Change in tif files?

[Robert Schleif]

Was there a change in the file structure of tif files saved by PWP 8 in August, or possibly July? Files that I've saved from PWP before August can be opened by the Canon program DPP 4 whereas tif files that I've saved with PWP since late August cannot be opened by DPP 4. As I sometimes lag a bit in loading the very latest version of PWP, I cannot say exactly with what version or on what date the problem began.

[jsachs]

Not that I know of offhand.

[jsachs]

FYI, when you save a script or workspace script file, the PWP version that created it is recorded in the header. If you open the file with Notepad, you can easily read it.

[tomczak]

TIFFs can be saved as 24 or 48 bit and also uncompressed or compressed with 2 different methods. I recall that I had a problem with some combinations of TIFF bit depth and compressions in DPP but I forgot which ones.

Maybe you could save an image in PWP as 6 different TIFFs (2 bit depths * 3 compression modes) and test if DPP has trouble opening any of them to try to pinpoint the problem?

[Robert Schleif]

Thank you for the information and suggestion. I think it best to ignore the problem as the number of images involved is small and it is not hard to bypass the problem and as the latest versions of PWP and DPP 4 do not display the problem. (One amusing tidbit is that if I reopen with the latest PWP one of the images that cannot be opened by the latest DPP 4, modify it, and resave, it still cannot be opened by DPP 4.)

[jsachs]

It may be related to some of the metadata in the file. You might try saving without the metadata to see if that fixes it.

[Robert Schleif]

I tried various combinations with the metadata, but this seems not to be it.
What I have found is that the problem is related to conversion to monochrome. Using PWP 8.0.241 I can open a tif file and save it and the written file can be opened by DPP 4. Using either the Crop or Brightness transformations on the file and saving still produces a written file that can be opened by DPP 4. However, if I convert the file to monochrom and save, the written file can no longer be opened by DPP 4.

[tomczak]

It looks like DPP can read 48 bit TIFFs but not 16 (or 8?) bit ones. I'm sure you already know it, but if you covert an image to B&W in PWP, but then convert it and save as 48 bit, that may fix it.

[Robert Schleif]

No, that is not the problem. DPP 4 has no problems with 16 bit B&W images made, say, July 2020, but it does have problems with 16 bit B&W images made today.

[Robert Schleif]

I was wrong. It is the 16 bit vs 48 bit issue mentioned above. There is nothing wrong with PWP 8.