1 2 3 Previous Next 114 Replies Latest reply: Sep 3, 2012 6:19 PM by Hudechrome Go to original post RSS
      • 80. Re: Weird Crop tool behaviour with 16-bit files
        Noel Carboni Community Member

        Actually I don't consider the choice of Bicubic as a workaround, since I consider it a better method for resampling in general than either of the two "newer" methods (ESPECIALLY Bicubic Sharper, which adds horrendous sharpening artifacts).

         

        I do hope Adobe gets to the bottom of this display inaccuracy issue though (which is apparently display driver-specific).  It's not nice to be deceived by the document display.

         

        Given that the AMD folks are not releasing new drivers very often any more, it'll probably be a while before we see a newer driver for ATI cards, and I want to believe that Adobe will be able to find a different way to use the GPU facilities so as to avoid these visible inaccuracies.

         

        My intuition tells me that the document quality itself is not adversely affected by the use of 16 bits/channel mode - that this is just a display issue.  But I respect your wanting to be wary of it.

         

        -Noel

        • 81. Re: Weird Crop tool behaviour with 16-bit files
          Noel Carboni Community Member

          13.0.1 Update

           

          I cannot reproduce this problem with the 13.0.1 code and ATI Catalyst 12.8.  I'm wanting to call it fixed in all facets.

           

          Anyone else care to try?

           

          -Noel

           

          Message was edited by: PECourtejoie

          • 82. Re: Weird Crop tool behaviour with 16-bit files
            erickellerman Community Member

            I'm a Mac user, so I am testing 13.0.1 under different circumstances than yours, Noel. I report no change. The suit patterns are still there.

            • 83. Re: Weird Crop tool behaviour with 16-bit files
              Noel Carboni Community Member

              Just to be clear, the patterns you saw were getting generated into the files you were saving.  Have you recreated them from what should be smooth data using only 13.0.1?

               

              -Noel

              • 84. Re: Weird Crop tool behaviour with 16-bit files
                Noel Carboni Community Member

                Never mind, motivated by your response I went back to trying it again.

                 

                I managed to reproduce it with 13.0.1.  I don't know what I missed or did wrong before.

                 

                Please scratch what I said in post 81 above.

                 

                Apparently the problem still exists.  But now I can create it using simple Bicubic resampling. 

                 

                TransparencyInaccuracy.png

                 

                -Noel

                • 85. Re: Weird Crop tool behaviour with 16-bit files
                  Noel Carboni Community Member

                  I did happen upon one other tidbit of information...

                   

                  The "pattern" of visible transparency on the screen is ONLY visible to me if the layer with the minor transparency glitches is above nothing - i.e.,

                   

                  It's the process that's trying to make the checkerboard show through that's in error.

                   

                  It is NOT visible when rendering the layer with the slight transparency glitches above a solid layer (e.g., a solid fill layer).  It only becomes visible in this case with sets of extreme curve adjustment layers added over the top, at which point the color can be seen showing through.

                   

                  -Noel

                  • 86. Re: Weird Crop tool behaviour with 16-bit files
                    Hudechrome Community Member

                    I gave it a try and I can see it without any extreme adjustments like in curves. It's a slight brown patterning on the black.

                     

                    Now this monitor has excellent black separation so maybe I can see it w/o extracting the pattern with curves.

                     

                    Also, it's a function of the actual pixel density. I tried it with a 10,000x10,000 px dimension and I could not se it at any magnification. At 600%, I suddenly get a fly screen looking pattern that doesn't resolve by going to 8 bit. My first try was 200x200px., then 10,000x10,000.

                     

                    I also tried it with Graphics Processor disabled, and no patterns showed up.200x200px.

                     

                    I don't understand from where Chris is coming. There is no transparency layer when I create the test object.

                    • 87. Re: Weird Crop tool behaviour with 16-bit files
                      erickellerman Community Member

                      I'm making a new file, 800x800, 16-bit, transparent, filling it with black and rotating with the crop tool. The GP is enabled. Bingo! Suit patterns! Disable the GP, try again, suit patterns gone.

