[argyllcms] Re: DIY reflective spectro
- From: "Alastair M. Robinson" <blackfive@xxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 09 Mar 2006 18:30:50 +0000
Hi,
Stephan Bourgeois wrote:
Hmm I'm afraid you're dreaming.
Hehe - thought I might be! :)
To begin with the weakest point in
flatbed scanners: the cold cathode lamp. Very spiky spectrum, you're not
going to go very far. This is why I got better results using a digital
camera as a poor man's colorimeter than a flatbed scanner.
Indeed. Nonetheless, if the light coming from the patch being measured
is split such that its spectrum covers even a quarter of an inch of the
CCD you're still getting *far* more information about the patch than a
simple RGB reading.
Even replacing the lamp wouldn't be totally impossible, bearing in mind
that we don't need to cover the full width of the scanner - just a small
patch.
Even if you were able to adapt the optical path and add a diffraction
grating or a prism, you would need some relatively accurate mechanics to
be able to *replicate* the angle of the prism/grating.
Really? If the position of the optics is fixed in relation to the CCD,
why is this a problem?
I can see that the CCFL's spectrum combined with the RGB filters that
(presumably) would be difficult to remove from the CCD would mean this
idea wouldn't give us accurate spectral readings, but I'm wondering if
it would be possible to calibrate the readings well enough to get
reasonably accurate XYZ measurements?
If this method could even come close to the ColorMouse's accuracy it
would be worthwhile simply because of the strip-reading potential.
Also, scanners vary a *great* deal - my Dad's just bought an Epson RX620
all-in-one machine, and the scanner's *fantastic* - I've generated two
profiles using it that come pretty close to those made with the ColorMouse.
All the best,
--
Alastair M. Robinson
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