[weinzierl]

> It is also true to say "When you were told in primary school that the primary colours for your paints were red, green, and blue, this was untrue"

The reason that red, green and blue are sometimes stated as primary colors in the context of mixing ink layers is that red and green and blue are rather vague terms. What is meant by red in this context would more exactly be called magenta and green is used to designate cyan. Wikipedia puts it this way[1]:

> Before the color names cyan and magenta were in common use, these primaries were often known as blue and red, respectively, and their exact color has changed over time with access to new pigments and technologies.

Also I think education about primary colors is just a mess and the same Wikipedia article[1] talks about this too:

> Elementary art education materials, dictionaries, and electronic search engines often define primary colors effectively as conceptual colors (generally magenta, yellow, and cyan; or red, green, and blue) that can be used to mix "all" other colors and often go further and suggest that these conceptual colors correspond to specific hues and precise wavelengths. Such sources do not present a coherent, consistent definition of primary colors since real primaries cannot be complete.

[1] https://en.wikipedia.org/wiki/Primary_color