This section is from the book "A Treatise On Architecture And Building Construction Vol4: Plumbing And Gas-Fitting, Heating And Ventilation, Painting And Decorating, Estimating And Calculating Quantities", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
43. The mixing of any two of the primary colors produces a secondary color, and as there are but three primaries, there can be but three secondaries. The three primary colors, red, yellow, and blue, when mixed in pairs, form the three secondaries, as follows:
Red, combined with yellow, forms orange; while red, combined with blue, produces violet or purple. Yellow, combined with blue, gives us a green, while its other combinations with red, as well as the combinations of blue with red and yellow, are above described.
Orange, green, and violet or purple are, then, the secondary colors prepared by mixing as above, and may, in some cases, be obtained direct from the pigment itself. The combination of one secondary with any other secondary » color, will produce a tertiary color.