11 Replies Latest reply on Jul 11, 2009 10:56 AM by xbytor2

    Color shifting when Raw image is converted to .jpg

    Bruce Pollock

      I'm experiencing a strange situation that I hope someone can help me with.  My objective is to produce some .jpgs from Raw files for posting to the web or for making C prints at my local photofinisher.

       

      I make basic corrections to an image in Camera Raw and, when I'm satisfied with color balance, etc. I open it in PS.  Next step is to reduce the file size, convert to 8 bits and save as a .jpg.  At that point, the image still looks good in PS and in ACR.

       

      However, the moment I post the .jpg to the web or attach it to an email to send to someone, the resulting file shifts to a greenish/cyan cast, it appears darker and more contrasty.  I have not yet tried to print one of these images (C print) to see what the results are.  The following link may give some idea of the problem, although, of course, you can't see the color quality of the original for comparison.

       

      http://www.flickr.com/photos/30463986@N07/3685504625/

       

      Can anyone explain why this color shift happens and perhaps suggest a solution?  I want to post images to a web site, but the results look terrible.

       

      Thanks for any assistance.

        • 1. Re: Color shifting when Raw image is converted to .jpg
          Bruce Pollock Level 1

          A follow-up in case these additional facts are helpful.

           

          I'm using a Vista OS with CS3.  I convert my .CR2 images to .dng using the Adobe DNG converter before opening in ACR.

           

          Thanks again.

          • 2. Re: Color shifting when Raw image is converted to .jpg
            Bruce Pollock Level 1

            OK - never mind.  I solved my own problem.

             

            It was obviously a color space issue, but I'm a newby and didn't know what I was doing.  I've been reading the Schewe/Fraser book on ACR (great book by the way) and was sort of following Jeff's lead by setting my preferences to ProPhoto RGB.  When I open in PS and convert to .jpg, the resulting color shift is huge.

             

            I've gone back to simply using the sRGB color space in ACR and things look fine.

             

            If anyone is still interested in my dilemma and ramblings, I'd now be interested in learning when and why to use the ProPhoto color space.  I know that it is a very wide gamut, but if I'm going to be converting for print output, is there any real advantage to using it?

            • 3. Re: Color shifting when Raw image is converted to .jpg
              Ramón G Castañeda Level 4

              Bruce Pollock wrote:

               

              …I'd now be interested in learning when and why to use the ProPhoto color space. 

               

               

              Not before you really and thoroughly know what you're doing.  No offense meant at all, but for now stick to sRGB for the web and Adobe RGB for print.

               

              Learn about color management.  It's a loooooooooong journey, but you can start here:

               

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

              1 person found this helpful
              • 4. Re: Color shifting when Raw image is converted to .jpg
                Jeff Schewe Level 5

                Bruce Pollock wrote:

                 

                I've gone back to simply using the sRGB color space in ACR and things look fine.

                 

                That's a fine short term solution for your dilemma but while it got you back to reasonable color for the web, it's not optimal for long term image archiving nor fine art printing to any of a variety of ink jet printers whose gamut of color has color well beyond that of sRGB.

                 

                Keep reading...and learning and you'll prolly be back to Pro Photo RGB. BTW, you can easily solve your color space issue by doing a Convert To Profile command and convert your Pro Photo RGB images to sRGB for the web and email while saving the full Pro Photo RGB gamut 16 bit/channel image for later use.

                1 person found this helpful
                • 5. Re: Color shifting when Raw image is converted to .jpg
                  Bruce Pollock Level 1

                  Thanks to Ramon for the link and Jeff for the guidance.

                   

                  Although I'm a digital newby, I've got 35 years of analogue experience behind me - that's the main reason why Raw appeals to me.  There's an intuitive connection to the way I'm used to dealing with printing and colour correcting.

                   

                  However, this colorspace thing is a whole new issue.  I've followed Jeff''s advice and have gone back to preferring the ProPhoto space in ACR and when I intend to export to a .jpg, I've figured out how to do the Convert to Profile and move the image into sRGB.  As I worked through this exercise, I noticed that, somehow, the target colorspace had been set to CMYK.  That probably explains why the resulting .jpgs were so ugly.

                   

                  One final question.  If I want to save as a .tif, are there any issues with continuing to use the ProPhoto colorspace?  In other words, not converting to sRGB?  If I want to make C prints or print to an inkjet will there be any problems at my lab?

                   

                  Thanks again for your assistance - I learned a lot today.

                  • 6. Re: Color shifting when Raw image is converted to .jpg
                    Ramón G Castañeda Level 4

                    Bruce,

                     

                    No problem saving a ProPhoto RGB image as a TIFF.

                     

                    Whether your lab can deal with that is a different question.  Only top pro labs will know how to handle that.  Your run of the mill commercial lab will expect sRGB JPEGs from you.

