Why don't IFF files exported from Photoshop load into DPaint3 on an Amiga?

[Rob68K]

Even if I use the 'Amiga' option when I'm saving.

[vulture]

Iirc there were several revisions of iff for images. Maybe DPaint III can't read Photoshop's format cuz it's newer? Maybe try DPaint IV or V instead?

[hitchhikr]

I think it's because they are pictures like those that were created with DPaint MS-DOS which had some differences with the Amiga's version.

[fxgogo]

Interesting. What size is your picture and what colour mode are you using?

[Rob68K]

Originally Posted by fxgogo

Interesting. What size is your picture and what colour mode are you using?

Indexed colour.
16 colours.
It's a 16x16 tileaset arranged as 26x26 so..... 416x416 pixels.

[a/b]

Post one example (or upload to the zone). I've been using gimp for a while and it works fine, don't have PS...

[PerspexSphinx]

Which version of gimp are you using that can write out "iff" files?

[khph_re]

Is it definitely the amiga IFF version? Photoshop also supports Maya (Alias Wavefront) IFF image's.

I normally use Irfan View for conversion.

[Marcuz]

Used to be, Photoshop had a plugin file format for correct IFF import / export: https://eab.abime.net/showthread.php...201#post126201

I'm not sure if this is still the case.

That said, I've just tested the embedded IFF export (Amiga) of the current Photoshop, and I could load the image with no problem in both the DirOpus viewer and PPaint 7.1

I'll test DPaint in a bit

[Minuous]

Maya "IFFs" are not actually fully conformant IFF FORMs anyway; I don't recall the details but there is some bug in their header or padding.

[Marcuz]

I can confirm that I cannot load the image I used for test (320*256 indexed) in DPaint 3 and 4, I couldn't test 5.
Error: malformed or mangled IFF

[Minuous]

If Photoshop is using the same routines as it does for Maya files than it is probably a similar header/padding issue. I'm happy to take a look if you want to attach or zone an example.

[Marcuz]

here: https://eab.abime.net/zone/Senza%20titolo-1.iff

This was exported via the embedded IFF option.

I'll try to check if the pluging version still works and if there's any difference (there should be: it used to be fully compatible)

[edit:]

- I've found the plugin for Photoshop, "iff format.8bi" (last time I used it it was ~15 years ago :/ ) but when I tried to load it, Photoshop CC refused it, error: "IFF version not available". So I can't test it anymore.
- the IFF file I've uploaded in the zone, that opens in DirOpus and PPaint, but not on DPaint, doesn't open in Irfanview either, even with the "formats" plugin installed. This is odd. I've tested IFF files generated on the Amiga, and they load up correctly in Irfanview.

So, to the best of my understanding, the embedded IFF exporter in Photoshop is NOT the "iff format.8bi" equivalent.

[edit 2:]
see Thomas post below

[thomas]

Originally Posted by Marcuz

here: https://eab.abime.net/zone/Senza%20titolo-1.iff

This is a 24bit ILBM file. It cannot be loaded into DPaint before version 5.

Additonally the BODY chunk has an odd length but has no pad byte. Probably not needed for the last chunk, but could be a cause for rejection anyway.

[Marcuz]

Originally Posted by thomas

This is a 24bit ILBM file. It cannot be loaded into DPaint before version 5.

Additonally the BODY chunk has an odd length but has no pad byte. Probably not needed for the last chunk, but could be a cause for rejection anyway.

Of course, I'm an idiot: for whatever reason, I thought the export automatically converted it, and I had not noticed it wasn't the case when I loaded the file on Amiga.

Now, if I first convert it to 8bit and then export as IFF from Photoshop, it correctly loads both on Irfanview and also DPaint 3 and on.

So: please disregard what I said before. To the point: the process should work.

[Minuous]

Originally Posted by thomas

Additonally the BODY chunk has an odd length but has no pad byte. Probably not needed for the last chunk, but could be a cause for rejection anyway.

Yes, some readers might handle such malformed files, but the standard is quite clear that every odd-length chunk must have a padding byte.

[a/b]

Originally Posted by PerspexSphinx

Which version of gimp are you using that can write out "iff" files?

Correction: I'm using gimp + IFF plug-in.

[TCD]

If somebody needs a link: https://blitterstudio.com/gimp-iff-plugin/

[Rob68K]

Originally Posted by TCD

If somebody needs a link: https://blitterstudio.com/gimp-iff-plugin/

Yay!

oh. Windows. no Mac.

Anyway, after spending literally hours looking for a something that isn't Photoshop to load this file so that I might be able to save it again as something that DPaint would like, I decided to sweet-talk ChatGPT into writing me a raw converter* while simultaneously learning basic Python.

= Win.

* ultimately, the point - my own Amiga graphics converter doesn't like the file either and I don't have access to the source code at the moment to make the necessary changes.

[saimon69]

To avoid problems i usually go for middle formats like GIF and passing via ppaint; however most of the work i did port so far was in 16 colors or AGA