HCT User Guide
page 13
Copyright © 2001 HutchColor, LLC
User_Guide_43.docx 2/10/19
Extending highlight detail
If a profiling target has a higher D-min (darker white) than a typical original, the resulting profile may
fail to recognize very light details in over-exposed transparencies. To solve this, you can fool the
software into thinking the target has a lighter white by extending the highlight contrast of the target
scan. (Both highlight and shadow detail can be extended at the same time).
This method of highlight extension is ideal for capturing painted artwork or wash drawings, where
the white art board and certain white paints can be much brighter than the white of a target made
on photographic paper.
•
In Photoshop’s Levels control, reduce the top right number until the HCT white patch reads the
same maximum RGB value found when scanning artwork substrate. An increase of about ten
RGB units in the HCT’s white patch (produced by a Levels highlight entry of about 245) is
usually enough.
•
Make sure the Levels change does not drive RGB values in the HCT white patch past 254. If it
does, either reduce the amount of extension or change the scanner’s RGB setup to get a lower
RGB value in the HCT white patch, then scan the target again.
Extending highlight contrast in Levels
•
Note that if you scan both artwork and photographic prints you should make two profiles from
the reflective HCT, one for photographic prints, with no extension, and one for painted artwork,
with the extended highlight method.
CAUTION
: In most cases extended profiles will improve shadow detail, shadow colors and/or highlight
details compared to ‘normal’ profiles. However an extended profile is technically less accurate than a
‘normal’ profile, and the difference may be more apparent with larger originals.
Lightening 'dark' 35mm profiles
35mm scanner profiles often produce results that seem too dark, even when great care has been
taken in scanning and creating the profile. This is often seen as a failure of either the target or the
profiling software, but the explanation is usually much simpler.
Darkness caused by flare in the target scan
Optical flare in the target scan can make 35mm images seem darker than expected, because if flare
makes the darkest patch in the target produce lighter-than-normal RGB values, the profile will
