Re: instrument calibration
Re: instrument calibration
- Subject: Re: instrument calibration
- From: Roger Breton <email@hidden>
- Date: Sun, 30 Jun 2002 11:49:01 -0400
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I have a white Spectralon reference tile that is calibrated to NIST standards
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that I can
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measure spectrophotometers against. When your spectrophotometer gets too far
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from the
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standard, it should go back to the manufacturer for recalibration and
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recertification. I
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know that GretagMacbeth and X-Rite have services for recalibrating their
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instruments. You
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should check with SpectroStar to see if they also offer this service. If you
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really want
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to check the accuracy of the spectrophotometer, erbium oxide and holmium oxide
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standards
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can be used. They have much more precisely defined peaks and valleys in their
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reflectance
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spectra that can be used for determining wavelength accuracy of your
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instrument.
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>
Robin Myers
The problem with White reference standard, IMHO, is that it won't catch
wavelength scale errors. I used to own a Spectrocam for a while, until I
returned it for refund, and I remember checking its response on a similar
White calibration standard, one that came with a Datacolor Spectroflash
sphere instrument. Well, as long as I kept measuring white and neutral
colors, there was always very close agreement between the Spectrocam and the
Datacolor, and a 938 and a Spectrolino: very little difference indeed
because none of these measurement involved the wavelength scale.
But the moment I tried to measure saturated colors, like the RGBCMY patches
on a ColoChecker, all bets were off.
Regards,
Roger Breton
Laval, Canada
email@hidden
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