                      • 88. Re: Weird Crop tool behaviour with 16-bit files
                        Hudechrome Community Member

                        Update:

                         

                        If I perform the test with Delete Cropped Pixels checked, I do not see the suit patterns, or any other.

                        • 89. Re: Weird Crop tool behaviour with 16-bit files
                          conroy Community Member

                          Noel Carboni wrote:

                           

                          Apparently the problem still exists.  But now I can create it using simple Bicubic resampling. 

                           

                           

                          Noel, closely check CS5.1 again to see that regular Bicubic had the problem, anyway. A specific example is resize 256 x 256 to 400 x 400.

                          • 90. Re: Weird Crop tool behaviour with 16-bit files
                            Hudechrome Community Member

                            I see nothing using resampling.

                            • 91. Re: Weird Crop tool behaviour with 16-bit files
                              conroy Community Member

                              Hudechrome wrote:

                               

                              I see nothing using resampling.

                               

                               

                               

                              Here are example screenshots:

                               

                              1. The original document is 256 x 256 pixels, 16 bpc, Adobe RGB 1998. The one black layer (there is no Background layer) cannot be distinguished from the black window background.

                               

                              Screen-shot-2012-09-01-at-22.58.54.png

                               

                               

                              2. The document is "Bicubic" resampled to 400 x 400 pixels. A network of horizontal and vertical lines where the transparency grid wrongly shows is barely visible.

                               

                              Screen-shot-2012-09-01-at-22.59.25.png

                               

                               

                              3. Photoshop displaying screenshot 2 with a region given an exposure enhancement in case anyone's monitor or vision is preventing perception of the lines in screenshot 2.

                               

                              Screen-shot-2012-09-01-at-23.04.18.png

                              • 92. Re: Weird Crop tool behaviour with 16-bit files
                                Hudechrome Community Member

                                OK, I simply used Background. Changing it to a Layer (Layer0) I can reproduce it except Exposure does not enhance the image. No change. But, if you change from 16 bit to 32 bit the lines disappear.

                                • 93. Re: Weird Crop tool behaviour with 16-bit files
                                  conroy Community Member

                                  Hudechrome wrote:

                                   

                                  OK, I simply used Background. Changing it to a Layer (Layer0) I can reproduce it ...

                                   

                                  Yes, I suspected that you were using Background and that's why I made a point of stating that there was no Background layer in my example. Background never has any transparency and so it will always block the transparency grid (gray and white checkered display by default) from being visible.

                                  ... except Exposure does not enhance the image. No change.

                                   

                                  My third screenshot showed an exposure increase being applied to the second screenshot. The exposure adjustment was not being applied in the actual document with the resampled layer.

                                   

                                   

                                  But, if you change from 16 bit to 32 bit the lines disappear.

                                   

                                  If I change mode from 16-bit to 32-bit mode, the lines become feinter but they definitely do not completely disappear on my monitor.

                                   

                                   

                                   

                                   

                                   

                                   

                                   

                                   

                                   

                                  .

                                  • 94. Re: Weird Crop tool behaviour with 16-bit files
                                    Hudechrome Community Member

                                    I suspect these are artifacts and not real. Passing the eyedropper over the image showed no change from 0,0,0. So I built a grid and set it's values to L=10,a=0,b=0. It looked quite close in values to the grid generated with the upsampling. Again, the eyedropper show no change in the values as you pass over the grid. Of course, the grid doesn't print with the image if it is left on when printing so I would suspect this also may be true of these artifacts.

                                     

                                    Inasmuch as image pixel size with which I generally work is way larger than 256 or even 400 px, and inasmuch as I see no evidence of this type of grid on a 50M image at 100%, it seems moot to me. It became of interest when I saw that the effect shows up when the Background is changed to Layer 0, and layer 0 is what happens to the background if you uncheck "Delete Cropped Pixels", of course I am interested.

                                     

                                    So, hopefully this won't actually be a problem with real world image sizes, and if it does, I'll flatten everything before final output and save it as a flattened version.

