Red and blue make...yellow?

[Sparky_911]

Random weirdness...experimenting with lenses and colors, fluting, etc for some videos and discovered this. Yellow....created by a RED libby head and a BLUE MX7K snap on filter. Just odd that it didn't go purple.

 

[RS485]

This is a really interesting topic but I don't know "jack" about it.
I came across this:

Color Addition & Subtraction

www.surendranath.org

which _might_ be helpful in learning more