Re: Characterizing semi-Translucent materiel
Re: Characterizing semi-Translucent materiel
- Subject: Re: Characterizing semi-Translucent materiel
- From: email@hidden
- Date: Mon, 27 Nov 2000 07:59:02 EST
In a message dated 11/26/00 11:01:48 PM, email@hidden writes:
>
Few people on the list ever speak of taking measurements off printed
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polyethelene (such as in bread bags) in developping ICC output profiles.
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Breadbags are not a common substrate among many of us, but backlit film and
related translucent sheets are... so there should be some kind of knowledge
base.
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There are methodology issues involved with reading such a characterization
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target that simply don't exist in reflective reading on litho stock. In
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particular, I am debating whether I should make those measurements with
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having placed some piece of white cardboard underneath the target (therefore
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artificially boosting their lightness range) or simply leave on the dark
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black metallic materiel of the Spectroscan the table (and this way more
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"closely" adhering to the standard measurement methodology)?
The first question is whether you should be profiling this as a reflective
material at all; or as a transmissive one. But I will assume you are printing
a white background on the imaged areas of your bags, that your bread will not
glow, and that the appropriate way to profile it is as a reflective media.
Then we get to the backing color issue: I would claim you should use a white
backing for any real-world profiling, and definately for translucent
materials. Then your software should be able to adjust your white point
effectively, and build a convincing profile. Examine an image converted to
this profile's space in Photoshop and see if the midtones are at an
appropriate tonal range; if not then you might want to reprofile with the
black backing for comparison. If they split what you feel is the right tonal
range, then be sacreligious, and profile on a neutral gray background! Once
you can get a reasonable result out of Photoshop, you can move on to test
runs of bags... I always enjoyed teeshirts with test targets on them, but I
must admit I never thought of a bread bag with a target printed on it...
C. David Tobie
Design Cooperative
email@hidden