HutchColor HCT, Руководство пользователя

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HCT User Guide page 21
Copyright © 2001 HutchColor, LLC User_Guide_43.docx 2/10/19
Camera profiling
IMPORTANT : As with all camera targets, HCT profiles are optimized for the dyes or colorants in the
target itself. If the subject matter's colorants have different spectral reflectance curves, color accuracy
may suffer from some degree of "metamerism failure". There is no simple solution for this, except manual
color editing in Photoshop..
Due to the difference between target colorants and the colorants in real-world subject matter, no
profiling method can give perfect results all the time from all types of subject. A REALISTIC
expectation is that a good camera profile should reduce some of the gross errors usually
experienced, but some additional color correction will often be needed to match certain types of
subject, no matter how good the profile is.
Defining goals
There are two logical goals in profiling a digital camera. Choosing the most appropriate goal is the
key to creating a useful profile and workflow. The main difference between the following two
approaches lies in how the camera is adjusted during live capture, compared to the profiling capture
setup.
Copy work (scanner on a tripod)
The simple goal in copy work or fine-art reproduction is the most accurate reproduction possible
where the camera is in effect a ‘scanner on a tripod’. Copy-work may require a custom profile for
each individual set or setup, but a single profile may serve indefinitely so long as the same lighting,
camera and camera settings are used.
Film-type profiling
For editorial, sports, commercial or fashion photography, a more realistic goal is a profile that
delivers stable performance in spite of changes in lighting or exposure. This idea is similar to
standardizing on a single film type. ‘Film-type’ profiles may reproduce the subject less accurately
than ‘copy’ profiles, but should give a constant starting point that is closer to actual scene color than
possible with color film.
Camera profiling issues
Some of the problems that can limit camera profile quality include;
•
Target colorants (e.g. dyes) are different from those in the original
• Target white is darker than subject white
• Target black is lighter than subject black
•
Target colors are less saturated than subject colors
•
Uneven lighting over the target
• Flare in the camera’s optical system
• Reflections on the target
•
Inappropriate camera software curve
• Improper camera ‘white balance’ or ‘gray balance’