Earlier in the week, I had one student who had been told by her instructor that 80% of a painting should consist of white paint. I disagreed with that, since whenever I use a lot of white, I get cold, chalky paintings. (My mentor, Ann Templeton, says white is the "killer color.") I couldn't imagine why anyone should want to use so much white.
So today, she said that her instructor also told her that Cadmium Yellow Light is a warmer color than Cadmium Yellow Deep. I disagreed with that, too. CYL has a bit of blue or green in it, whereas CYD has red in it. But after a little experimenting, we think we discovered where this information was coming from.
Imagine three colors: Cadmium Red Light, Cadmium Yellow Deep and Cadmium Yellow Light. Now, lay down three stripes of these colors, going from bottom to top with CRL, then CYD followed by CYL. The CRL looks closest to you because it is warmest; CYD looks to be out in the middle ground, and CYL looks to be farthest away because it is cooler than either of these.
However, the values are different. CYL is very light, CYD is dark, and CRL is very dark. If you adjust these values with white - and it takes a considerable amount to make the CYD and CRL as light as the CYL - the white kills the warmth. Suddenly, with the values adjusted, the CYL does indeed seem the warmest and thus, the closest.
In my mind, neither of these two approaches is right or wrong, so long as one remembers that the warmest color will always come forward. I would still advise caution when using white, though. I'd be interested in hearing your thoughts.
In the meantime, here are two little pastel studies I did from the studio, looking out into the rain. ("Sun'n'Fun" is the resort where our workshop is based.)