Color change after flatten?

[steve_peters@adobeforums.com]

I am using CS on OS 10.3.3. I was working on an image that had about 20-30 layers, about 10 of those where verious color correction layers. Curves, hue & saturation (I used the blend if option to restrict this layer to just the shadow), etc. Some of these layers may have had different blending modes. I have beed using Photoshop since 2.0. I seem to rember this happening to me once before several years ago, but I can not recall what was causing this. Anyone have any ideas?

[Mark McIntyre]

Try doing a "Duplicate Image" with merge layers selected.

[steve_peters@adobeforums.com]

I tried that, and it still changes color. The change is slight, but noticable.

[Mike_Ornellas@adobeforums.com]

the facts of life.

[Doug_Katz@adobeforums.com]

Two other options:

1. Make a new layer > option-Merge visible (from the flyout menu). It'll fill your blank layer with a composite of your layers. Is the color preserved?

2. Duplicate the layered document > one at a time, select pixel layers that have adjustment layers altering them and command-E to merge them one by one > after all are merged, flatten the file. Any better?

[steve_peters@adobeforums.com]

Ok. So I tried what Doug suggested and I still am having some color change. I did go ahead and just start merging down one layer at a time, and I found that it was just or normal curves adjustment layers that would cause the slight color change. There was no special blending mode or anything. I found that merging one layer at a time I still ended up with the same color. I also noticed that if I zoomed into %66.7 you could not see the color change, but I just assumed that this was because I was looking at a much smaller part of the image. The image is of a car shot on a road that is covered by trees. So there is alot of variation of color an luminosity in the leaves.

[Ann_Shelbourne@adobeforums.com]

Are you looking at this at 100% (View/Actual Pixels) and do you have a true Background Layer?

Do you see changes if you "Merge-up" into an empty layer while viewing at 100%?

[steve_peters@adobeforums.com]

I do not see the color change at %100. But I feel that this is do to the fact that I am only seeing a very small portion of my image. As I said above, this is a shot of a car in some trees. I am only seeing the color change in the leaves, and a little on the trunks of the trees, but not on the car. I notice slightly less yellow over all and small decrease in saturation. This image is roughly 8.5x11 at 480dpi. So when I zoom in at %100 I am only seeing a very small portion of the image. I have tried merging up and still see the change when I am zoomed out. It has been suggested that it is just the way that Photoshop handles images that are at anything but %100. I can believe that, but I have been using Photoshop since 2.0,, and I can only remember this happening 1 other time back in 6.0. I do not recall the circumstances of that image though.
I just did a test and placed some eyedropper points in the area's that I saw the change, and the numbers did not change. So then the color change is being caused by the preview. But why this image? I am working in 16bit, so that is something new for me. Has anyone else experienced this?

[Ramón_G_Castañeda@adobeforums.com]

Steve,

When you are looking at an image at 100% you are looking at the actual pixels. At any other resolution Photoshop and any other application will have to interpolate or average neighboring pixels. The color change is inevitable, expected and natural. That's why 100% is there.

[John_Slate@adobeforums.com]

Since this only seems to be a display issue, what this implies to me is that the Merging-up, or stamping, provides no real advantage over simply flattening.

[Ann_Shelbourne@adobeforums.com]

Merging-up has several advantages:

It lets me have a number of such layers (with different content) that I can make visible at will so that I can "Place" (and embed) any one of the variations in different Illustrator files.

I can also USM the stamped layer without affecting any of the underlying layers.

[Doug_Katz@adobeforums.com]

John isn't doubting the convenience of merging; he's questioning whether it preserves the appearance of color, tone, blend modes, opacity, and so forth any better than image flattening does.

JS, I'm not smart enough to understand WHY under certain circumstances merging preserves something that flattening disfigures - and, worse, I can't recreate the specific image conditions under which merge and flatten produce different results. But I'm quite sure I have seen (even at 100% mag) certain blending effects and layer style appearances altered by flattening (sometimes because there isn't a true background layer in the image, sometimes for more mysterious reasons, more often with grayscale tones than color for some reason). In these situations, I've been able to protect appearances by either merging into a new layer, merging individual pairs of layers at a time, or even duplicating the image with "merged" selected (which is especially strange since this action is suspiciously like flattening... but I don't think it actually flattens the duplicate to a true Background layer).

You're entitled to specific examples. I wish I or someone else who believes what I'm saying could supply them. I'll keep my eyes open.

[Mike_Ornellas@adobeforums.com]

Doug,

when you compile massive amounts of color edits, things are going to break from an engineering standpoint. It is truly amazing that the stuff works as well as it does, but the simple fact that a flat file "should" look like a layered document is a real concern.

Let me just say that......... "there aware of it"

[Doug_Katz@adobeforums.com]

Got it, Mikey. I actually am not really concerned about this issue... mostly 'cause I've found the workarounds that I mentioned above. I was just trying to convince John that merging really does protect certain appearances under certain conditions that wholesale flattening doesn't. Problem is, I can't be real persuasive 'cause I don't understand the technicalities enough to reproduce the circumstances for him.

[Mike_Ornellas@adobeforums.com]

It's a real issue for me Doug due to the type of work I do.

[Doug_Katz@adobeforums.com]

Understand that completely, Mike.

[Ann_Shelbourne@adobeforums.com]

I imagine that this phenomenon has something to do with the order in which the mathematical equations for the different adjustments and layer-modes are compiled -- depending on whether you are merging up or down.

I have definitely noticed the difference in the past so I adopted the merging-up technique and now I always "merge-up".

[John_Slate@adobeforums.com]

Well that's good enough for me.

Even though I have never seen the problem, I can accept that it exists.

As a printer, I guess I don't really do that much work on complex layered files, so it's not surprising that I don't bump up against this.

Then again there is the flattening that ID does to consider...

[Mike_Ornellas@adobeforums.com]

hmm..

[John_Slate@adobeforums.com]

Oh geez, I've been "hmm...ed"