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This is what I typed in my reply to your post in the ACR forum:
Ramón G Castañeda, "Convert RAW from ACR to profile?" #5, 4 Dec 2008 6:56 pm
To go to a different color space than one of the profiles in ACR, go through ProPhoto RGB. It is essentially the same as ACR's internal working space and you will lose absolutely nothing.
That's why you need nothing else.
>pRGB, sRGb,aRGB and rRGB?
what do you mean by rRGB?
The four output color spaces offered by ACR are ProPhoto RGB, Adobe RGB (1998), ColorMatch RGB and sRGB IEC61966-2.1.
Where do you get rRGB from?
>>Where do you get rRGB from?<< yes. you right. i meam to colormatch...
here may broblem in 4 color space: let's say i open my file picture in ACR. and then i want this picture in pRGB color space. ok. i choose pRGB and then open in photoshop. but here the broblem: i canot do ASSIGN to pRGB? to do make assign may picture to pRGB i must choose different color space in ACR and only then make in photoshop assign to pRGB. and this it's A BROBLEM - what color space choose in ACR to do a good sssign to pRGB? from sRGB or cRGB or aRGB?
What do you mean by pRGB?
Sorry, but your last post makes absolutely no sense. No sense whatsoever.
You NEVER assign a color in Photoshop to an already tagged image. Ever! Under no circumstances!
The only time you use "assign" is when some idiot hands you an untagged file and you have to come up with an educated guess as to what color space the file was created and saved in.
If you select ProPhoto RGB in ACR, your file will already be in ProPhoto RGB. You don't have to worry about "assigning" anything. You may however use CONVERT to go to any other profile of your choice.
Do not confuse convert and assign. Convert maintains the colors and changes the numbers accordingly. Assign maintains the numbers and changes the colors to something else.
>to do make assign may picture to pRGB i must choose different color space in ACR and only then make in photoshop assign to pRGB.
That is utter nonsense, Kokii. :/
Incidentally, is Arabic your native tongue? Knowing the answer may help me come to terms with your prose.
>>If you select ProPhoto RGB in ACR, your file will already be in ProPhoto RGB. You don't have to worry about "assigning" anything. You may however use CONVERT to go to any other profile of your choice.
but this it's a broblem - ProPhoto RGB it's a limit to Large space? this it's a basis to start?
why? i want more large color space from profhoto RGB... did you not want? and then you have more choose to convert.. or more choose to color correction? no?
ProPhoto RGB is wider than anything else you can come up with, Kokii, at least in term of usable gamut.
Obviously we are not communicating well.
ok. but do you think in a future only ProPhot RGB be? certainly no.
so why not now?
pRGB=ProPhotoRGB is an extremely large space. Use this
in ACR with 16 bits per channel (bpc) as an intermediate
color space (a transfer format).
In Photoshop you can convert the file into any other space,
for instance sRGB, aRGB=AdobeRGB, or my oRGB=OptiRGB.
The first steps of image processing, mainly levels corrections,
can or should be done with 16 bpc, but then you can continue
with saving by 8 bpc (my humble opinion, but shared by experts).
If you want to continue editing in PhS by pRGB, then you
should use 16 bpc.
These abbreviations are based on my suggestions:
sRGB = Standard RGB
aRGB = Adobe RGB (1998)
pRGB = ProPhoto RGB
oRGB = OptiRGB
Best regards --Gernot Hoffmann
I like do it color correction in pRGB. that way i interest to more large space - more choose to color correction in image.
It would help to know exactly what you are doing, kokki, what industry you are in, where you get your files from and what you print them on.
I still have no idea what you really mean.
we now when we do it color correction on pRGB we have more large histogram. right? and then we do it convert to some profile we want (to be said aRGB). and then we do it print in epson 8 ink or Canon 12 ink.
to imagine if we have more large pRGB and then do it convert to aRGB. if you have more large space you have more large histograma to color correction.
> Incidentally, is Arabic your native tongue? Knowing the answer may help me come to terms with your prose.
It's dyslexia--see Kokii's explanation below:
kokii, "profill from camera or ps?" #13, 26 May 2008 12:55 pm
Sorry, Kokii, but I still can't make any sense of what you say.
If only ProPhoto RGB and Adobe RGB are involved, then what is your problem? Both are offered by ACR.
There's more than dyslexia involved in this miscommunication.
more large space more large histograme to color correction in yoer file image. pRGB it's not enough basis in ACR for today! what yours broblem to more large basis in ACR?
