Re: ICC DCam part 1
Re: ICC DCam part 1
- Subject: Re: ICC DCam part 1
- From: Michael Schnelle <email@hidden>
- Date: Thu, 03 May 2001 16:04:28 +0200
- Organization: Winkler Studios GmbH
Bjarne Sxrensen schrieb:
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Hi list
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Even if it should be so easy - I still hav4nt produced a desent profile!
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...someone help me please !
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How do I make the optimal capture - lighting?...what should my
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ColorChecker measure?..do I make the capture with the ICC-prefs set
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to none (Leaf DCBII) ??....
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The profiles so far change a lot under different lighting and exposure
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and when the profile 4s been generated in Photoshop the squares is
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very vissible - and the documentation says the less vissible the better !!
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I4m sorry - but what am I doing wrong .......
Hi Bjarne !
since three years I work with Eyelike DCS and Gretag ProfileMaker for
Colormanagement. But just three months ago I found the best way to profile my
camera. My way will sound pretty complikate and it really is hazardous ! But
after 1/2 day concentrated work You will easily be able to profile pictures
even with UV containing signal colors, never 100% but pretty near to the
original.
What You need is an IT8-scanner testchart with freshly measured
reference-data, the Gretag ColorChecker and a Kodak Greyscale You normally
use in analog reproduktion-photography.
At first You have to make accurate calibration of Your camerasystem by
shading-calibration on white and color-calibration on the ColorChecker as
Your camera-handbook tells You.
My best experience is to set the white level on the colorchecker to RGB 250
and black level to RGB 40.
Save your calibrations and create a special projekt for the type of light
You just use.
Take a preview of the IT8 scanner testchart together with the Kodak
greyscale. You will see that the white field of the Kodak GS is similar and
the white field of the IT8-TC is darker ( about RGB 230 ) than the white of
the ColorChecker . The black fields of both charts are much deeper than the
one of the ColorChecker( about RGB 5-10).
Change the exposure until You get the brightest channel on the white field of
the IT8-TC to 250 and set the white level on it and the black level where it
is. Take Your pictuer of the IT8 Testchart. It will be the measuring-data for
making Your profile for this setting.
Then again change the exposure to get the brightest channel on 250 on the
white field of the Kodak GS. For example You will read R 250/ G 247/ B 232
for white and R 16/ G 12/ B 1 for black. These are the calibration-data you
have to set in the balance window for white- and black-level. Make a new
preview with these settings and finally set white and black of the Kodak GS
to these data, save Your projekt and protect it !
Make each calibration for every type of light You normally use f.e.
flashlight, tungsten, daylight, fluorescent and save it as a kind of preset
as own projects.
Your daily work with Your camera system will be easy in this way: Build up
Your Set, make the light and then make yout preview with the Kodak GS in Your
set reflecting ( but never mirroring ) the main light. The exposure has to be
at 250 at the highest channel on the white field, set the white balance on
it. At this point it doesn4t matter if You have a little bit different light
to your calibrating light by using other reflectors. This mistake will be
eliminated by setting the white level. Then check Your exposure that any
field or color which has to be reproduced accuracy is not brighter than RGB
250 (except flashing highlights). Make Your picture and profile it from Your
new camera profile to LAB !
On this way I can reproduce most of the colors when making color critical
photography.
Will be continued in a second mail because it is too big for the list !
Winkler Studios GmbH
Michael Schnelle
email@hidden
[demime 0.97c removed an attachment of type text/x-vcard which had a name of schnelle.vcf]
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