8 Replies Latest reply on Apr 27, 2016 2:10 PM by trshaner

    Why don't the RGB Values Match the Percentage Values?

    JasonBatley

      If you view the attached link you will see that when I switch from Soft Proofing the RGB values do not match the percentage values of the solid red colour, according to the percent values I have 40% green in there! I wouldn't normally be concerned but LR isn't printing out my reds correctly, can anyone tell me what's going on please?

       

      http://screencast.com/t/OML7Ptz8Nai9 http://screencast.com/t/OML7Ptz8Nai9

        • 1. Re: Why don't the RGB Values Match the Percentage Values?
          trshaner Adobe Community Professional & MVP

          The LR working color space is ProPhoto RGB. You have Adobe RGB selected in the Soft Proof panel. Try changing it to ProPhoto RGB. Earlier versions of LR 6/CC 2015 showed incorrect soft proof values, which was fixed in LR 6.4/CC 2015.4. Please tell us what version of LR you are using.

          • 2. Re: Why don't the RGB Values Match the Percentage Values?
            JasonBatley Level 1

            Hi, thanks for your response. I am using LR CC, it says version 9.5 Camera Raw.

             

            OK so I sort of understand what you mean - I have gone to the Soft Proof panel and I actually selected the profile that I acutally use with my Epson printer - the colours look awful, I am getting a RGB of R255 G59 B81 for what is supposed to be solid red! If I go into Photoshop (where the file was created) I get R255 G0 B0. No matter what I do with the saturation sliders I can't get proper red in LR - can you help please?

            • 3. Re: Why don't the RGB Values Match the Percentage Values?
              trshaner Adobe Community Professional & MVP

              JasonBatley wrote:

               

              Hi, thanks for your response. I am using LR CC, it says version 9.5 Camera Raw.

               

              OK so I sort of understand what you mean - I have gone to the Soft Proof panel and I actually selected the profile that I acutally use with my Epson printer - the colours look awful

              The colors will look different if the destination color profile has a smaller gamut than the current image file's color space (and your monitor's gamut). Looking at the 2nd part of the video I do see the difference in readings and a Green spike in the histogram. This should not be happening with LR 6.5/CC 2015.5. Try unchecking 'Use Graphics Processor' in the LR Preferences> Performance tab:

              • 4. Re: Why don't the RGB Values Match the Percentage Values?
                JasonBatley Level 1

                Hi, I have just tried this and it made no difference.

                • 5. Re: Why don't the RGB Values Match the Percentage Values?
                  trshaner Adobe Community Professional & MVP

                  Let's clarify what you are actually seeing. As I understand it the original file was created in PS with a logo that is 255-0-0 Red. When opened in LR it shows readings of R 89.2, G 39.0, B 4.6 %, but in Soft Proof mode with Adobe RGB profile it shows 255-0-0 as expected.

                   

                  Can you post the file or create another file file that exhibits the issue to Dropbox or other file sharing site and provide the share link here? That's the fastest way to try and determine what's wrong. Also try clicking on the LR Master Reset button at the bottom of the Develop panel and see if you still have the issue. That way we can be sure it's not due to one of the Develop settings.

                  • 6. Re: Why don't the RGB Values Match the Percentage Values?
                    trshaner Adobe Community Professional & MVP

                    I just created a file in PS with a 255-0-0 red area and converted it to Adobe RGB color space. I'm getting very similar results as you. If I leave it in my PS working space of ProPhoto RGB it shows as 100,0,0. See below. The colors match what I see in PS, but the values are incorrect. Could be another bug caused by the fix for the Soft Proof bug....don't know!

                    Soft Proof Issue.jpg

                    Soft Proof Issue ProPhoto RGB.jpg

                    • 7. Re: Why don't the RGB Values Match the Percentage Values?
                      D Fosse Adobe Community Professional & MVP

                      Todd - does the Lightroom histogram/readout work the same way for rendered RGB files, as it does for raw files? IOW, does it remap into ProPhoto primaries and sRGB tone curve? I can't recall.

                       

                      But if so, which I suspect, this is all normal and expected.

                      • 8. Re: Why don't the RGB Values Match the Percentage Values?
                        trshaner Adobe Community Professional & MVP

                        D Fosse wrote:

                         

                        Todd - does the Lightroom histogram/readout work the same way for rendered RGB files, as it does for raw files? IOW, does it remap into ProPhoto primaries and sRGB tone curve? I can't recall.

                         

                         

                        Bingo, yes of course since that is LR's working color space! To test it I converted a 255-0-0 red image with Adobe RGB color profile in PS using ProPhoto RGB with 2.2 Gamma. The RGB values are 222, 103, 46 or in percentage 87.1, 40.4, 18.0 %, which is very close to the values observed in LR (87.6, 40.7, 16.7 %). So as you say this is perfectly normal.

                         

                        Concerning the OP's issue with the Epson printer profile I suspect it is also normal due to loss of gamut.