IM Thumbs of Photoshop Files w Layers

[StanRohrer]

IM 5.2.14 seems to not render thumbnails nearly as well as IM3.6. In IM3.6 the layers were included in the thumbs views as saved in the file. In IM5 I'm not seeing the backgrounds as I have set. Is there a setting I need to adjust or is IM5 not as good with layered PSD files? Screen captures attached.



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[Ferdinand]

This has been discussed once before.  It's surprising that it's only been once so far.

https://www.photools.com/community/index.php?topic=978.0

[StanRohrer]

In the other thread Mario asked for a sample file. I have attached a heavily size reduced file here.  Play with the layers White Fill, Gradient, Background for the most obvious IM5 views.

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[Mario]

This image has an alpha channel which is used to isolate the image of the truck. At least that's what the image library reports when IMatch asks if the image has an alpha channel. IMatch then interprets this alpha channel and renders the transparent area using a checker board pattern. This behavior is by design.

When you disable the option "Save alpha channel" when saving the PSD file (in the File dialog) the image be saved without an alpha channel (makes not difference in Photoshop itself AFAIK) and the image will this render correctly in IMatch 5.

Left: Your file.
Right: Same file but saved with "Save Alpha channels" option disabled in the "File Save" dialog box.





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[Carlo Didier]

This is something that's been annoying me for a long time, but the number of files concerned is rather small for me, so I didn't insist much.
The problem is that there are perfectly good reasons to save alpha channels from selections which are not meant to be interpreted as transparency masks (as Ferdinand explained in the other thread) and then there are transparency masks.
iMatches Problem is that it can't distinguish between those cases. I think it should be technically possible (as other applications obviously can do it), but I don't know whether Mario can influence the behaviour of the third party libraries he uses to that extent.

[Ferdinand]

Mario's point is that this is an unavoidable consequence of displaying transparency.  His point is that you either display transparency and have the problems like you see with Stan's truck, or you display Stan's truck correctly and don't get transparency.  I am not in a position to dispute that statement.  Nor am I in a position to say which is preferable for the wider IMatch user base.

It's been some time since I looked at this.  While it's true that some other programs display Stan's image correctly, can they display transparency for images that have it?  I'm not sure that they can.  If not, then it's understandable why IMatch can't do both.  If they can, then it opens the possibility that it could be done.

I also seem to recall that this is an issue with TIFF.  I don't think it happens with PSD.  I prefer TIFF since it's supposed to be open, although IIRC (if I recall correctly), the TIFF standard is not as open as you might think, as it's now owned by Adobe, is it not? 

Telling people to delete the alpha mask they worked so hard to create is still poor advice.

[StanRohrer]

I will have to play with the Photoshop Save Alpha Channel. But my intent is to keep paths as they currently appear in the output JPG files. File buyers use the clipping paths in their work and they are worth sale money to me.

My point is that IM3.6 shows the files as I desire and IM5 does not. The first post images are of the very same files in the very same folder (a single save from Photoshop) as scanned by IM3 and IM5. My preference is IM3 because I have similarly Photoshop processed files in IM since 2003 and the display has worked to my liking since then.

[Carlo Didier]

I may have found a workaround that's quite easy to implement.
If the top additional channel (the first below the RGB channels) is filled with white, then the preview is correct, with no transparency.
There seems to be no difference if you use TIF or PSD. In the attached example, Test-1.* are without and Test-2.* are with the "dummy" channel.

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[Mario]

My point is that IM3.6 shows the files as I desire and IM5 does not.

IMatch 3 did not interpret alpha channels. IMatch 5 does, because it was so often requested.
Can't have both, sorry.

When I look at your sample PSD, it has an alpha channel (because you use that option when saving it, and that means that PS writes a composite alpha into the file). And IMatch reads the alpha channel and applies it. If you want explicit options for ignoring alpha channels in IMatch 5, please add a feature request. Since this specific problem was reported once a while ago, and now again by you, there may he a few users who consider this a problem. They can then comment on your feature request, +1 it etc.

It will not be hard to implement, but I expect at least one or two days for the UI, the internal updates to the logic, documentation etc. Quite a lot of work so I need to make sure that more than a handful of users will benefit from this. Otherwise the two days are spent better on other things.

[Ferdinand]

If the top additional channel (the first below the RGB channels) is filled with white, then the preview is correct, with no transparency.

There seems to be no difference if you use TIF or PSD.

Workaround is neat.  Sorry that my recollection re PSD was faulty.  I guess there is still the question about whether there are programs that can both display a file with transparency and also display a file with a saved alpha mask correctly. 

[StanRohrer]

Photoshop CS5.1 does not willingly save the master .PSD file with Alpha Channels unchecked. It wants to only save a copy file so the copy looks OK in IM5 but the master still has the transparency issue.

[StanRohrer]

I may have found a workaround that's quite easy to implement.
If the top additional channel (the first below the RGB channels) is filled with white, then the preview is correct, with no transparency.
There seems to be no difference if you use TIF or PSD. In the attached example, Test-1.* are without and Test-2.* are with the "dummy" channel.

Can you try this with the sample truck file in the third message from the top? Any tips appreciated as I don't work with alpha channels!

Here is what I ended up with and it did seem to work for any of my multiple backgrounds.


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[StanRohrer]

Feature request added on that forum:
Option to Ignore Alpha Channels
https://www.photools.com/community/index.php?topic=3839.msg25620#msg25620

Please indicate there if you desire this option.

[Carlo Didier]

Can you try this with the sample truck file in the third message from the top? Any tips appreciated as I don't work with alpha channels!

You got it right, except that you still had a selection active (the channel named "Cutout Mask") when you did the screenshot. You must not have any selection active when saving the file.

[StanRohrer]

Note that Mario has added a Edit / Preferences / File Formats selection in 5.2.18.  See here:
https://www.photools.com/community/index.php?topic=3839.msg25620#msg25620