[argyllcms] Re: Generated camera profile too bright
- From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 04 Apr 2012 01:07:17 +0400
Tue, 03 Apr 2012 21:43:16 +0200 "Andreas F.X. Siegert" wrote:
>
> > Or you could apply about a full stop's worth of positive exposure
> > compensation during raw processing of your target shot and reprofile.
> > Or reshoot the target so it doesn't need so much positive exposure
> > compensation.
>
> There is no way to generate an image that will be bright enough after
> the switch to linear. The drop is just too radical.
>
May be there is the problem with RAW -> linear TIFF conversion as Graeme have
mentioned?
You can do simple test: just shot a bulb or bright white object in daylight
with defocusing and with overexposure for 3-4 stops. Then convert RAW into
linear TIFF with Your workflow. Check the resulting TIFF. The saturated areas
definitely should have 100% level in all three channel. If they have much less
level, there is a problem in the RAW converter with camera sensor saturation
levels. RAW channel values at fully saturated sensor area should become above
100% level in resulting TIFF. The saturation point shouldn't be within 0..100%
of linear TIFF scale. It should be slightly higher than 100%. Otherwise You'll
get huge color casts on saturated areas of images because of linearity loss in
"linear TIFF" data.
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