IT8 calibration quirk- why?
PostPosted: Thu Sep 15, 2005 11:03 pm
This is not a huge problem but I'm curious as to why it happens:
I have a Microtek i900 with the supplied IT8 calibration kit and I can calibrate sucessfully in both the Microtek driver and Silverfast using the same supplied Kodak Q60 test card. The odd bit is: even using the same test card and the same scanner, the "flat" response of the scanner is different in each driver. In Silverfast, although there are no perceived colour cast differences, the resultant scan is a bit washed out and lacking in saturation compared to the Microtek driver's version (nothing that a tweak can't fix) Then I tried loading the Microtek generated profile into Silverfast with the same result. It's as if Silverfast is doing something to the profiles. After calibration surely the black panel on the far right should be black or very nearly so (in the region of 0-10 RGB) and the white at the far left should be in the region of 245-255 RGB not 40 and 215 respectively? The Microtek driver's "flat" scan is as I would expect it and frankly produces better default scans. It's as if Silverfast is using the profile to remove colour casts but not to adjust contrast and saturation.
I have access to an Epson 3200 also with IT8 this time the silverfast version and "flat" scans from that share the same characteristics- predictably so, I know that by tweaking levels and saturation by so much each time produces "accurate" scans.
I've looked in the set-ups of each driver to remove any "auto corrections" or "auto clippings" and, yes both drivers and Photoshop are sharing the same colour settings including gamma.
Like I said, not a big problem but annoying.
I have a Microtek i900 with the supplied IT8 calibration kit and I can calibrate sucessfully in both the Microtek driver and Silverfast using the same supplied Kodak Q60 test card. The odd bit is: even using the same test card and the same scanner, the "flat" response of the scanner is different in each driver. In Silverfast, although there are no perceived colour cast differences, the resultant scan is a bit washed out and lacking in saturation compared to the Microtek driver's version (nothing that a tweak can't fix) Then I tried loading the Microtek generated profile into Silverfast with the same result. It's as if Silverfast is doing something to the profiles. After calibration surely the black panel on the far right should be black or very nearly so (in the region of 0-10 RGB) and the white at the far left should be in the region of 245-255 RGB not 40 and 215 respectively? The Microtek driver's "flat" scan is as I would expect it and frankly produces better default scans. It's as if Silverfast is using the profile to remove colour casts but not to adjust contrast and saturation.
I have access to an Epson 3200 also with IT8 this time the silverfast version and "flat" scans from that share the same characteristics- predictably so, I know that by tweaking levels and saturation by so much each time produces "accurate" scans.
I've looked in the set-ups of each driver to remove any "auto corrections" or "auto clippings" and, yes both drivers and Photoshop are sharing the same colour settings including gamma.
Like I said, not a big problem but annoying.