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Other software unable to display .tif files created by GIMP
#1
Canon supplies software that can be used to edit photos produced by Canon cameras.  Since GIMP does not support the development of raw files this software performs a necessary function, even, for those of us who desire using GIMP for lots of our editing work.  This Canon software also provides some powerful printing capability that is quite lacking in GIMP.  However, it turns out that files created by GIMP in .tif format cannot be processed by the Canon software.

While I'm sure this is the kind of problem that temps everyone to want to blame the other guy, there is something amiss here.  When it comes to GIMP, I'm not aware of any other software that cannot handle the same files that Canon Digital Photography Professional (DPP) is having a problem with.  Whereas DPP is handling files produced by other programs such as Rawtherapee without any difficulty.  In the case of GIMP it doesn't seem to matter whether problem files are of 8 or 16 bit precision.

Any ideas on what is going on here?
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#2
TIFF is not that well defined as a format, and is a catch-all for many formats (Canon's own CR2 is a TIFF derivative). when yoiu export as TIFF, there are 5 different formats to choose from (excluding the Fax formats). Which one(s) is/are not recognized by DPP?

PS: You can use RawTherapee (and others) as Gimp plugins to have Gimp edit RAW files (but IMHO it's not a good idea, best keep Raw and Gimp editing separate).
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#3
After a little more investigation I've now found that Canon DPP is not the only image editing software that CANNOT open files created by GIMP in .tif format.  Arcsoft Photo Studio 6 (PS6), which was included with my scanner, is also unable to open some such files.  I've also done a few tests to try and determine whether or not this phenomenon is related to any specific options that might be associated with the faulty .tif files.  It turns out that in at least one such trial PS6 seemed to be troubled by the assignment of an ICC profile.  In that, it could read such a file that did NOT contain an ICC profile.  However, DPP cannot open any .tif files that I've created with GIMP which includes quite a few.  This certainly is NOT conclusive but does mean there is evidence suggesting that this problem is caused by GIMP.

While I'm a bit of a novice, I've come to understand that what photographers like about .tif format is the widespread support of the standard that makes such files universally compatible (or now I'd have to say almost universally compatible).  One would think this is a problem that ought to concern both GIMP users and developers.

(12-18-2018, 09:34 PM)Ofnuts Wrote: ... Which one(s) is/are not recognized by DPP?

PS: You can use RawTherapee (and others) as Gimp plugins to have Gimp edit RAW files (but IMHO it's not a good idea, best keep Raw and Gimp editing separate).

If, by format, you mean the different compression options the answer is that I gave up on using compression because of compatibility issues.  Therefore the files I'm referring to specified "Compression - None".

My lack of interest in using GIMP plugins might be attributed to advice you've provided in other posts in the past.  My current understanding is that the plugin would have to perform at least minimal developing of the raw data.  If I were to try it I'd definitely want to know what kind of data GIMP was receiving.  Might it be in .tif format?  What precision?  If it is .tif why not create a file that becomes a known artifact?

Truth is, at present, I wouldn't be wanting to use DPP to edit a .tif but my desire to produce .tif is pretty much all about compatibility.  However, printing is something I am struggling with and Canon Print Studio Pro has a lot of capability that is missing in most other software.  I've also been using Picasa for printing which is a program that has some nice usability features but I'm feeling a need to rid myself of reliance on Picasa.

If someone knows of a good way to print, with my Canon Pro 100, I'd love to get some advice.
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#4
If you are using a plugin there is no format, Gimp receives the layer directly.

Can you create a small TIFF with DPP (crop any image to 100x100) and attach it here?
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#5
(12-19-2018, 08:56 AM)Ofnuts Wrote: ...

Can you create a small TIFF with DPP (crop any image to 100x100) and attach it here?

Well now this exercise forced considerable experimentation.  It now looks to me like there are lots of ways to make .tif format files with GIMP that DPP is able to open.  This finally lead me to a case that fails.  I tried lots of combinations of exporting a single layer image with both 8 & 16 bit precision as well as with and without ICC profiles assigned but couldn't recreate the problem.  It took adding a second layer in GIMP, which is something that I do on most images that I export from GIMP, to reproduce the problem.

I attached 2 fairly small sample files.  They are the same except that a second layer was added in the one that says "Layered" in the file name.  It is the one with the added layer that exhibits the subject defect.


