IT8 Calibration Error

[RogerMillerPhoto]

During IT8 calibration of a Polaroid SprintScan 120 using an IT8 transparency, I get the message, "Error: Gray scale sampling unacceptable. Please cancel and correct the current frame position."

But there's nothing wrong with the frame position. I'm wondering if there's something wrong with the IT8 reference file (TK199910C2) that I loaded from the SilverFast CD. I put it in the the IT8 Reference Files folder and located it properly before the calibration scan started, but SilverFast can't seem to match the calibration file to the transparency.

Does anyone have an idea as to what the problem might be? I'm going to ask SilverFast via e-mail also, but they haven't been answering their mail lately, so I don't expect any help from them.

[ilyons]

This error occurs for a number of reasons:

1. The target scan MUST be in the horizontal (Landscape) format.

2. The crop frame MUST be set so that the max white and black patches are EXCLUDED.

[Tomaz Klinc]

Hi Ian, glad to see you here

I have the same problem as Roger: IT8 calibration of latest SF v5.2.1r08(NikonM) quits while scanning the gray scale of Kodak's Q60 target even though the marquee is properly positioned. In any case, you would agree, the program should not report a fatal error and shut down after a repeated attempt to calibrate. By email I asked LSI about this, was promissed a reply, but they did not deliver on the promise.

In another thread on this Forum, a Mr. Martin from LSI's Florida office suggested to shrink the marquee a bit, so that it's border lies slightly within the gray scale and other color patches. Didn't try this yet, but it was unnecessary with previous versions of SF.

This brings me back to English editon of the SF Manual, which, as you know, I find a pain in the neck to read. It's explanation of IT8 calibration is so mangled, that the above problem comes as no surprise. This Manual is in a dire need of a thorough editorial job.


<font size=-1>[ This Message was edited by: Tomaz Klinc on 2001-08-08 12:13 ]</font>

[ilyons]

Hi Tomaz,

The problem must be PC specific since I cannot repliicate it on the Mac. I have even went as far as setting for mult sample and ICE on - nothing cause the software to fail the calibration or crash. These two features should have no influence on the calibration, but it was worth a check to see if somehow they were.

Ian

[RogerMillerPhoto]

I talked to Martin (at SilverFast) on the telephone. He asked me to send him a screen grab of the calibration screen (right after I hit 'Pre Scan.' I just now did that. It sounds like a software bug as I'm using the right IT8 reference file (TK199910C2) and it matches the C-ROES transparency. I'm using a PC. Also, I used a scan type of '48 Bit HDR Color' rather than '36->24 Bit Color,' but that shouldn't make any difference. Other than that, I did everything as described in Ian Lyons IT8 calibration tutorial. I guess now we wait for Martin to figure out what's causing the problem.

<font size=-1>[ This Message was edited by: RogerMillerPhoto on 2001-08-08 22:52 ]</font>

[RogerMillerPhoto]

I upgraded to version 5.5 of Ai and now I can do an IT8 calibration of both my Polaroid SprintScan 120 and SprintScan 4000 scanners. I used the same technique as I'd tried with the older version. So, I'm inclined to think that there's a bug somewhere. That's inspite of the SilverFast folks not being able to duplicate the problem. I won't guarantee that an upgrade ($45US) will solve the problem for everyone, but it seemed to for me.

[RogerMillerPhoto]

I've discovered two problems with the SilverFast furnished C-ROS IT8 35mm slides that were delivered with each of my two scanners. Both slides were dirty when I received them. The dirt was stuck to the slide or embeded in it and couldn't be brushed off. (SilverFast needs to take better care of those slides!) If a speck of dirt happens to be in a location where the calibration software takes a reading, it's possible that the software would reject the calibration attempt due to the reading being too far off from what was expected. I really doubt that that was my original problem, though it makes me wonder if a bad calibration might occur due to dust and dirt on the slide. The other problem I found was that the film is not held tightly in the slide mount and can move. In fact, it can get so far askew that the calibration guide lines are no where near parallel to the edges of the slide target. I know that this was not the cause of my original problem as it's very obvious. An askew slide target would certainly cause problems with an IT8 calibration, and if you notice the problem, you can probably jiggle the film back into the correct position by tapping the edge of the slide mount on a hard surface.

[rteye]

Roger Miller wrote -
During IT8 calibration of a Polaroid SprintScan 120 using an IT8 transparency,I get the message, "Error: Gray scale sampling unacceptable. Please cancel and correct the current frame position."

If the frame is set slightly off the error message will result. Adjust the frame so it is very slightly inside the indicated boundary and try again. Slight adjustment may be needed.

Barry

[RogerMillerPhoto]

Thanks, Barry, but I was doing that. It didn't help, but for some reason the problem went away when I upgraded to 5.5 . I've suggested to Lasersoft, and they think it's a good idea, that they add a feature to their software so it will display a red dot where the readings are being made on the IT8 slide. If any of the dots aren't in the middle of each of the little squares, then the users would know that "crop box" border would have to be adjusted and another attempt made. That would help with troubleshooting a problem like this. And a screen grab sent to Lasersoft by a user could prove to them that any problems were caused by a software bug and not a user adjustment problem, if indeed it was a software problem.