2018.05.11 17:55 "Re: [Tiff] Question about transfer function", by Kemp Watson

That's easy... not really part of TIFF, but _in_ TIFF at least: define a tag to hold a JSON object, for example (or YAML/TOML/XML etc if you're so inclined).

Would be nice to make it official... but we can't do that :)

K.

On Fri, May 11, 2018 at 1:39 PM, Larry Gritz <lg@larrygritz.com> wrote:

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.