"Blue Turns Purple" Problem Revisited
"Blue Turns Purple" Problem Revisited
- Subject: "Blue Turns Purple" Problem Revisited
- From: "John Hollenberg" <email@hidden>
- Date: Wed, 04 Dec 2002 13:39:19 -0800
- Priority: Normal
I have calibrated my monitor with Eye-One Pro and Profilemaker 4,
and have a D50 custom printer profile for my Epson 2200. In trying
to track down why certain colors in soft-proof mode on the monitor
don't visually match the printed output, I did the following experiment:
1) Selected a particular blue which appeared particularly poor match to me
2) Created a L*a*b* document in Photoshop with color block 47,6,-44 (in
gamut of display and printer profile) and turned on soft proof for my printer
profile
3) Measured the block on my D65 profiled monitor and converted to D50
using calculator on Bruce Lindbloom's site - measured values 42.9, 7.54, -45.6
4) Printed the block with the D50 light source printer profiile and
measured the reflective values - 42.8, 7.1, -47.6
The delta E between printer and monitor is about 2 - a pretty good match.
However, when I view print of color block under D50 light source it doesn't match
the monitor. If I change the color block on the monitor a* value from 6 to 12 (add red to
make color block on monitor more purple) the match is visually very close.
I read about the "Blue Turns Purple" problem at www.brucelindbloom.com
but didn't think it applied because in this case measured values for monitor
and printer are very close. The problem seems to be a perceptual one.
Any help or explanations greatly appreciated.
--John
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