer_Rick wrote:

                                                                             


                                                                            Thanks for that Miguel, I appreciate it. I did not post my original questions to anger anyone

                                                                             

                                                                            I should clarify. I receive an sRGB image. I assign Adobe RGB. On-screen the color is more saturated. This saturation carries over into the subsequent CMYK conversion.

                                                                             

                                                                            Try it with any sRGB image. Convert to CMYK, save a copy. Then assign Adobe RGB, convert to CMYK. Compare the two CMYK images, I think you'll see what I mean.

                                                                             

                                                                            It is not a specific color correction by any stretch, but it's not random rearranging of colors either.

                                                                             

                                                                            Youre partially right,I does look more satured,I made a mistake assuming it would be the other way around but I can see whats happening.I know why but it would be really hard for me to explain...its the values in between that disapear (or not represented by Photoshop) and not the extremes...not more color but more gradient if you get my meaning)

                                                                             

                                                                            on the other hand can I suggest you something?:

                                                                             

                                                                            Save those both images (original sRGB and the other you assign to AdobeRGB) and save them both (as JPGs for instance).

                                                                            Now open both in a non ICC aware aplication (Internet Explorer will do just fine).Can you spot the diference?

                                                                            • 36. Re: Color Management forum
                                                                              Printer_Rick Community Member

                                                                              Miguel Curto wrote:

                                                                               

                                                                              Youre partially right,I does look more satured,I made a mistake assuming it would be the other way around but I can see whats happening.I know why but it would be really hard for me to explain...on the other hand can I suggest you something?:

                                                                               

                                                                              Save those both images (original sRGB and the other you assign to AdobeRGB) and save them both (as JPGs for instance).

                                                                              Now open both in a non ICC aware aplication (Internet Explorer will do just fine).Can you spot the diference?

                                                                              I don't have Explorer on my mac. Safari showed a difference. Preview showed a difference. Quick Time did not.

                                                                               

                                                                              Apparently Quick Time just defaults to monitor as source. So it must be what you refer to as non ICC aware app.

                                                                               

                                                                              I think the reason (correct me if I'm wrong) that assigning Adobe RGB expands the color is because the number values take on a new definition in the larger gamut.

                                                                               

                                                                              By the way, how can 1.8 gamma be considered stone age? Would 2.2 give a better CMYK preview?

                                                                              • 37. Re: Assign Profile vs Converting to Profile
                                                                                Was DYP Community Member

                                                                                "Should input RGB device profiles (camera, scanner) be embedded and used as a source space, for conversion to CMYK? Or converted to another RGB space (such as Adobe RGB), then converted to CMYK? I don't see where 2 conversions are beneficial, but I could be wrong..."

                                                                                 

                                                                                If you are going to do anything (adjustments) to a photo you will want to convert to a working profile space. If no adjustments are needed you could certainly convert to CMYK from the device profile. But again like re-assigning, what ever works best for your desired finish result. But certainly do not save an image with any chance to passed along with device profiles embedded.

                                                                                • 38. Re: Color Management forum
                                                                                  Was DYP Community Member

                                                                                  Save those both images (original sRGB and the other you assign to AdobeRGB) and save them both (as JPGs for instance).

                                                                                  Now open both in a non ICC aware aplication (Internet Explorer will do just fine).Can you spot the diference?

                                                                                   

                                                                                  I do not know why you would want to save a re-assigned image or view it some where else, it is only a means to an end, CMYK.

                                                                                  • 39. Re: Color Management forum
                                                                                    Miguel Curto Community Member

                                                                                    The diference between those two images is only the tag or the labbel so to speak.ICC aware apps as Photoshop,Mac Preview or Safari (this is new to me) are "smart" enough to try to translate those RGB values to your monitor values.The values between those images are exactly the same...youre only changing its name to trick those apps to render the values in a diferent manner.

                                                                                     

                                                                                    It may work,and toure right..its not random but it would be considered as "exploit" and in my view two wrongs dont make one right.

                                                                                     

                                                                                    Having said that,theres a lot of things that make no sense that in the end might suit some needs.

                                                                                     

                                                                                    Ramon might slam me for this but Ill give you an example:

                                                                                     

                                                                                    Theoretically if you start with a 8bit/channel image theres no point in converting to 16bits for editing.But it so happens that Photoshop "mechanics" work better in 16bits so in the end (for extreme corrections) there is a real and mesurable gain (Wich I can post here to proove)

                                                                                     

                                                                                    In that process youre throwing away some "finess" in color witch should be adress as editing image but nothing is writen in stone and as long you REALLY understand the implications of what youre doing theres no WRIGHT or WRONG.

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