2018.05.11 17:39 "Re: [Tiff] Question about transfer function", by Larry Gritz

On May 11, 2018, at 9:43 AM, Olivier Paquet <olivier.paquet@gmail.com> wrote:

That's more or less what we chose to do several years ago but on a smaller scale (only a handful of built-in spaces supported). As there was no tag for it, we stuffed the information in TIFFTAG_IMAGEDESCRIPTION. I'm not saying it's great... but embedding the whole thing into each single image is indeed not great either. I like the idea of a dedicated tag to reference an OCIO color space.

Yes, indeed, there are already a couple pieces of important metadata that I just shove into the ImageDescription and then parse it on the other end, but generally I only do this for textures, where I know it's my own apps that are the only readers that matter.

I've hesitated expanding how much I do that generally, knowing that most tiff readers won't recognize it, and it's probably also confusing to apps who actually expect a caption or image description to be there. But I suppose that as the percentage grows of readers and writers that exclusively access image files through my library (in the VFX field, at least), I can rely on that more. But it's not nearly as attractive as dedicated tags for the most important items. It's a true weakness of TIFF that it does not allow for arbitrary named metadata.

--
Larry Gritz
lg@larrygritz.com