CHROMiX

Scanner white calibration

Recently, I’ve looked more closely at the white calibration strip on my Epson 10000XL scanner. What I’ve discovered is that the strip contains an optical brightner.

I would really appreciate Steve’s response to my post with a quick explanation of how scanner white calibration works, and why an OB enhanced calibration strip is used, and whether it’s feasible for one to substitute the factory calibration strip with one that contains no OB.

Thanks!

Sorry for my delay, again…

In theory the OB in the calibration strip will only be as much of an issue as the scanner’s lamp produces UV AND the system is set to compensate / expect it…

Calibration is really just a matter of returning a system back to a known condition. The known (and unpublished) condition in this case is set at the factory.

I would be leery of substituting a different strip for the original one unless you have a good feeling it will help (a known issue that is logically related to it) and you have a way of testing to see if it has in fact helped…

do you have a known issue you are dealing with?

Steve

Thanks Steve.

In a way, I do have a known issue I am dealing with. That is, in the fine art scanning work I do, I often have to capture subtle highlight details.

I figure that there is at least one if not a couple of factors that will affect the degree to which I can satisfactorily capture highlight details:

The first is the luminosity of the white patch in the scanner target used.

And, possibly, the highest white point to which the scanner is calibrated.

My initial question was partly based on my reasoning that a better scanner profile would be obtained if the scanner white and the target white are identical.

In my case, Lab = 98.0 -0.2 -2.0.

The Epson cal strip L = 96 (I’ve forgotten what the ab values are.)

Frankly, I haven’t really taken the time to definitively determine whether substituting the cal strip has improved my ability to capture highlight detail beyond merely using a suitable scanner target (in my case, the ColorChecker DC with modified center white patch).

On casual observation though, I think I’m experiencing slightly better results using my own cal strip.