                                     

                                    Lawrence

                                    • 95. Re: Weird Crop tool behaviour with 16-bit files
                                      conroy Community Member

                                      There's an explanation for this display problem in the thread. It appears that some GPUs are incorrectly blending the transparency grid with pixels which have a transparency of a tiny fraction of one percent. These pixels really should not have any transparency but tiny transparency errors are arising in bicubic resampling. The transparency is so minuscule that it shouldn't be visibly different to full opacity. The problematic GPUs are erroneously hugely magnifying these minuscule transparencies when calculating the display for your monitor.

                                       

                                      The RGB values of pixels in the resampled layer will not reveal anything. A pixel's RGB value is independant of its transparency.

                                       

                                      Don't worry about your documents. They will be OK.

                                      • 96. Re: Weird Crop tool behaviour with 16-bit files
                                        Hudechrome Community Member

                                        Yes, I saw the explanation, and I wanted to check it out for myself, especially as to whether they make a real world difference especially in the darker values, which tend to more noise problems.

                                         

                                        I never take anyone's advice about what may happen to my docs. I'll make every effort to check it out myself. One learns much in doing so!

                                         

                                        Thanks for the feedback.

                                        • 97. Re: Weird Crop tool behaviour with 16-bit files
                                          Noel Carboni Community Member

                                          Summarizing, there seem to be two problems:

                                           

                                          1.  Some resampling operations are leaving the transparency for a given layer at a value of something less than fully opaque.  A few levels out of 32769.

                                           

                                          2.  Some video cards / display drivers are making that (barely) visible.  A few levels out of 256.

                                           

                                          It probably all boils down to roundoff error at two different stages, one with the 16 bit math and one with the 8 bit math used to combine things for display.

                                           

                                          I should have thought that Photoshop would have best-in-show algorithms internally that don't do this, and in fact it used to be true.  What's amazing to me is that Adobe didn't see fit to fix either of these issues in 13.0.1.

                                           

                                          -Noel

                                          • 98. Re: Weird Crop tool behaviour with 16-bit files
                                            Hudechrome Community Member

                                            I don't think Adobe can be held responsible for video drivers making errors

                                             

                                            More to the point, these errors contaminate the 16 bit presentations, not 8 nor 32. So it isn't simply changing afterwards,  starting with either 8 or 32 bit excludes the contamination. Further, this action is unidirectional, that is reducing the size does not produce the artifact. But increasing it back to the original does produce it. Also, if the multiplier is a whole number, (2x, 3x, etc) the effect isn't present.

                                             

                                            As to large start values in the pixel number. it appears not to be present. But increasing the magnification past 65% does show it up. Example: Start  2000x2000 px. Increase size to 3521 px. Image looks clean. Magnify to 66+% and there is the pattern.

                                             

                                            So it is insidious! looking at sharpening artifacts when checking at 100% after a  size increase other than a whole number will show up, and possibly confuse the judgement of, artifacts in shadows.

                                             

                                            Proceed to go nuts trying to correct it!

                                             

                                             

                                            BTW, I still cannot use Exposure or Curves to amplify these artifacts. there is no change; the background remains dark unless I use the gamma slider, at which time the background changes to gray with no artifacts showing. I must be missing a step or two.

                                            • 99. Re: Weird Crop tool behaviour with 16-bit files
                                              erickellerman Community Member

                                              As the OP of this thread, I'd like to know if the gentleman's suit patternings show up in prints.

                                               

                                              Has anyone tried?

                                              • 100. Re: Weird Crop tool behaviour with 16-bit files
                                                Hudechrome Community Member

                                                It's a good question and since printer drivers run at 8 bit, probably not. There is a Canon printer that will run at 16 bit. That's the one to try.

                                                 

                                                But these are phantom images as a result of video card interactions. The video card is not in the path to the printer (AFAIK!)

                                                • 101. Re: Weird Crop tool behaviour with 16-bit files
                                                  conroy Community Member

                                                  Hudechrome wrote:

                                                   

                                                  I don't think Adobe can be held responsible for video drivers making errors

                                                   

                                                   

                                                   

                                                  I agree that Adobe is not responsible for OpenGL errors in a GPU's software.

                                                   

                                                  However, tiny but nevertheless real errors are being generated into the transparency of pixels in the document by Adobe's bicubic resampling code in 16-bit mode. Without these errors in the first place, the transparency grid blending errors in the GPU software would not be in effect. The most important bug(s) to fix are those in the Adobe bicubic resampling code.

