On 8/15/2011 11:59 AM, Corinna Vinschen wrote: > Are you talking about recent gimp versions?
I wasn't talking specifically about any GIMP version -- I was surmising based on what you guys described as GIMP's behavior. > In my gimp I have the > choice of four different interpolation algorithms, "None", This sounds like the dumb "pix every Nth pixel" algorithm. It probably devolves to > "Linear", ...this, when the downsampling factor is not an integer. ("linear" is implicitly "bi-linear" when you're dealing with a 2D image). > "Cubic", and "Sinc (Lanczos3)", whatever each of them means. I guess I > just don't want to know in such great detail... Sinc is the theoretically "correct" operation, but for obscure reasons can't *really* be implemented in real life, because a /true/ sinc function has infinite extent. So, they probably mean a "windowed sinc" function...which has other (mostly theoretical) problems (unless the "window" is not a simple "box" window, but is instead a hamming, hanning, or certain other "windows". But even then, you encounter certain OTHER arcane problems. In practice, I'm sure either cubic or sinc will be fine. Cubic is usually faster. In the end, what *looks good* is what matters here. -- Chuck