2006.10.17 13:27 "Re: [Tiff] Tag 346", by Ross Presser

On 10/17/06, Leonard Rosenthol <leonardr@pdfsages.com> wrote:

Doesn't matter for the OP's purpose (as he explained).

If the actual values of the colormap/index table don't matter - then why not ignore it completely and simply treat the image as grayscale? The data for an indexed color image is 100% equivalent to the data for a grayscale image - just an array of values (1 per pixel).

The data are not quite equivalent; the colors do have semantic meaning in this context -- it's important to know which pixels are magenta rather than black, and the magenta and black pixels are not shades of the same tint. It may work as an intermediate format. It would look rather odd on screen, though, as a grayscale image, since the three palette entries would correspond to gray levels that were very very close together: 0, 1, and 2. I would have to expand that, maybe to 0-127-255; and if I'm going to do that manipulation, why not go a little further and use a format that might actually look like something on screen, i.e. indexed RGB color, using #000000, #FFFFFF, #FF00FF?