Hi:
The first (and perhaps only) time I saw a pro laser show what struck me was the colors which didn't correspond to any wavelengths I knew from the scientific lasers with which I was familiar. In particular there was a blazing lemon-yellow (not the yellow-green Kr-ion 568nm, but true yellow), and purple colors which particularly puzzled me because they didn't look like anything which could happen with a pure spectral color.
At the time my understanding of color mixing was non-existant, so it didn't occur to me that the yellow and purple were simply the result of mixing colors from the Ar and Kr laser wavelengths that I knew. (This was before DPSS had become commonplace). I've also spent some time studying the CIE x,y color space, so I now undertand the difference between purple and violet.
In recent weeks I've viewed quite a few images on this site of RGB projectors based on DPSS & diode lasers emitting typically 635nm, 532nm, and 473nm. What puzzles me now is that I have yet to see solid yellow, orange, and purple colors. All the rainbow-like color sweeping beam effects I've seen appear dominated by RGB, with narrow transitions between the colors that don't give any strong impression of a bold orange & yellow between the red and green, nor a good purple. (Though, I have seen a bit more purple than the yellow and orange).
I wonder what is going on here? Is it that the photographic processes are not responding well to the colors because the wavelengths defining the color gamut don't agree with the RGB filter properties in the cameras? (I doubt this is the issue). Or is there a linearity problem with the analog modulated lasers? Or perhaps there aren't really many analog lasers out there, and most are TTL?
The linearity question is my greatest interest. Has anyone put their laser on a high-quality wide-bandwidth photodiode receiver and fed the laser a triangle or sawtooth waveform to see how linearly the output varies with input voltage? This will be one of my first tests once I get my next laser - a 473nm variety.
I hope to produce well balanced rainbows of colors with clearly defined oranges, yellows, and purples once I get my projector together.