I've recently become interested in the primary colours; red, green and blue.

In my capacity as a computer programmer I'm well aware of how these colours are used practically, and of how varying combinations of the three can produce any colour visible to the human eye.

However, it occurs to me that these are essentially three evenly spaced frequencies on the visible spectrum. I don't know of any scientific reason why these colours are used to combine light, or if they are distinct in any way.

• does anything measurable distinguish primary colours from other colours?
• could the same method be used to produce any colour from, for instance, yellow, cyan/teal and magenta light?
• is it possible to produce any colour on the visible spectrum by combining just two other colours?

I've recently become interested in the primary colours; red, green and blue.

In my capacity as a computer programmer I'm well aware of how these colours are used practically, and of how varying combinations of the three can produce any colour visible to the human eye.

However, it occurs to me that these are essentially three evenly spaced frequencies on the visible spectrum. I don't know of any scientific reason why these colours are used to combine light, or if they are distinct in any way.

• does anything measurable distinguish primary colours from other colours?
• could the same method be used to produce any colour from, for instance, yellow, cyan/teal and magenta light?
• is it possible to produce any colour on the visible spectrum by combining just two other colours?