[argyllcms] Re: White Point

  • From: Elle Stone <ellestone@xxxxxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 14 Oct 2015 13:17:36 -0400

On 10/14/2015 12:52 PM, Hening Bettermann wrote:


On 27 Sep 2015, at 17:00h, Hening Bettermann <hein@xxxxxxxxxxxxx> wrote:

Now I want to improve my general purpose camera profile even further. I have
bought a roll of white thread sealing tape and a meter of black velvet. When I
see your (Elle Stones) setup for shooting the target
http://ninedegreesbelow.com/photography/camera-profile-make-target-shot.html
I get 2 questions:
1- How do I talk scanin into recognising the added black and white patches as
part of the pattern? (the ColorChecker Passport in my case).
2- The light I will be using is 2 Solux lamps at a 45° angle. The vertical
distance from the lamps to the target is 55 cm (22 inches). Would it not be
preferable to make the black trap a good deal deeper than approximately 10 cm
(4 inches) ? Ideally to a place behind the lamps (towards the camera)? And
could/should they be placed outside the target surface that I try to illuminate
as even as possible? I mean they should ideally not be illuminated at all - ?
Thank you for your advice! - Hening.


Well, the expert on black traps and lighting is Ben Goren. My article has links to some of his very helpful posts on the topic.

I don't think you really want to get scanin to recognize the black and white patches, but hopefully someone else will chime in if I'm wrong. Rather you use those patches to help set the raw color interpolated target chart's black and white points. And then you add "synthetic" or perfect black and white extra lines to the ti3 file:

http://ninedegreesbelow.com/photography/well-behaved-camera-profile.html#add-D50-white-black-color-patches

Best,
Elle

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