theSuede Offline Upload & Sell: Off
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I'd like to add three things about what has been written the last few pages (I didn't read to diligently, I just skimmed it...).
1) Whitebalance in raw converters are NEVER, EVER done in Lab. That would be very performance degrading, and actually a very inaccurate way to correct colour.
You have to do WB in the first raw stage, before you even put the raw values through any interpolation. Done at this stage, you get as close to zero conversion artefacting as the value accuracy will allow.
2) Most of the resampling colour faults you see in pictures with high spatial frequencies stem from the fact that you are trying to apply linear theory math to RGB values that are both S-curve- and gamma-treated. You can get around some of those issues by actually doing the resampling in Lab, but you can never get around the fact that you're trying to interpolate between values that are already messed up (have the wrong scene-related contrast).
Working on curve- and gamma-treated values will always have a large impact on the relative detail contrast. The contrast that remains after a rescale depends on the average value of the surrounds - midrange contrasts get a boost, and bright areas are often undersharpened, dark areas oversharpened.
Unfortunately, there's no (practical) way to do things "in the right order" until we have raw-converters that actually give you that option. Until then, we have to make do with what's "visually pleasing", and this is somewhat of an arcane art - it isn't quantifiable.
3) As in most other things, the large software manufacturers are terrified of things that "can go wrong". So almost every editing action that's available is tuned for safety (non-aliasing, non-artefacting) and for performance - performance as in "time spent" or "processing cycles spent", not in "accuracy or pictorial performance". The same goes for resampling algorithms. BiCubic is chosen because of the almost total resistance to aliasing in natural scenes (not testcharts), even though there are other easy ways to do it with much higher accuracy and not much more processing power involved.
Lanczos in the 3- and 5-lobe versions are very good, almost as good as a complete Sinc reconstruction (which would be the same as the FFT toothwalker showed).
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