Anything that TIFF lacks can be added using custom tags. All people need to do is to agree on names and types for these custom tags that store the new informati

Anything that TIFF lacks can be added using custom tags. All people need to do is to agree on names and types for these custom tags that store the new information. This means any old app will still be able to work with such TIFF files and just ignore the information it doesn't understand. So the problem isn't solved but the answer is not coming up with yet-another-file-format. A good example of extending TIFF with tags is Pixar's PhotoRealistic RenderMan. It uses a TIFF flavor as a base for its mip-mapped textures. Such a TIFF contains a pyramid of layers of the image at different pre-downsampled resolutions and a bunch of custom tags, the renderer interprets when it reads such a file. However, I can use 'Open As...' in Photoshop and open this as a TIFF. I will simply get the highest resolution layer from the file. That's a simple and battle-proven example of why TIFF is indeed a great answer to the problem.