2004.01.23 19:15 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Bob Friesenhahn
In the remote sensing community we used (still?) sometimes call what is a "sample" in TIFF a channel. Apparently it originally had something to do with comunications channels to the satellite or something. Band is another
You are biased by your remote sensing background. A sample is just a sample. A sample is one unit of data. Multiple samples can be used to support image rows, strips, tiles, or planes.
The notion of "channels" is a way of thinking about raster images as being comprised of one or more layered "planes". So the term "channel" is similar to a "plane". Some interpretation of the available (or selected) channels is used to compose the image that a viewer actually sees. For RGB hardware, the red channel occupies the red channel of the hardware, etc.
So, a channel is a collection of all of the samples which have the same meaning.