Re: Camera Profile
Re: Camera Profile
- Subject: Re: Camera Profile
- From: Derek Cooper <email@hidden>
- Date: Mon, 21 May 2007 07:31:44 -0400
On 21-May-07, at 7:18 AM, Fleisher, Ken wrote:
1. Of the current crop of profiling packages for creating camera
profiles,
what are your experiences/recommendations for the best colorimetric
reproduction? (The task is exactly reproducing the original as best as
possible—-we can ignore issues of metamerism for the purpose of this
discussion.)
In my 4 years of shooting with high end digital backs (I'm assuming
you're talking about digi backs and not DSLR given where you work),
the best approach is to ignore camera profiling. In the last testing
we did, GMB ProfileMaker Pro 5.0.x is the best digi back profiler.
However, as good as it is, it merely gives you a new starting point
from which to adjust the curves.
The best approach - shoot in a "reproduction mode" if your digi back
software supports it. I use Flexcolor from Hasselblad to run my
digital backs, and they introduced this mode over a year ago. It
looks very dull on-screen, but is tone-to-tone incredibly accurate.
Include known reference targets. Here's a snip from a similar
response I wrote a few days ago for another group:
-- snip --
Andrew Darlow's new book "301 Inkjet Tips..." that is due out next
month has 4 or 5 chapters written by me in it that talks about repro
shooting, and the techniques used to generate amazingly accurate
results.
Repro mode turns off the curve Hassey adds to FC for all images, so
the shot looks very dull and certainly far from vibrant. If you read
the PDF on the repro mode that I posted to the Yahoo group about a
year ago, you'll get a quick overview of how to use it.
In my setup, I get my light balanced (I can dial in around 128 - 130
on the GMB ColorChecker Chart neutral grey patch) after neutralizing.
I find that is key - get good mid-tone light. Then, drop into repro
mode by checking off the box in the dialog (can't remember which one
- and I don't have FC open at the moment - sorry!) Everything goes
dull. Don't neutralize, or change your lighting.
Now shoot. But this is where things might not work for you - you need
to include three known colour references in each shot so you can
adjust later in PS. For me, black velvet, the grey 5 on the GMB
ColorChecker chart, and I use a BabelColour white target (http://
www.babelcolor.com/main_level/White_Target.htm). You don't have to
wear it on your wrist! :)
You shoot your shot using the Hassey RGB input space, then save as
TIFF in Adobe RGB from FC. Open the image in PS, bring up your
curves, and you need to edit the black, white and mid point for each
of the three colours (R, G, and B) to match the readings you get off
the known targets. I use an Eye-One Pro Spectro and GMB's Color
Picker to get my known colour reference data assuming D50 illuminant
in the Adobe RGB space (which are both important, cause as you know,
the values will change in different light and for a different space).
Drag you black point in to match, your white point in to match your
readings, and then add a point for mid, and usually drag it up
slightly to get it to match you own known grey patch.
That's it!
-- end --
Let me know if you have any questions Ken.
Derek Cooper Photography
www.derekcooper.com
www.reproducingart.ca
V 613-767-9106
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