I'll try just one more time:
ProPhoto RGB is as large as it will ever get in ACR, as large as anybody will ever need. It is also essentially the internal working space of ACR.
Any other color space you can think of is included inside the gamut of ProPhoto RGB.
What you just wrote
>pRGB it's not enough basis in ACR for today!
is the biggest nonsense you or anybody else has ever written on these forums.
Why can't you understand that ProPhoto is "the mother of all color spaces" , to use a familiar expression? There is NOTHING larger available in this context.
I don't have any "broblem" or "broblems" (;)) with any color space in ACR or anywhere else, I just have a big problem understanding where you're coming from.
I ask you again, this time for the last time: what "other" color space are you thinking of that you would like to work in"?
>The first steps of image processing, mainly levels corrections
"Levels" corrections these days are considered to be on the same plane as using a chain saw for brain surgery. Aside from the fact that the black point and the white point can be easily set in ACR, Curves adjustment layers are the way to go in Photoshop in most modern workflows.
I have the feeling we're opening a can of worms here with references to obsolete workflows espoused by, err other folks. ;) I have actually witnessed people coming to blows over this at round table conferences. :/
On the question of the salutation in my previous post, it was very awkward for me to write only the first name of someone known to me to be a Professor. Sorry, but I just can't help it. Meine akademische Bildung an deutschen Universitäten in den sechziger Jahren macht mich unausweichlich zum altmodischen Muffel. :/
This might help:
You can download the PDF to read an essay by Jeff Schewe titled "A Color Managed Workflow" and view the above image in context.
As you can see, neither sRGB nor even Adobe RGB contain the entire gamut printable on an Epson 2200 on matte paper. the much larger ProPhoto RGB working space can.
today we have aRGB print and panel pRGB in computer. pRGB in this day it's not enough limit.
do you really think pRGB it's a limit to future!?
Ramon is correct....ProPhoto is MORE than enough. It is an extremely WIDE color space with a HUGE gamut. If you can see beyond that, you are either able to see into the infrared and UV spectrum, or perhaps you are the son of Superman! I'd stop splitting hairs and get on with editing and printing images, unless you are developing software or designing editing spaces.
Most output devices cannot even display or print much of the ProPhoto gamut. In fact, many colors defined within ProPhoto extend beyond human vision. Looking for a color space larger than ProPhoto is unreasonable, in my opinion.
Yes i now the space ProPhoto extend beyond human vision. and i agree with Ramon with this. but i try say something additio and it's hard to me because i am dyslexic and inglish it's not may language. so please a litle patien.
so i try again: when we open image in ACR and then convert to pRGB and then open in photoshop, we have more large histograma to color corecation on image. we have more "data". but this image it's not realy a pRGB with all possibility. because even when we convert in ACR to pRGB it's not like assign we have full pRGB in limit data in image. so if we have more large space from pRGB and them we convert to this large space we have more large histograma to color corecation.
example: take image in color space cmyk and open in photoshop and then convert to pRGB - it's not say this image be came full pRGB? "beyond human vision". no. it's still "cmyk" but more space to color corecation. so. if we have more large then pRGB then we have more space to "play" "data" on color corecation. so if i open may image in ACR and then convert to pRGB it's not say i have full pRGB "beyond human vision". no. it's say only i have more choose to histograme and color corecation.
A RAW digital image in its pure form is a matrix of B&W data captured through red, green and blue filters, and really does NOT have any true color until we render it using a RAW converter. When you set the color temperature, tint, contrast, brightness, etc, you are instructing the RAW converter to convert and 'dematrix' the file, and while doing so, make sure that the file is rendered in color as an sRGB, Adobe RGB, ColorMatch RGB or Prophoto RGB file.
So, if you choose ProPhoto RGB as your space in ACR, the conversions will be made to fit your file's data into the ProPhoto editing space, using the endpoints, color temp, etc, and other adjustments you made in ACR. When it arrives in Photoshop, it IS a Prophoto RGB file...period. At that point, you can choose to convert to another profile if you wish, or leave it in ProPhoto. Assigning another profile at that point will change the colors, which is usually not the desired result.
Most images don't need ProPhoto RGB and come nowhere near needing its extended gamut. Converting a typical CMYK to ProPhoto RGB is usually silly, since the CMYK file has a VERY limited gamut. Usually Adobe RGB or sRGB is more than adequate. Even if these spaces clip a few colors, they are rarely noticeable. Most monitors cannot display the full Adobe RGB space, and most output devices are smaller than Adobe RGB, though some colors lie marginally outside ARGB.