                                                   

                                                   

                                                  More to the point, these errors contaminate the 16 bit presentations, not 8 nor 32.

                                                   

                                                  Not entirely true. As I told you yesterday, the tiny Adobe-generated transparency errors remain in the pixels' transparency when you switch from16-bit to 32-bit mode and the display artefacts are still faintly present in 32-bit mode.

                                                   

                                                  Switching the mode from 16-bit to 8-bit does remove the transparency errors because the errors are in the lowest bit(s) of the 16 bits and the lowest 8 bits are discarded when converting from 16-bit to 8-bit. When these Adobe-generated errors are eliminated, the GPU software produces a correct display. The GPU problem is only apparent when pixel transparency is a very small amount greater than 0; a smaller number than can be represented by 8 bits. You can check that by converting a "corrupted" 16-bit document to 8-bit then to 16-bit again. The display will now be clean because the pixels whose transparency was a minuscule amount greater than 0 now have a transparency of exactly 0.

                                                   

                                                   

                                                  Further, this action is unidirectional, that is reducing the size does not produce the artifact.

                                                   

                                                   

                                                   

                                                  That's incorrect. The bicubic resampling errors happen when upscaling and when downscaling.

                                                   

                                                   

                                                  As to large start values in the pixel number. it appears not to be present. But increasing the magnification past 65% does show it up. Example: Start  2000x2000 px. Increase size to 3521 px. Image looks clean

                                                   

                                                  No, I disagree. The problem is visible with your specific example.

                                                   

                                                   

                                                   

                                                   

                                                  BTW, I still cannot use Exposure or Curves to amplify these artifacts. there is no change; the background remains dark unless I use the gamma slider, at which time the background changes to gray with no artifacts showing. I must be missing a step or two.

                                                   

                                                   

                                                  When you said that yesterday also, I replied that I was enhancing the artefacts by increasing the exposure of a screenshot of Photoshop that I had captured when the artefacts were being displayed, and not by increasing the exposure of the resampled layer in the document. To what are you applying an exposure adjustment that doesn't enhance the artefacts?

                                                  • 102. Re: Weird Crop tool behaviour with 16-bit files
                                                    Chris Cox Adobe Employee

                                                    >> The most important bug(s) to fix are those in the Adobe bicubic resampling code.

                                                     

                                                    You're talking about 1 bit errors in the least significant bit of a 16 bit calculation, which are only visible when extreme adjustments are applied or a display driver bug is involved.  That's not a major problem.  It will be addressed, but there are much more pressing matters ahead of it in the queue.

                                                     

                                                    The big problem here is the GPU issues making those LSB errors visible - that needs to be fixed soon.  I still can't say for sure whether this is an Adobe bug (failing to account for certain GPUs), or a driver bug on certain GPUs.  But we will continue to investigate.

                                                    • 103. Re: Weird Crop tool behaviour with 16-bit files
                                                      conroy Community Member

                                                      Chris Cox wrote:

                                                       

                                                      >> The most important bug(s) to fix are those in the Adobe bicubic resampling code.

                                                       

                                                      You're talking about 1 bit errors in the least significant bit of a 16 bit calculation, which are only visible when extreme adjustments are applied or a display driver bug is involved.

                                                       

                                                      Yes, I certainly am talking about the 1 bit errors. If these 1 bit errors created by Adobe's bicubic resampling weren't present then the suspected display driver bug would never have a visible result whether that display driver bug exists or not.

                                                       

                                                      It seems that the display corruption doesn't arise unless only the least significant bit of 16 is set in a pixel's transparency.

                                                       

                                                      The Adobe error is the initial error in a chain of errors. Eliminate that initial error and there will be no display problem regardless of the display driver.

                                                       

                                                      ---

                                                       

                                                      This is an edited form of a now deleted post.

                                                      • 104. Re: Weird Crop tool behaviour with 16-bit files
                                                        Hudechrome Community Member

                                                        Are there any resampling algorithms other than bicubic suitable for resizing that does not show these artifacts? And FAPP, the main problem is that confusion as to true artifacts visible in printing and those visible on the screen interfering with corrective measures. It's no small consideration.

