Dragging window in CS4 darkens image

8
Posted By
86
Mar 24, 2009
Views
1737
Replies
13
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Closed
Hi
Hope someone can answer this…

Why does an image darken while dragging the window within Photoshop CS4? Once the window is released with the mouse/pen, it snaps back to how it was?

Explained further:
Open an image in Photoshop CS4.
Click & hold the grey title bar at the top of the image. Move it around within the Photoshop window.
It noticably "pops" – darkens.
Release the mouse/pen, image snaps back to how it was.

Weird

I’ve put a sample point on a section of the image, numbers don’t change. I’ve tried disabling "Open GL Drawing"
– Doesn’t happen but…
– Image appears darker as per when dragging with "Open GL Drawing enabled. – Numbers remain the same on the sample point.

Hope this makes sense.

Here are some specs:

Photoshop V 11.0.1
Graphics Card: NVidia GeForce 7959 GT
Driver Verssion: 182.08 (latest)
Windows Vista Business, 64-bit (Service Pack 1)
8GB RAM

Thanks for any help
Peter
Related Tags
dark drag image window

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F
Freeagent
Mar 24, 2009
I have a hunch that the dark version may be the correct one. See this thread – especially Chris Cox’ posts:

<http://www.adobeforums.com/webx?128@@.59b85528>
F
Freeagent
Mar 24, 2009
That could be it, but I’m not sure.

What I do know is that OpenGL is "suspended" during the drag. You can check this by rotating the canvas, then drag it. It snaps back to the normal orientation until you release the mouse.

It’s also fairly obvious with an odd zoom percentage like 33.3%, where the image looks crisp (or jaggy) during the drag, and then snaps to the smoothed rendering on release.

This is why, until recently, I would have said that this is another OpenGL rendering problem. But according to Chris, it ultimately hinges on a faulty display profile. That’s how I read it anyway.

On a tangent, what I’d like to know is this: with OpenGL enabled, is the color conversion executed in the video card?
C
Curvemeister
Mar 24, 2009
I’ve noticed that in a two monitor display, a dragged image is displayed using the profile of the primary display during a drag operation. When the image is dropped on the final display, the profile of the destination monitor is used. If you have a two monitor system, that may explain what you’re seeing.
8
86
Mar 25, 2009
Thanks for all that.
Checked the link – Colour M’ment has gone a loooong way since my last course on it, way back in PS7!
Time for another course to get back up to speed I think.

Problem fixed by further exploring the OPen GL Advance settings. "Colour Match" was unchecked.
Activated that & all is sweet.

The link also explained the same problem I had with what looked great in LR looked average in PS CS4.

hmm…back to text books once I find time!

Thanks again
Peter
F
Freeagent
Mar 25, 2009
Glad you got it fixed 🙂

But I’m still curious about why this (or similar) happens to some people: Colors off in CS4 with OpenGL, but OK with OpenGL disabled or viewed in other color-managed apps.

Again according to Chris Cox, it’s because the newer color conversion engine in CS4, with some added features, chokes on certain (faulty) display profiles that previous versions didn’t have problems with.

But I still don’t understand where OpenGL comes into it. So to put my last question in post #3 more precisely: What exactly does the "Color matching" checkbox do? The tooltip says "perform color matching during image display", but that doesn’t tell me much. Does it do something that otherwise wouldn’t be done at all, or does it move some of the color conversion from the CPU to the GPU?
RK
Rob_Keijzer
Mar 25, 2009
Freeagent,

I was wondering that too. I even wondered if perhaps my colour management was corrupted when I leave the box off.

But this "Color Matching" box is inside an area that’s called Debugging, making me (photographer, not IT eng) think it can be off under normal use.

A while ago I deliberately made a corrupt screen profile using a Cyan filter between the screen and the Eye One Display 2 colorimeter, just to see if I still had CM, and indeed I had!

Up to now I don’t see any problems with the Color Matching box off, in correcting and soft proofing etc.

Rob.
F
Freeagent
Mar 25, 2009
Yikes! I see the same thing as the OP when I uncheck Color Matching. Saturation is drained out, and it gets slightly darker. In fact, it looks exactly the same as it would if I assigned sRGB to the ProPhoto-tagged file I was looking at. But there’s no question that it’s wrong, and that checked Color Matching is the correct view. It also snaps back to normal when dragging.

Now I really want to know what this box does.

Rob, you’re probably right about your Eizo in that things behave differently with a monitor LUT instead of a video LUT. But I’m still trying to wrap my head around what’s happening here. If it really is just a debugging tool, this should be stated in the tooltip, so people don’t mess with it.
RK
Rob_Keijzer
Mar 25, 2009
Ok, I did a little test.In Performance > Advanced Settings, I ticked Advanced Drawing and Color Matching.
Relaunch PS.
No colour change (tested with colour and B/W images, both ProPhotoRGB 16 bit).

Then I ticked "Use For Image Display", Relaunch, still no colour change, but moving the canvas with the Hand Tool and canvas rotation became somewhat jerky.

BTW In all tests I moved the canvas and also dragged image window.

Windows XP SP3; NVIDEA Geforce 8400 GS/PCI/SSE2; Eizo CE240W (single screen setup).

Would like to do same test with laptop (videoLUT) but OpenGL is disabled and can’t be enabled.

And here are my colour settings:

< http://www.pixentral.com/show.php?picture=1gEwk3izhBovLCJk8p eKFGyHz0Rl031>

Rob
F
Freeagent
Mar 25, 2009
Hmmm… I finally managed, at great personal risk, to get hold of a copy of the actual blueprints for the Photoshop Color Conversion Engine. I’m still trying to make sense of it.

< http://www.pixentral.com/show.php?picture=1eRSq7TedPMvdf1dvO DxJfSdT0wy16>
RK
Rob_Keijzer
Mar 25, 2009
Mmm, that looks suspiciously equal to the blueprint of a very sophisticated, and technically advanced toilet I invented in1974!

So now I know who stole it. Adobe!

Rob
F
Freeagent
Mar 25, 2009
toilet? That would explain it. XD
ZB
Zeno_Bokor
Mar 25, 2009
< http://kb.adobe.com/selfservice/viewContent.do?externalId=kb 404898>

Advanced Drawing: Allows the GPU to perform, and therefore speed up, certain tasks, such as color matching, depth conversion, HDR tone mapping, and checkerboard compositing.

Color matching: Can be used to avoid the display of visual artifacts.
F
Freeagent
Mar 25, 2009
Ah…it says move color matching to the GPU, I presume from the CPU where it was. So that’s part of my question answered.

Still not quite sure what "display of visual artifacts" means, but maybe it turns out to be not so important. I’ll play around some more with the settings to see what they do, even if I don’t understand why.

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