Re: differences between colorimeter & spectrophotometer
Re: differences between colorimeter & spectrophotometer
- Subject: Re: differences between colorimeter & spectrophotometer
- From: Phil Green <email@hidden>
- Date: Fri, 05 Oct 2001 16:09:51 +0100
- Organization: LCP
Roger Breton wrote:
>
Compared to a spectrophotmeter in reflective mode, can a colorimeter in
>
emissive mode report 'absolute XYZ colorimetry' i.e. relative to the perfect
>
reflective diffuser (does reflective diffusion apply here)?
The same principle applies, although it is called a perfect transmitting
diffuser.
>
Finally, what are colorimeters calibrated to?
For measurement of emissive devices, they can be calibrated to a lamp
with known emission certified by a national standards laboratory. This
is usually done by the manufacturer. For measurement of reflective
samples, they can be calibrated to opaque standards (e.g. Ceram or BCRA
tiles) again certified by a national standards lab.
>
One last one, are there "standards" like GCA T-Ref or Lab-Ref that could
>
help validate the measurements of a colorimeter?
There are (emissive) standard sources, as described above.
--
Phil Green
Colour Imaging Group
School of Printing and Publishing
LCP
Elephant and Castle, London SE1 6SB
Tel: +44 020 7514 6759 Fax: +44 020 7514 6772
http://www.digitalcolour.org/