                                                         

                                                        My bad missing the screen shot as the source for Exposure change.Unfortunately, that would be no aid to clarifying the confusion factor in real time.

                                                         

                                                        We disagree on what we see. My assertion concerning the 2k x 2k resample sighting stands for this equipment. It literally snaps into view as the magnification changed from around 65% to beyond 66%.

                                                         

                                                        I'll not bother much with those differences, leaving all this up to Chris and his people.

                                                         

                                                        Bottom line: Dupe the 16 bit file flatten and reduce to 8 bits when doing noise and artifact checking on a given image. I'm going back to certain files and look in the next few days.

                                                        • 105. Re: Weird Crop tool behaviour with 16-bit files
                                                          conroy Community Member

                                                          Hudechrome wrote:

                                                           

                                                          Are there any resampling algorithms other than bicubic suitable for resizing that does not show these artifacts

                                                           

                                                           

                                                          Bilinear and Nearest Neighbor don't have the problem, but you probably won't like Bilinear's inferior results and you almost certainly won't like Nearest Neighbor. Try them, though. You are the one who has to decide what looks acceptable.

                                                           

                                                           

                                                           

                                                          And FAPP, the main problem is that confusion as to true artifacts visible in printing and those visible on the screen interfering with corrective measures. It's no small consideration.

                                                           

                                                           

                                                          Yes, certainly.

                                                           

                                                           

                                                           

                                                          We disagree on what we see. My assertion concerning the 2k x 2k resample sighting stands for this equipment. It literally snaps into view as the magnification changed from around 65% to beyond 66%.

                                                           

                                                           

                                                          If "Cache Levels" is greater than 1 (which it is by default) in Preferences > Performance, the display calculation of 16-bit documents is streamlined to 8 bits when zoom is less than about 65%. Therefore the artefacts will not appear below that zoom level and will suddenly appear when you go over that zoom threshold into 16-bit display calculation.

                                                          • 106. Re: Weird Crop tool behaviour with 16-bit files
                                                            Hudechrome Community Member

                                                            I was thinking of other than PS for resampling, like Fractal Images. But thnks for the heads up about the others in PS.

                                                             

                                                            I just tried the 2k x 2k resampled to 3521 setting Cache to 1 and got the same result. Specifically, no artifacts at 63.26%, artifacts visible at 64.84% and above.

                                                             

                                                            Conventional wisdom anyway is check 100%.  So I checked again at 100% with a 5k x5k file resampled up to 7531. At 100%, it is visible. Cache size not a factor.

                                                            • 107. Re: Weird Crop tool behaviour with 16-bit files
                                                              Noel Carboni Community Member

                                                              Trouble is, it's not just image size resampling but anything that uses resampling that's affected.  Hence rotating while cropping is implicated in the thread above.

                                                               

                                                              As for whether it's purely a display driver fault, I'm not completely willing to believe Adobe has no fault in this.  Has anyone got a GPU on which the problem doesn't happen?

                                                               

                                                              -Noel

                                                              • 108. Re: Weird Crop tool behaviour with 16-bit files
                                                                conroy Community Member

                                                                .

                                                                Repost with proper screenshots (there was a conversion problem)

                                                                 

                                                                 

                                                                Hudechrome wrote:

                                                                 

                                                                I just tried the 2k x 2k resampled to 3521 setting Cache to 1 and got the same result. Specifically, no artifacts at 63.26%, artifacts visible at 64.84% and above.

                                                                 

                                                                Conventional wisdom anyway is check 100%.  So I checked again at 100% with a 5k x5k file resampled up to 7531. At 100%, it is visible. Cache size not a factor.

                                                                 

                                                                 

                                                                Cache size is a factor when the zoom is below about 64% here, which entirely accords with how the 16-bit mode display is streamlined to 8-bit calculations below that zoom threshold when Cache Levels is greater than 1. Artefacts popped into the display of Cache Levels 4 only when zoom was 63.77% or greater, but they were always visible with Cache Levels 1, as expected.

                                                                 

                                                                Here are screenshots to illustrate.

