White target drift?
2009-12-19 by Bob
So a few days ago I created a target for the first time in a while; I'm using the latest SpyderPrint 4.1.1 with an older model 1005; it has a serial number under 1500. To my surprise, an evaluation print showed neutral colors coming out rather brown. After repeated remeasurings, I started fooling around with it and came to the conclusion that at a minimum the white calibration was faulty; if I use a piece of white paper to calibrate rather than the original target, the resulting print is much more neutral. I'm not sure, however, if the problem lies in my spectrocolorimiter, the calibration target, or elsewhere, and would like to know what my options are beyond buying a whole new kit. A bit more detail: I'm trying to profile some Epson Premium RC Semi-Gloss for use on a Canon ipf6100 (there was a great deal on this paper at B&H). If I use the white target to calibrate, the Epson Semigloss paper has a LAB around (97,1,-90) -- *really* blue; this paper isn't exactly neutral but there is no way that it is that blue. Some Canon Photo Paper Plus II, which is visibly whiter, measures around (97,3,-5). Some Inkpress Matte 80 measures around (98,3,-98). If I calibrate using the Canon paper as the white target, the Epson semigloss measures around (91,-2,-1), while the Inkpress Matte measures around (93,0,0). I'm really not sure what to do here; this does seems surprising given how far apart these papers are when I use the official white target to calibrate. And yes, this is repeatable; the numbers change a little bit but within a few percent the character of the result is the same, going back and forth between the two calibration targets. Thanks for any suggestions.