by mivanitsky on Sat Sep 12, 2009 12:13 pm
Actually, this problem is more complex than you think.
To accurately reproduce the Agtron tiles, you would need to read the tiles with a spectrophotometer. You could then convert the color values to Pantone or L*ab equivalents. The former could be directly accomplished by getting the appropriate Pantone chips from a printing-supply company, but the latter is more practical. The L*ab values can be input directly into Photoshop, and a document with all the tiles can be created which can then be calibrated to an appropriate color space, and printed on any printer which has been accurately color-calibrated, including the ones at Costco.
It is also possible to download accurate color profiles for the specific Costco printer to which you plan to print, and convert the document to that profile in Photoshop, and then (only then) ask Costco to print without color management.
If you color calibrate your monitor, including luminosity, you could even use a computer by the roaster for these comparisons.
Use of either the real Agtron tiles or accurate reproductions assumes viewing under a stable illuminant of appropriate luminosity, CRI, and color temperature. Reproductions need to be printed using inksets which to not exhibit metamerism in the brown tones printed.
I have the necessary hardware and software to do this, but have never bothered, as I like to roast by eye, smell, sound, and monitoring of bean mass temperature curves. Actually creating such a file, and widely distributing it on this or any other internet forum, would surely be illegal, if the Agtron tiles are not public domain intellectual property.
-Mike