Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Eric Kellerman on May 31, 2012, 08:20:21 am
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I apologise if this topic has been covered elsewhere, and wonder if anyone else has encountered the following problem.
Make a new file in PS6 (RGB mode). Fill it with 100% black. Use the Crop tool and rotate to taste. Press Enter to accept the crop and zoom in to enjoy the black and grey noise patterning reminiscent of a man's suit. The Straighten tool will achieve the same result. Your suit pattern will vary according to the degree of rotation.
I thought initially that this was PS playing havoc with shadow areas of my photographs when I rotated them, but when in the interests of science I used the above procedure for the sake of comparison, I found what may be a more general problem.
Not replicable in Greyscale mode, as far as I can tell.
I'm using a Mac Pro with OS10.6.8.
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Let me guess...you are zooming way in and you have Pixel Grid turned on as an option in the show options of the View menu?
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Thanks for your reply, Jeff.
Unfortunately, the patterning is visible at 100% zoom and is independent of whether I have the View>Show>Pixel Grid checked or not.
Stranger still, the patterning disappears if I convert the file from 16 to 8 bit.
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Well, it must be you. I can't duplicate it...
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I can. It happened to me today for the first time. I put it aside to deal with later, as I was already up to my ears trying to sort out the Disappearing Drop-down Menus in Curves Layers After Using Crop Tool bug.
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A little more information:
Converting the 16-bit file to 8-bit will remove the patterning, as will converting the file to another mode (Greyscale, Lab, CMYK).
If I create a new layer that duplicates the rotated layer, the patterning disappears (unless you reduce Opacity).
Saving the 16-bit file as a TIFF or .psd will preserve the patterning. Saving it as a JPEG will remove it.
The patterning is not camera-make-dependent: I can replicate the effect with both Canon and Hasselblad files.
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I can't duplicate (CS6 32 bit, 5x7" 360 dpi new doc w. white background, fill with black, straighten @ 40 degrees & accept, zoom in from 100% to max), same with 8-bit and 16-bit file.
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For me, the effect is only obtainable with rotation of 16-bit files. If I start with a new 5x7" 32-bit file at 360 ppi and RGB, then rotate and accept, and then convert to 16-bit, there is no patterning. But if I convert my 32-bit file to 16-bit, and then rotate, I get the same old patterned noise.
As I like to work with lots of shadow in 16-bit, this is a bit of a nuisance. I have not yet made a print to see if the gentlemen's suit patterns reproduce on paper.
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I can reproduce this. With a 16 bit file I get the pattern, with an 8 bit file I don't.
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All I get is the pixel grid pattern when zooming far enough, for me that' 500%.
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This is some kind of issue with the video card I imagine. I get the pattern on my Thinkpad laptop but not on my desktop. A patterned file made on my laptop exhibits normally on the desktop machine or even in CS5 on the laptop. It only seems to be the crop tool rotation too, Image>Image Rotation>Arbitrary does not cause a pattern. Both systems are 64 bit.
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Problem 'explained'!!! Yes, the video card is indeed implicated.
Go to Preferences>Performance. If under Detected Graphics Processor, you have checked Use Graphics Processor, then the 16-bit file crop/rotation weirdness will occur as described above. If you leave it unchecked, then restart PS6, the gentlemen's suit patterns will no longer appear upon cropping/rotating.
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Mine's been checked since I installed it.
Nvidia 560ti card, custom PC.
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Mine's an ATI Radeon HD 4870 on a MacPro (early 2009 variety).
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Mine's an ATI Radeon HD 5800 and I get the patterns - so it looks like an ATI issue?
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Hmmm ..... I've also posted this 'problem' on the Adobe Photoshop forum, and it has received the attention of an Adobe representative. We'll see!
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It's not an ATI issue, I have the problem with my Thinkpad laptop and that's got an Nvidia 570M in it. I installed the latest driver, since the original one was quite old, and that reduced the effect but did not remove it.
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Has anybody found a workaround yet for this intensely irritating bug?
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Adobe know about it, but I've heard nothing further.
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Adobe (http://forums.adobe.com/message/4520249#4520249) now say they cannot replicate the problem, but that it might have to do with the video card. Another contributor asked me to post full system details via PS>Help>System Info. I have done this, but of course I am not the only person with this problem, so it might be useful if others afflicted by this annoyance chime in on the Adobe forum too.
For an example of the patterning, download the psd file (1mb) at http://www.erickellermanphotography.com/pattern.psd (http://www.erickellermanphotography.com/pattern.psd)
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OK, with thanks to people on the Adobe Forum and our very own Artobest, I think the problem lies with the checking of the 'Use Graphics Processor' in Preferences>Performance. If UGP is checked, and then when the Crop tool is used, 'Delete Cropped Pixels' is NOT selected, rotation with the Crop tool leads to the patterning. If UGP is not selected, and PS6 then restarted, it does not matter whether 'Delete Cropped Pixels' is selected or not.
I would be very grateful if people so far unaffected by this problem and still following this thread would attempt replication under these conditions.
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The discussion on the Adobe forum (http://forums.adobe.com/message/4522418#4522418) is ongoing and evermore fascinating. Frankly, it's now too technical for me.
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Frankly, it's now too technical for me.
+1!
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But at least we have the ear of a senior Adobe engineer ...
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But at least we have the ear of a senior Adobe engineer ...
... Chris Cox, who writes: "This topic is talking about a major problem that makes low bit errors visible on some GPUs when they should not be visible.
We need to get a reproducable case of this so we can figure out where the bug is (in Photoshop, in the driver, etc.) and get it fixed."