Chris Nellist wrote in message ...
Hi,
I would like to get some pots of ordinary emulsion paint
in the primary colours, i.e. cyan, magenta, and
yellow, as used by printers and as easily specifiable in RGB
for computer monitors.
The thing is, I need the colours to a high degree of
accuracy.
I understand that conversion between the Dulux/ICI codes
(or the NCS ones from which they are scrambled) and RGB/CMY
codes is not publicly available, so what I will do is get
a printer to print out primary C, M, and Y and then take
them along to somewhere like B&Q to be scanned with a
colour meter. However, I suspect that there may be a big
gap between the required colours and the best available
matches, since Dulux/ICI probably don't want to encourage
people to mix paint.
Any advice would be welcome. Simple question really - how
to get pots of primary-colour emulsion paint! 
Many thanks.
Cheers,
Chris
Chris,
offset inks are transparent and normally used on white paper.
Samples are in Pantone swatch books, either Pantone Solid or Pantone
Process. No need to print samples by a printer.
The Lab values for any Pantone Solid or Process ink can be found by
Photoshop or by measuring directly in a swatch book by an instrument.
The Lab values are not shown in the swatch books.
European inks are not exactly the same as US inks.
Reference viewing light is D50.
No problem to find the few Lab numbers, but the model has to be
defined (Pantone Solid, Pantone EuroScale Coated, for example).
Paints (varnishes) are opaque, not defined by Lab and viewing light
may be D65 (here I´m not sure about).
I didn´t find any cross-reference, but I would recommend to have a
look at the RAL system (Google: RAL Colors): e.g.
http://www.inver.it/liquid/ral.html
Some thousands of RAL mixtures are already defined and available
in swatch books. Perhaps it is sufficient to choose the nearest RAL
color by swatch book comparison.
Just for fun I´ve tried to find a company which mixes paints as
specified by Lab - no success so far.
Best regards --Gernot Hoffmann