Photoshop Elements 10: TIF thumbnail sometimes incorrect in Windows XP Explorer

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  • Updated 6 years ago
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  • (Edited)
Sometimes when a TIF file is saved (with “Discard Layers and Save a Copy” selected) the thumbnail shown in Windows Explorer is incorrect.

The thumbnail appears to show only one layer from the PSD file that was being worked on, even if that layer no longer exists because it has been deleted or the image has been flattened.

I have experienced this problem in Elements 7, 8 and 10, and on a machine with a fresh install of Windows XP. I have reported this problem to Adobe on two previous occasions, so am disappointed that the bug persists in the latest version of Elements.

I can supply a PSD file that demonstrates this problem if required.
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Ian Eveleigh

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Posted 6 years ago

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Brett N, Official Rep

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Could you list an exact workflow to reproduce this?

How did you report the issue previously? I'd like to look it up and see what has been said before and what work has been taken toward resolving it.
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Ian Eveleigh

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A typical workflow that may create the problem is as follows:

1. Open a photo (can be a tif, jpeg or raw file - the problem has happened with all of them).
2. Create a series of duplicate layers, each with changes to the photo (e.g. one for cloning/spot healing, one for shadows/highlights adjustment, one for sharpening and noise reduction). On some of these layers I may delete parts of the image to make adjustments only to the parts that remain. I will then use the Stamp Layers function to create a new layer from the layer with areas deleted and the layer below it.
3. Add adjustment layers (levels, hue/saturation, etc.)
4. Save as a PSD (I may also have saved the PSD at an earlier stage).
5. Save as a tif, with "Discard Layers and Save a Copy" selected.

Unfortunately, the problem doesn't always happen, and I can't see any pattern in what I'm doing that makes it happen sometimes and not happen others.

When it does happen, the layer Elements chooses for the tif's thumbnail will be one of the layers I have created in step 2. What usually makes it obvious that it has happened is if the layer Elements choeses is one of those with a large part of the image deleted. Perhaps the problem happens more often, but if the chosen layer doesn't have areas of the image deleted, it wouldn't be as obvious.

Once Elements has decided that a particular layer should be used for the tif thumbnail, it will continue to use it as the thumbnail, even if the layer in question has its visibility toggled to off, or the layer is deleted, or the entire PSD file is flattened.

As mentioned, I can supply a PSD that has this problem. Presumably there will be something in this file that will reveal why it continues to choose a particular layer as the thumbnail, and why the thumbnail doesn't get updated as the PSD file changes (e.g. if the image is flattened).

Regarding reporting this problem, I can't remember how I reported it the first time, but the second time was via the Customer Support Portal (using this ID). No steps were taken to resolve it.

Many thanks for looking into this - a fix would be much appreciated!
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Brett N, Official Rep

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Please send the PSD file to bnemecek [AT] adobe [DOT] com. I'd like to test it on my side.
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Ian Eveleigh

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PSD e-mailed.
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Brett N, Official Rep

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Received, will test.
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Brett N, Official Rep

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I'm able to reproduce the issue with your file. I see that it happens in Photoshop CS5 (as well as some older versions as well). I'm going to continue testing.
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Brett N, Official Rep

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Looks like the "problem" here is that there is an Alpha Channel in this PSD and it is being applied to the the image thumbnail. This is actually as expected for TIFF files.

Photoshop Elements doesn't work with Alpha channels directly, like Photoshop does. However, this should resolve your issue with this file, and files like it in the future: Go to Select > Delete Selection...

When you save a selection to an image in Photoshop (Elements too), that selection is saved as an Alpha Channel. If you save the file, that Alpha Channel is read by the OS and applied to the thumbnail.
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Chris Cox

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In other words: the file is fine, XP doesn't show the preview correctly (someone failed to read the TIFF spec.), and Elements makes it harder to see the alpha channel in the document that's confusing XP.
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Yoon-Hee Cha

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Thank you so much for your posting Brett N. I've been dealing with this "remove alpha channel" issue all day to submit figures for a paper and I finally found your note---which solved the problem. What's confusing on Adobe Elements 10 is that there is nothing on the dropdown menus that is called a "channel." And, the HELP function doesn't pull up any hits when you search for alpha or channel. Thank you!
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Ian Eveleigh

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Nice work on spotting that the saved selections contribute towards this issue. At least now I know that by deleting them I can get a "good" thumbnail. Not perfect, but at least it's a workaround.

Interesting theory that XP is to blame here. But if this is the case, I'm confused by a couple of things:

1) Why, when I copy one of these tifs to an iMac (running Mac OS X 10.6.8), does it still show a "bad" thumbnail?

2) Why, when I flatten all the layers in the PSD (or delete all the layers apart from the original photo on the bottom layer), then save the file as a tif without layers, does it still have a "bad" thumbnail? Surely in these circumstances there should be no Alpha channel data being applied to the image and therefore no Alpha channel data being applied to the thumbnail?

From my point of view, it looks as if Elements is incorrectly applying Alpha channel data from whatever saved selections are present in the PSD, regardless of whether they are being used on the image...
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Chris Cox

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Saved selections/alpha channels are something we know about and have reported to Microsoft for them to fix.
If there are problems *without* alpha channels, that's something we need to know how to reproduce.
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Ian Eveleigh

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I'm still confused...You said earlier that "If you flatten the image, this particular OS bug with alpha channels shouldn't be a problem." The steps I gave above do create a flat image, i.e. an image with one layer. (If it helps, you can add another step "5b: Flatten Image", not that it will do anything.)

If that's not good enough, try flattening the PSD file I sent to Brett N for testing - it still produces a "bad" thumbnail, while your earlier comment suggests it shouldn't.
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Chris Cox

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If there is an alpha channel, then the known OS bug can be a problem.

Yes, Apple and Microsoft both misread the TIFF spec, in slightly different ways. We can't do anything about their mistakes without breaking the TIFF spec. and breaking compatibility with hundreds of other applications. We can't "fix" their mistakes.
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Ian Eveleigh

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Fair enough. I can see that you wouldn't want to break the tiff spec.

However, the situation is still confusing to the Elements user - even one technically minded. How exactly are we supposed to know that saved selections are treated as alpha data and applied to the tiff? Personally, I would expect saved selections to be purely an Elements thing, i.e. saved with the PSD file, so they are there if I wish to use that selection again; I wouldn't expect them to be saved with the tiff file at all.

Perhaps one solution would be if Elements could include a simple option, selectable either upon saving a selection or upon saving a tiff, that dictates whether saved selections are saved with the tif or not. Then at least those of us having this problem would have an easier workaround that wouldn't involve us having to delete our saved selections from the PSD.

After all, presumably both Windows and Mac OS have had this bug for some time, which presumably means Microsoft and Apple aren't likely to fix it any time soon!

Out of curiosity, is there anywhere I can read a copy of the tiff spec, particularly the bit about how thumbnails and alpha channels are handled?
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Chris Cox

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You don't - you just have to know that the OS thumbnails aren't always right. And you shouldn't judge content by the OS thumbnail anyway - it's a reminder of the content, not the actual content of the file.

TIFF doesn't specify thumbnails, but does specify flexible handling of extra channel data. MacOS and Windows build thumbnails by reading the full file, or sometimes reading EXIF thumbnails (a separate spec. for metadata).

See http://partners.adobe.com/public/deve...
Be warned, it is written by a developer and intended for developers.

(and the website lost TIFF supplement 3, again. @$%^@#$%@#% )