HCT User Guide
page 6
Copyright © 2001 HutchColor, LLC
User_Guide_43.docx 2/10/19
Requirements
•
The HCT must be in good condition, without fading, staining or damage.
•
Each HCT has it’s own unique reference file which matches the target serial number.
•
Most benefits will be seen in a ‘raw’ workflow where all image optimization is done afterwards
on the RGB image (see ‘Recommended Workflow’.)
•
As with any other target, when profiling digital cameras, extreme care must be taken to avoid
surface reflections or uneven lighting when capturing the target.
Dye fading and measurement accuracy
Due to the delicate nature of photographic dyes, even with careful storage and handling the HCT
may fade or change color over time, however recent testing
1
indicates they are highly stable.
Within limits, worn or faded HCTs may be restored in value by re-measuring. An HCT re-
measurement service is available through the HCT dealer network.
NOTE
: Customer-measured data may not agree with supplied reference data due to dye fading and/or
instrumentation differences. Although reference data are supplied to three or more decimal places, the
least significant digits are uncertain and may be safely ignored by the profiling software.
Manufacturing date vs. measuring date
Batch dates marked on each target indicate the date of exposure and development, not the
measuring date. Measurements are made as near as possible to the shipping date.
Anticipating the demise of various emulsion types, large batches of HCT targets were produced
some years ago and placed in archival storage. Small quantities are measured and packaged as
needed to ensure measurement data are as fresh as possible.
An HCT’s manufacturing date does has no impact on its quality, effectiveness or longevity.
1
To evaluate long-term stability, five HCT targets of various emulsion types were re-measured in 2011 and the new CIELAB
data compared to ten-year-old original measurements. The worst delta E of all patches on all five targets was 1.7 (probably
due to dust or positioning) and the average delta E on all five targets was less than 1.0. This kind of error is in the same range
as typical instrument variation and indicates the HCT emulsions are extremely stable.
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