RE: i1Pro weirdness & fix
RE: i1Pro weirdness & fix
- Subject: RE: i1Pro weirdness & fix
- From: Ethan Hansen <email@hidden>
- Date: Fri, 19 Feb 2016 07:57:50 -0800
- Organization: Dry Creek Photo
> From: Graeme Gill
> > It would be great, because Lino has no possibility to measure strips,
> > so it's not possible to "clean" the lamp with the native measurements.
>
> Yes - there's no public information about how to do something like that
> with the spectrolino.
A simple-stupid approach would be to manually click the measure button on the lino until you get bored. Do enough measurements in a row and you'll burn off the crud.
As an aside - we have seen signs of the behavior Graeme mentions where L* drifts with repeated manual measurements. In our case, it was on Spectrolinos used for quick, manual spot measurements comparing putatively identical colors on different pages of a printer profiling target set. When we did a routine cal check on these two linos, they had drifted significantly, particularly considering that neither one had made more than 75 or so measurements since the last calibration check.
We then made a measurement pass of a ~1500 patch target with both suspect linos, comparing the measurements against data from a known good unit. The first few couple rows showed the most variability, and then the measurements settled in to normal tolerances. In both cases, our assumption was that the alignment was off on the Spectroscan table. A second measurement pass showed normal behavior.
None of us were bright enough to think of Graeme's idea of correlating quartz-halogen lamp behavior to the L* drift we observed. It makes perfect sense in retrospect, explaining exactly the behavior we measured. Kudos to Graeme!
> > Also I think it can help to restore some i1Pro lamps because when the
> > lamp became too dark, the software failed to calibrate it, so it's not
> > possible to "clean" the lamp with the regular strip measurements.
> > What do you thing about it? Whether it can help to restore lamps?
>
> Maybe - although they may really be at the end of their life if they get
> to that point ?
I'd agree on the last point. When a unit regularly fails software calibration it is a sure sign that the lamp has passed the end of its useful life. If you manage to squeeze a few more chart measurements out of the unit by either attempting the calibration enough times to get a pass or using measurement software that allows you to bypass the calibration entirely, the lamp is almost certain to burn out soon.
Cheers,
Ethan
----------------
Ethan Hansen
Director
Dry Creek Photo
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