Re: Untagged RGB to Lab conversion
Re: Untagged RGB to Lab conversion
- Subject: Re: Untagged RGB to Lab conversion
- From: David Remington <email@hidden>
- Date: Wed, 19 Dec 2001 07:42:41 -0500
The answer depends on a number of variables, including the type of
sensor, its filters,
the type of analog and digital electronics controlling the sensor,
the image processing,
etc. Perhaps if you would clarify this a bit more...?
Thanks Robin. You have partially answered my question in regards to
the Better Light camera. There is much discussion here regarding the
importance of selecting an editing space large enough to ensure no
capture data is clipped. I'm curious, and a bit concerned, about what
has happened before you even open the file. I've worked with and
evaluated many cameras at this point and find their raw, by raw I
mean gray balanced and camera processed (exposure and contrast
referenced to a gray scale), data more or less mismatched to standard
editing spaces. In general the image is oversaturated in any of the
large gamut spaces. This was most noticeable with a Jenoptik camera I
looked at. That data fit Colormatch most closely. So, to clarify,
does in camera processing include targeting a particular
(anticipated?) color space? How does this effect the integrity of the
capture? Is the data clipped and or de-saturated? There must be some
strategy for the selection of RGB values.
Is RGB data completely defined by the box you draw around it?
I do not understand what you mean here? Please clarify.
I guess this is a reiteration of RGB device dependence. Is it true
that without a color space (primaries, white point, gamma, or LUT)
RGB values are meaningless? I'm just wondering how to best evaluate
the accuaracy and integrity of a digital capture and have hit a snag.
I can't fairly judge the file in my standard editing space and I
can't convert to Lab. What is left?
--
David Remington
Photographer
Digital Imaging and Photography Group
DN-90
Widener Library
Cambridge, MA 02138
617-787-4032