There are two major ways a color file is rendered, vector and raster.

A vector file, like those generated by Freehand, Illustrator, Quark, etc,
use instructions to draw lines (vectors) in an x-y plane (or in space if
working in x-y-z dimensions) and then tell an imagesetter, video screen or
printer how to stroke and fill that vector. So it doesn't matter whether the
stroke-and-fill information is spot, cmyk, rgb, etc - final flattening will
be handled according to the imagesetter's capabilities. (A film printer will
separate them because it can, your Epson inkjet will flatten it to CMYK
because that's all it can do.)

A raster file is pre-flattened into a mapped image defined by a pixilated
grid. There are no vectors. A layered Photoshop file is really a collection
of several tiff files; their 'vectors' (such as typography) are for
on-screen editing...they go to the imagesetter, printer, or page layout
program as flattened, rasterized art. Raster files will be either rgb or
cmyk, but that's about it.

in article bg9j88$a4u$1@forums.macromedia.com, Copeland Casati at
[email]copelandcasati@mindspring.com[/email] wrote on 7/30/03 7:09 PM:
> I'm curious- why does my 3 spot logo export as cmyk when I send it as a
> tiff, whereas if I send as an Illustrator file then it's ok?
>
> Thanks!
>