Hello , I am using the INTERPOLATE command to compress a stack of 2D (thresheld to binary values) images into a Vol files. I have noticed a fair amount data loss and have been searching for the source of the INTERPOLATE command within the IDL library with no success. I had hoped to rewrite the current ( nearest 8 pixel , weighted, meaness and brightness) to one that incorperated a catch for the existence of any pixel value, so as not to lose that data. (somehow, still haven't figured it out exactly). Thanks Dave