(without more context, I translated traité as printed, it could also be processed as, etc.)

flat color
Color that lacks contrast or tonal variation. Also called "flat tint."

Tint :
The colour resulting from a mixture of two or more colours, or a diversity of nuances of the same colour. A broken tint is a tint to which black or blue has been added. A flat tint is a tint occupying a certain surface and having the same nuance and same intensity throughout this surface. A half-tint is the intermediate tone between light and shadow.

FLAT COLOR Any color that is printed without being overlaid by another color. Flat colors are used instead of process colors on jobs involving a few plain colors. The colors are usually selected by Pantone color number. Two- and three-color advertising materials not involving photography are printed in flat colors. There is no overlaying of color dots or color trapping. The advantage of a flat color is its uniformity of color. Each color printed in a flat color requires its own ink and printing plate (or cylinder) on a press. See also PANTONE PROCESS COLOR SPOT COLOR TRAPPING

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Note added at 7 hrs (2007-07-19 05:13:46 GMT)
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writing error: (I left out "as" in the entry)

processed AS a flat tint/color