How to get primary (C,M,Y) emulsion paint, e.g. Dulux?

[Frank Erskine]

On Tue, 2 Nov 2004 08:56:40 -0000, "stuart noble"

We regularly buy black emulsion for theatrical "sets".

[Roger Breton]

Alan, could you extend the generalization above to include any two 'complentary" primaries to inks? For instance, a PANTONE 185 which is red in appearance and a PANTONE 347 which is green in appearance. Could you say that mixing these two inks will yield a brown?

Roger Breton

[Roger Breton]

Alan, how do you operationalize 'covering capacity' or opacity? Do I average out the spectral reflectance from 400 to 700nm out of my spectrophotometer?

Roger Breton

[Jo Taylor]

Hello. Not without knowing exactly to which inks you are referring. I checked all the Pantone range and only found matching numbers red and green in 'Pantone Uncoated'. 185 red is close to pure - just a hint of yellow - and the 347 green has a strong grey content. But, if such colours existed in opaque paint, it is most likely they will produce a brown. A lot depends on the nature of the paint or ink. For example, in artists acrylic most manufacturers produce different ranges - school, student and artist qualities being typical. The 'school' quality is cheap and the 'artist' quality anything up to four times as expensive with quality of pigment and amount of body (chalk or carbon) being the important factors. An artist quality primary blue mixed with a similar quality yellow will give a very good, clean green. The same colours in school quality will be much greyer (or 'muddy') when mixed. If, in referring to ink, you mean drawing inks and not standard printers' process colours then, depending upon the quality of the inks, such a red and green would produce brown. Opaque silk screen ink works just like paint in that it is mixed before application and does not rely on transparent overlay as in the process CMYK system.

I think a lot of the confusion is eliminated once it is understood that three distinct colour systems exist - RBY (paint, opaque), RGB (light, transparent) and CMYK (printers process inks, also transparent). Each has its own set of primaries, secondaries and complementaries and mixes within any system create different results. A standard six colour RBY colour wheel will always show green opposite red and the two, when mixed, will produce a brown with a red bias - 100% red + 50% blue + 50% yellow - just as a blue/orange mix will produce a brown with a blue bias.

I would be happy to discuss this further off list if you want to contact me.