Does anyone know a method, or where I can buy pure grey paint? Preferably aroun d 12-25% in reflectivity? When I mean pure grey, I am referring to equal amount s of RG&B vlues. Is such a product made off the shelf?
Does anyone know a method, or where I can buy pure grey paint? Preferably aroun d 12-25% in reflectivity? When I mean pure grey, I am referring to equal amount s of RG&B vlues. Is such a product made off the shelf?
Wow, 12% does seem rather dark. Since paint is made out of pigments, it operates on a CMYK mixing system. I am not sure if you can obtain an even set of RGB values.
If you're looking for collour neutral grey, then I'd suggest looking at a Munsell Colour chart and getting a grey which is closest to your needs.
www.creativepro.com has an interesting write-up on painting one's environment a light Munsell 8 grey which can be whipped up at the better paint suppliers. The page also mentioned others who have achieved grey using their own stated formulae. The light Munsell 8 grey is used for the walls and ceiling of the author's workroom that holds his graphic monitors.
Bill,
Find a supplier of Rosco motion picture materials. They make various paints and I seem to recall they do white, black and grey cyc. paint which is colour neutral.
Good luck,
Walter
Erik, I was very intereted in that paint, but could not find that article on the link you provided?
Erik,
Thank you for the link - look like interesting reading at morning tea today!
WG
Bill,
I located the article by typing 'paint munsell 8' in the search box. The article is entitled 'The darkroom makes A Comeback Part 2' and in the text is a link to Part 1.
Cheers,
WG
What's your intended use?
It's not really possible to recommend a color space or analysis method without knowing the project if it's technical; if it's NOT technical, then the "match a chip" is probably the best way to go.
John, I am using it for grey point calibration for scanning. I want a reference point of something in my image that has equal RGB values. I tried the "match a chip method"....but I am unsure if the outcome is equal amounts of RGB... how can I determine this? I felt there must be some ready made product that is already "certified" grey as one of the posters mentioned above...
Bill,
Sinar use the MacBeth Colour-Checker as their reference. It is 'printed' with pigments not dyes.
Walter
Anything resembling paint will most likely change over time because the pigments are somewhat fugitive but not equally so. Even reference charts used to white balance broadcast level television cameras need to be retired from time to time. There is a rather good greyscale chart from Smethurst in England that might serve your purpose, but if you regularly subject it to intense light, it may not last forever either.
In my experience, reflective/transmissive color measurement devices aren't standardized with grey paint. The last spectrophotometer I used had green and white ceramic reference plaques provided with the instrument.
For technical purposes, mid-tone references aren't as useful as you might think, because humans and machines don't see color space the same way. Your best bet is a Macbeth color reference card (also useful for tests of slide films).
The Macbeth chart would allow you to photograph it and compare the end product (a print?) to it. Otherwise I suggest you find out if your scanner manufacturer has a recommended color calibration scheme.
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