After testing several, I thought Cobalt Blue (i.e. close to hex code 0000FF) was the closest a true primary blue, Pyrrole Red (FF0000) close to a primary red. I found a yellow called ‘primary’ yellow (it's somewhere between light to medium).
Mark’s limited palette uses a darker blue and a darker red (even though the yellow seems close to a primary yellow). So my question is (probably a dumb question) Why?
Is it to prevent the temptation to end up painting with colors that are too bright? Is it better to mix with primary colors that are ‘dirty’ to avoid this - even though there may be slight traces of other colors in them (i.e. green, etc.)?
In theory, it shouldn’t matter how you get there, but real life I’m sure there are good reasons for his Geneva color selections. The videos I have seen so far don’t seem to directly address this issue.
(For beginning projects and mixing practice and I'm going to use up what have. If I make sufficient progress I'll consider investing in Mark's Geneva colors.)