Re: Untagged RGB to Lab conversion
Re: Untagged RGB to Lab conversion
- Subject: Re: Untagged RGB to Lab conversion
- From: Jon Meyer <email@hidden>
- Date: Tue, 18 Dec 2001 07:56:27 -0500
Hello David -
Long before ICC there was Lino/Hell/Crosfield. They had the "secret
sauce" to do great conversions in color.
The ICC paradigm just simplifies the cookbook for us more common
folks. As you recognize, raw camera RGB sees color slightly skewed
from what the human eye expects it. That is why PhaseOne and others
includes profiles with their cameras. They in effect are "teaching"
the camera how to see as the human eye expects the color to look.
Raw camera RGB is a product of the CCD hardware, other hardware
attenuators such as digital/analog converters and of bits of code
including Look Up Tables. Once the signal has run through all those
hoops, the camera manufacturer ends up with something which if
hopefully profilable to further fine tune the process. The choice of
camera target partially determines the accuracy achieved in defining
the gamut of the hardware/software combinations.
The bottom line is that none of the cameras out of the box achieve
the level of quality which the discerning photographer is looking
for. Those that include clean canned profiles approach the expected
level of quality. Most can be improved with custom profiles.
- Jon
how are RAW RGB values determined? Sensor R,G, and B filters as
primaries plus secret sauce? Is there any way to convert from RGB to
Lab without defining the RGB colorspace?
--
*******************************************************
Jon Meyer
GrafixGear
email@hidden
http://www.GrafixGear.com
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Ridgewood, NJ 07450
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(201) 447-1510 voice
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