Sekonic SR-6500 HYBRID Operating Manual page 106

Dropout wavelengths and print colors
Peak sensitivity wavelengths for
the image reading sensor
630(nm)
520(nm)
470(nm)
PCS (printed contrast signal)
Refers to the reflectance ratio (contrast) of printed marks, symbols, and letters
as opposed to reflectance of non-printing areas. The calculation formula is as
follows.
PCS =
When reflectance of non-printing areas is 70%, and reflectance of printed marks,
symbols, and letters is 10%, the PCS will be 0.857.
Direct under type
If paper has pre-printed timing marks, the scanning area (reading area) of targeted
mark frames will be determined by such timing marks.
Direct under type is a method of reading a zone that is the same as the timing
mark width.
Other methods include timing control type, mark to mark type, and FACOM type.
Timing mark
Colors
(print colors)
Shades of red
Shades of green Pale blue
Shades of blue
White reflectance - black reflectance
White reflectance
Mark frame
OMR glossary
Typical print colors
Rose
Pink
Red
Orange
Yellow
Yellow
Cobalt
Light cobalt
Sky blue
Light blue
Reading zone
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