This may be a dumb question, and I am even sure that I knew the answer myself (if I remember the circumstances correctly, it was about 5 years ago).
If (for example) I have a colour image which has pixel dimensions of 1600 x 2400, then photoshop tells me that the image size is 11M, and for a flat image, the TIFF size is near enough this (10.9Mb). Fine. If (with my calculator) I work out 1600 x 2400 x 3 (RGB colour channels) I get 11.5 pixels. How can a file occupy fewer megabytes than it has megapixels? Surely each pixel of each colour channel contains one byte of info. In this case the pixel size is about 4.5% bigger than the file size. If (for example) I have a greyscale image of 1600 x 2400, PS says 3.67M. Calculator says 3.84, again about 4.6% bigger. What I seem to remember is something about there not actually being 1000 bytes to a killer-byte. Or was it bits to a byte? I know that this is academic, but I was trying to explain something to someone and my brain has got hung on this one... my cursor has stopped flashing. Giles Stokoe photographer/photojournalist. See some images at http://www.stokoe.co.uk =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
