2004.01.15 17:37 "Re: [Tiff] COLORMAP and byte padding", by Andy Cave
I think that both methods are fine, depending on what you want to do. The /256 gives an equal spread of resultant values (visually better), where /257 does not. /256 is much faster than /257 (or the macro). /256 gives larger 'errors' to the floating point value (but the error is small - diff is 20/65535). When doing an equal spread, it is pretty obvious that the max 'error' is 255. The difference between the mean error is neglible. This error is also /65535, so is always pretty small. Personally I don't see the need to use one over the other (they are both pretty much as accurate as the other), so would go for simplicity and speed.