Attached Files
.tif   IMG_0237.PelicanSmall.16bit.RT54.ELLE-ICC.Layered.tif (Size: 839.56 KB / Downloads: 213)
.tif   IMG_0237.PelicanSmall.16bit.RT54.ELLE-ICC.tif (Size: 604.93 KB / Downloads: 217)
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#6
Maybe check if other software is able to open a layered TIFF from Gimp? Is there a difference when all layers arethe sale size as the image or when one layer is smaller (and is not in the top left corner)?
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#7
Further experimentation indicates that if I import the defective .tif file created by GIMP into Rawtherapee and do nothing but export it in the same .tif format the defect is removed and the file works fine in DPP.

Another interesting observation is that when I took one of my files that provoked this initial post (i.e., the problematic .tif created by GIMP) was about 80MB in size.  After remaking it with Rawtherapee the resulting (i.e., so far non-problematic file) is about 60MB in size.  Obviously if the same thing is only 3/4 of the size that is also an improvement.

I'm certainly not sure what accomplished photographers would think of making such a maneuver but even if thought to do no harm this would not be very handy.  I'd think that GIMP should prefer being handier to use.

(12-19-2018, 08:50 PM)Ofnuts Wrote: Maybe check if other software is able to open a layered TIFF from Gimp? Is there a difference when all layers arethe sale size as the image or when one layer is smaller (and is not in the top left corner)?

Of course the amount of other software that I am able to test is very limited when compared to a fairly large universe that is needed to achieve compatibility.  However, I can confirm that Photo Studio 6 will NOT open the attached layered sample.  I often use GIMP to add a layer that is larger than the image with negative values for the offset in order to center the image within the new layer.

I'll do some more experiments to see what happens with same size layers as well as layers with same upper left position.  Let you know what I find later.  I could also try some text layers that reside within the image layer.
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#8
Three more trial images, in .tif format, all exhibit the same defect that is the subject of this topic.  All had an added layer as follows:

  1. New layer larger than the original image but with zero offset (i.e., top left corner in same place)
  2. New layer the same size as the original image
  3. New layer smaller than original image but with positive X & Y offset where added layer was still completely covered by original image
Of possible interest.  I'd previously posted a topic on the Canon forum regarding this problem which didn't result in much of any explanation.  However, at about the same time I was posting this topic on this forum that topic on the Canon forum received a reply from someone else experiencing the same problem.  It turns out that Photoshop was used to create the problem image in that case.  I've never used Photoshop and don't know much about it but, I THINK, it is also a layered editor which is something it has in common with GIMP.  GIMP and Photoshop would be the only layered editors I know about and I also think it might be fair to say that layered editors are much more rare than non-layered.

I'll be glad to attach the new images if desired.  They are the same original image but a little smaller because I also went with 8 bit precision instead of 16 bit.  Let me know if you want any of them.
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#9
I was reading up on TIFF files a while back, and this topic reminded me of this part: "When TIFF was introduced, its extensibility provoked compatibility problems. The flexibility in encoding gave rise to the joke that TIFF stands for Thousands of Incompatible File Formats. To avoid these problems, every TIFF reader was required to read Baseline TIFF. Among other things, Baseline TIFF does not include layers, or compressed JPEG or LZW images."
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#10
Finally stumbled unto what appears to be the cause of this problem.

It seems that the troublesome files were ones where the GIMP editing involved creating some extra layers which adds an alpha channel, which is something I really don't know much about.  However, when you export such an image the .tif format supports inclusion of the alpha channel, which now appears to be what was causing the problem.

When exporting in .tif format there is an option called "Save Layers".  It seemed to this novice that disabling this meant just give me an ordinary single layer image which is what was desired.  However, doing that is NOT enough as it seems an alpha channel gets preserved.  By first using the "Flatten Image" option in the layer dialogue the alpha channel/s get removed and the problem that provoked this post goes away.  This makes it look like this is what Rawtherapee was doing when reexporting the problematic file.

This method of operation presents a slight usability problem that requires the exercise of some care.  If, like me, the motive for retaining an .xcf file is to preserve the layers it becomes necessary to "Flatten" before export but then "Undo" the flatten or possibly exit without saving in order to retain the desired multi-layer file.
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