I'm really not sure what you are trying to accomplish. Personally, I am not a proponent of ProPhoto, and never use it for editing. Others do, and that is fine, as long as they are knowledgeable and work in 16 bit. The only time I do use it is as an intermediate space when converting a file from ACR, and only on a handful of images. As soon as that file arrives in Photoshop, I immediately convert to PhotoGamut RGB if I need extended gamut for printing. To each his own. But normally, I find that sRGB is adequate for about 75% the files I print, and with very few exceptions, the remainder are adequately covered by using Adobe RGB. So, I generally use those spaces when converting in ACR. Those files arrive in PS as srgb or adobe rgb files.
I don't know if that explains things or not, but hopefully it is a bit clearer.
I certainly hope this doesn't degenerate into a discussion of the pro's and con's of ProPhoto vs other editing spaces. We've beaten that to death.
When you output the image from ACR in ProPhoto RGB you are getting all possible colors, all that are possible now, and all that will ever, ever be possible unless you change the laws of physics and of biology.
What you say makes absolutely no sense whatsoever.
If anything, those who criticize ProPhoto RGB say it is TOO LARGE a space already.
You can output your image from ACR into ProPhoto RGB and then convert it in Photoshop to whatever color profile you want, whether an existing one or one you invent yourself in the future, or any color space anyone pulls out of his rear end in the future, without losing any colors.
Lou is correct:
> Converting a typical CMYK to ProPhoto RGB is usually silly
I would even substitute the adverb usually with something like monumentally.
>when we open image in ACR and then convert to pRGB and then open in photoshop, we have more large histograma to color corecation on image. we have more "data". but this image it's not realy a pRGB with all possibility.
That is dead wrong. You are absolutely wrong!
What you have in the scenario you describe is indeed an image created in the ProPhoto color space (you are not "converting it") and correctly tagged as ProPhoto RGB.
Sorry, but this is neither a dyslexia nor a language-barrier issue. The problem is that you have no understanding of color theory or color management at all.
ACR ( and Lightroom 2.0 which will export to any RGB space you have an installed profile) uses ProPhoto RGB primaries for all its color processing (in linear encoded gamma). So there's no reason to have a "larger" space.
Kokii, you'd have to convince Adobe to use a different processing color space, good luck with that one!
>>Kokii, you'd have to convince Adobe to use a different processing color space, good luck with that one<<
In year 2019 (Photoshop CS12 and Epson or Canon pRGB ink space 32bit and good 'teco' Paper proofing and well every pc have panl pRGB) perhaps Adobe...
perhaps adobe say: "beyond human vision?! how care what the man saw in a past!"
did this young man saw...
"YES WE CAN"...
>You can download the PDF to read an essay by Jeff Schewe titled "A Color Managed Workflow" and view the above image in context.
That is an excellent reference, but the illustration does not make the best case for ProPhotoRGB since it is a 2D representation of a 3D space, probably at L = 50. The Epson printers can print saturated greens at lower luminances and it is with these lower luminances that they excel. Bruce had noted this previously prior to his untimely death.
The link below shows a graphic for the Epson 2200 with Premium Luster paper. Note the out of gamut green at low luminance (out of gamut colors extend beyond the wire-frame). Luminance from 0 to 100 is on the Y-axis.
>Bruce had noted this previously prior to his untimely death.
If he had noticed it after his death, presumably you wouldn't know about it, would you? ;)
>If he had noticed it after his death, presumably you wouldn't know about it, would you?
Kokii, what profile would you want to use?
>If he had noticed it after his death, presumably you wouldn't know about it, would you?
What about "channeling"...?
In beginning it's become esiRGB.
but after this dialog "beyond human vision"... it's just to principle.
Good grief, electron spectroscopic imaging (ESI) ?
OK, let's assume that's a typo for ECI RGC.
Just compare how much smaller ECI RGB is than ProPhoto RGB:
* The gray shaded areas represent views of each of the working space gamuts, as viewed from above in Lab space, ECI RGB on the left and ProPhoto RGB on the right respectively.
* The red outline is the projection of the Lab Gamut.
* Each gamut is rendered as its L* value only, so darker shades represent darker colors, as seen especially in the blue region (lower right of each image).
© 2001 - 2008 Bruce Justin Lindbloom