IT8 calibration quirk- why?

[ian]

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.

[LSI_Noack]

Dear Ian

as the IT8 calibration in SilverFast is influenced by the gamma level set, this would be a place to start the 'quest': Is the gamma the same for your ICM settings and in all three apps?

Furthermore, the IT8 calibration feature in SilverFast is not influenced by any settings, it uses standard settings for maximum compliance.
It may well be that you need to reset other scanning apps to factory settings and deactivate any automatic adjustments made there.

Best regards
Sonny Noack
- Manager Technical Support, LaserSoft Imaging AG -

[ian]

Yes, the gamma settings are the same in all the programs and in the Mac's system profile (under calibration). I've also made sure that I'm using the same colour space and rendering intent everyehere. I have now also re-downloaded the IT8 data for my test target from Kodak. Nothing has changed.

[mntbighker]

Yes, the gamma settings are the same in all the programs and in the Mac's system profile (under calibration). I've also made sure that I'm using the same colour space and rendering intent everyehere. I have now also re-downloaded the IT8 data for my test target from Kodak. Nothing has changed.

I just bought an i900, did anyone ever find the answer?

[Anton Marc]

I want to know whether any settings in the Options window under any of the buttons (General, Auto, CMS, or Special) will have an effect on IT8 Calibration and the resulting ICC Profile for my scanner?
Sonny Noack's comment in this thread is very confusing as he says "IT8 calibration in SilverFast is influenced by the gamma level set..." and then says "Furthermore, the IT8 calibration feature in SilverFast is not influenced by any settings...