On 08/09/2010 04:16 PM, Charlie De wrote:
>> From Rupert:
>> (as far as I can tell, the current Decompose Lab functions are
>> broken, anyway).
> What makes you say that? And how severe is the problem?
> Right this minute I'm writing a script with LAB Decompose...
Well, 'different' might have been nicer than 'broken' -
The conversion doesn't account for gamma:
As a result, the L* channel is very light (check the histogram). I have
no clue how that influences a* and b*.
Also, it uses the conversion matrix for PAL/SECAM RGB. (Maybe PAL/SECAM
has gamma 1.0? Then the missing gamma correction would be correct.)
Anyway, unless your image is in PAL/SECAM RGB, the conversion in
Decompose is incorrect.
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