Message
Re: [colorvision_group] PFPro 2.0 - Printing Targets - GO?
2007-01-11 by CDTobie@aol.com
In a message dated 1/11/07 10:43:35 AM, doug@... writes:
I have the GO setting on the Epson R1800 driver set to AUTO - I printed
the targets from PrintFix Pro 2.0 software.
Any thoughts out there?
Well, my main thought is that way too much consideration has been given to GLOP and its effects on profile building already. GLOP is mainly to fix an optical effect (I'm tempted to say optical illusion ) in which inked and uninked sections of the image, at close proximity, under extremely low light angle, show an unpleasant difference in surface reflectivity.
Patchreading devices work at a very precise 0/45 configuration where all the light is supplied at 45 degrees to the surface, and all measurements occur at zero degrees (perpendicular) to the surface (or in rare cases, the reverse). So gloss differential won't even be perceived by a spectro, and the angle is too tight. The white patch will, theoretically, read as a slightly different white when GLOPped or not GLOPped, but if you put an image with GLOP on the main image, but not the border, in a light box where the lightsource is 45 degrees from the image plane, and your eye is perpendicular to the image plane, and attempt to distingush where the edge of the GLOP zone is, and what difference there is in the color of white in the two sections... well, I don't think you'll see much that would concern you.
Other details of the profile calculation process minimize the difference even further. So overall, my level of concern about whether GLOP is or is not used in the profiling process is pretty low. Whether its used in a given print is a matter of how the print will be presented and displayed; if low level light and low level viewing angles may occur, then GLOP is a real benefit. But in a step-back matting system, under glass, on a wall with proper 0/45 lighting viewing angles (as in a gallery), its as moot for viewing as it is for profiling.
C. David Tobie
Product Technology Manager
ColorVision Business Unit
Datacolor Inc.
CDTobie@...
www.colorvision.com