                     

                    The reason I cautioned you about ProPhoto RGB is that your ProPhoto RGB images will contain out-of-gamut colors, and you have to deal with that.  Additionally, one needs to be fully aware of the difference between the rendering intents when converting to sRGB.  Relative Colorimetric will clip out of gamut colors while Perceptual will compress the entire range of colors to make them fit.

                     

                    Personally, I only use ProPhoto RGB and I prefer PSDs over TIFFs.  I've been shooting for well over half a century now.

                    • 7. Re: Color shifting when Raw image is converted to .jpg
                      Jeff Schewe Level 5

                      Bruce Pollock wrote:

                       

                      If I want to make C prints or print to an inkjet will there be any problems at my lab?

                       

                      Oh, you'll have lot's of problems...most photo labs have bought into the sRGB Kool-Aid amd demand that photographers supply images in sRGB because they "claim" that their printers are sRGB devices-which is a load of crap. They are sRGB devices because the Fuji and Noritsu printers all have sRGB print modes and the labs like that cause their minimum wage button pushers don't have to deal with color management issues.

                       

                      Which is ironic because here in the USA a company called Costco has adopted color management and has had custom profiles made for most of their lab locations around the country. So, if you live in an area with a Cosco you can use a color managed workflow using free profiles you can download from their web site.

                       

                      But in terms of photo labs, you really have to bit the bullet and just deliver sRGB images which you can convert in 16 bit and take advantage soft proofing then to a convert to profile. Note, is they also demand JPEGs (typical) you'll also need to drop down to 8 bits/channel as well. Ain't no 16 bit JPEGs ya know?

                       

                      :~)

                      • 8. Re: Color shifting when Raw image is converted to .jpg
                        Bill_Janes Level 2

                        Ramón G Castañeda wrote:

                         

                        The reason I cautioned you about ProPhoto RGB is that your ProPhoto RGB images will contain out-of-gamut colors, and you have to deal with that.  Additionally, one needs to be fully aware of the difference between the rendering intents when converting to sRGB.  Relative Colorimetric will clip out of gamut colors while Perceptual will compress the entire range of colors to make them fit.

                         

                         

                        Unfortunately, with matrix profiles such as sRGB and ProPhotoRGB, there is no perceptual rendering but only Relative Colorimetric; thus, when converting from ProPhotoRGB to sRGB, out of gamut colors will be clipped. When dealing with labs that do offer a profile for their printers, it is best to leave the image in ProPhotoRGB and then convert to the printer profile. Then one can use Perceptual or Relative Colorimetric rendering, which ever gives the best result as shown by softproofing.

                         

                        As Jeff Schewe mentioned, Costco is one reasonably priced lab that does offer profiles. My local Costco in Glenview, IL provides profiles through DryCreek.com that you can download for free. However, for their Noritsu printer using Fuji Crystal Archive paper, the gamut of the printer is hardly larger than sRGB, so you can't really make good use of those saturated colors you can get with ProPhotoRGB; however, you do gain some control over how they are printed. Inkjet printers have a much wider gamut, and even a relatively old printer such as the Epson 2200 with premium glossy paper far exceeds the gamut of sRGB, so if you plan to repurpose the images, ProPhotoRGB lets you keep your options open.

                        • 9. Re: Color shifting when Raw image is converted to .jpg
                          xbytor2 Level 4
                          Unfortunately, with matrix profiles such as sRGB and ProPhotoRGB, there is no perceptual rendering but only Relative Colorimetric; thus, when converting from ProPhotoRGB to sRGB, out of gamut colors will be clipped.

                           

                          OK. I'm confused. What does this mean in terms of 'Convert to Profile' in Photoshop? I can select either perceptual or relative colorimetric as rendering intents when converting from ProPhotoRGB to sRGB. Does PS ignore perceptual and always do relative colorimetric?

                          • 10. Re: Color shifting when Raw image is converted to .jpg
                            Bill_Janes Level 2

                            xbytor2 wrote:

                             

                            Unfortunately, with matrix profiles such as sRGB and ProPhotoRGB, there is no perceptual rendering but only Relative Colorimetric; thus, when converting from ProPhotoRGB to sRGB, out of gamut colors will be clipped.

                             

                            OK. I'm confused. What does this mean in terms of 'Convert to Profile' in Photoshop? I can select either perceptual or relative colorimetric as rendering intents when converting from ProPhotoRGB to sRGB. Does PS ignore perceptual and always do relative colorimetric?

                             

                            Yes, that is true. IMHO, the perceptual rendering should blanked out on the dialog. As it is, it is merely ignored.

                            • 11. Re: Color shifting when Raw image is converted to .jpg
                              xbytor2 Level 4
                              Yes, that is true. IMHO, the perceptual rendering should blanked out on the dialog. As it is, it is merely ignored.

                               

                              Thanks. Some quick testing confirmed this. This was my 'one new thing' to learn today. I can finally leave for the pub...