                                                                 

                                                                Screen-shot-2012-09-03-at-00.23.27.png

                                                                 

                                                                Screen-shot-2012-09-03-at-00.22.00.png

                                                                 

                                                                Screen-shot-2012-09-03-at-00.14.55.png

                                                                 

                                                                Screen-shot-2012-09-03-at-00.15.03.png

                                                                • 109. Re: Weird Crop tool behaviour with 16-bit files
                                                                  Hudechrome Community Member

                                                                  "...but they were always visible with Cache Levels 1, as expected."

                                                                   

                                                                  What part of "Not here" don't you understand? I am getting different results due to what I don't have a clue, nor do I really care. !00% has no competition. In fact, all tests run using a pixel count from 1024 x1024 down will be at 100% or greater if you use "fit screen" or Ctrl +Alt 0. So I leave my cache at four, run at 100%, the measurement problem resolves, so far as visuals are concerned.

                                                                   

                                                                  Years ago, I had serious problems with a design I implemented using image mirroring. The file size got great but I didn't watch at 100%. I thought I had a design with burgundy as the central color but either flattened or 100% I had mustard.

                                                                   

                                                                  You might say that didn't cut the mustard at all!

                                                                  • 110. Re: Weird Crop tool behaviour with 16-bit files
                                                                    Hudechrome Community Member

                                                                    I wondered about that as well, Noel. You and I are running Ati cards. I don't know where you have landed with their drivers but I amusing the latest, 12.8

                                                                    • 111. Re: Weird Crop tool behaviour with 16-bit files
                                                                      conroy Community Member

                                                                      Hudechrome wrote:

                                                                       

                                                                       

                                                                      What part of "Not here" don't you understand?

                                                                       

                                                                      Look who's talking!

                                                                       

                                                                      Read my first sentence. I deliberately preceded my results with the word "here" just as you did.

                                                                      • 112. Re: Weird Crop tool behaviour with 16-bit files
                                                                        Hudechrome Community Member

                                                                        Well, you were repeating yourself. I can only assume by doing that, you didn't understand my response, didn't care, whatever.

                                                                         

                                                                        Also I did NOT use that "smiley" in the sentence you quoted.

                                                                         

                                                                        Give it a rest. I'm done.

                                                                        • 113. Re: Weird Crop tool behaviour with 16-bit files
                                                                          conroy Community Member

                                                                          Hudechrome wrote:

                                                                           

                                                                          Well, you were repeating yourself. I can only assume by doing that, you didn't understand my response, didn't care, whatever.


                                                                           

                                                                          Your assumption was wrong.

                                                                           

                                                                          Repeating myself? You posted information that your findings were different from mine. I could have been in error so I posted some evidence of what I was getting on my system. Please don't be upset by me posting something contradictory to your post. It wasn't a personal attack.

                                                                           

                                                                           

                                                                           

                                                                          Also I did NOT use that "smiley" in the sentence you quoted.

                                                                           

                                                                           

                                                                          Sorry about the smiley accident. I honestly must have missed the last character in the quote of your message when removing the second half of the quote.

                                                                          • 114. Re: Weird Crop tool behaviour with 16-bit files
                                                                            Hudechrome Community Member

                                                                            I did a practical test today to assess this problem in working with photos, and I have to say it is a revelation. I opened a file, used "Convert to Smart Object" (quicker than crop or rotate) it to a specific image size like 36" then examined the deep grays. With a large black surface the pattern was obvious, but I seldom go that black. Where it became an issue is in densities represented in the bit dept between 2 and 10, especially around 8. I can see and print these values, (6 and above) and what I saw was a sort of fuzziness I've seen before when magnifying that went away when I flattened the image. I never went any further because the flattened image cleaned it up and I usually do the final inspection less than 100%. Of course, the print is always fine.

                                                                             

                                                                            So, no damage done to the image itself but a certain uncertainty lingered around the degree of magnification. Was I going to far within the quality expectations I place on my large prints? No, but until now, I did not know why.

                                                                             

                                                                            So, it's a good find, and I thank everyone for their contributions.

                                                                             

                                                                            -Lawrence

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