I generally specify followspots for tours where the artists are expected to walk around the stage, though I am generally not really a fan of followspots. The colors are finicky, the spots themselves are generally not maintained well – a venue typically bought their Super Troupers from Strong back in the ’70s, and hasn’t upgraded since, letting the components rust and get sticky, etc. Typically, followspotting is given to the crustiest, lowest-on-the-totem-pole guy on the call, usually not the person who would be best suited to making fine physical movements.

Did I mention the colors are finicky? Lamps for these things are designed for raw power, and if the color is going to drift, it always seems to drift to an unpleasant green. On a whim the other day, I decided to see what would happen when I combined a Rosco half minusgreen and a half CTO with the venue’s (admittedly very nice) Robert Juliat followspots. The results were gorgeous. The light looked almost tungsten, and I’m sure to the audience it was indistinguishable from the actual tungsten sources shining on the band behind Alan.

The problem with combining gels, of course, is that it cuts down on output, and also requires the person loading the boomerangs to keep track of two whole things at once, and so isn’t a truly ideal solution for the color issue with spotlights, so today we’re going to look at some colors that might do the job in place of an actual custom-engineered gel.

First, let’s look at the emission spectrum of a typical 2000-watt HID source:

I was a bit surprised to learn that xenon lamps have a very even spectral distribution in the visible wavelengths, much smoother than I expected. (They get very peaky in the infrared, which means they’re turning a lot of their energy into heat, but that’s a discussion for another day.) But it makes sense: they use xenon lamps in projectors for movie theaters precisely for that reason – you need accurate color rendering on the Big Screen, and big magenta / green shifts are going to be a big no-no. The green that I’m used to seeing in followspot lamps, then, is either because whatever followspots I’ve been using aren’t using xenon lamps, or there might be something else at work – color shift as the anode and cathode burn away and the lamp draws more power to make the arc. Or, it could just be that I find a source with less green in it to be more pleasing, and this is probably the answer that makes the most sense.

Personally, I could never understand why Rosco 33 was always specified as a followspot color by itself – I always thought it just pinked up the light without doing anything nice for skin tones. But as I’ve recently discovered, add a bit of amber, and you have a very nice color, apparently even when using xenon-based lamps. Now then, to find that magical gel color that will warm things up a bit while having a hopefully narrow-band dip in the green wavelengths. (This might not actually be what I want, but that is the reason one experiments!)

I looked in vain for some sort of emission spectrum calculator tool online that would let me input some emission curves, specify the source’s temperature in Kelvins, and get a rough idea of what the color I am looking for would look like. Alas, such a tool is not to be found. So instead, I went the tried and true way of cutting pieces of gel out and sticking them together in front of my computer screen while thumbing through LEE and Apollo swatchbooks for a match. Combined, the filters make a sort of…very light taupe-y dirty mauve color. (PS: I know my computer screen isn’t a good approximation of a xenon source, but I’m matching colors, not looking at their effects.)

LEE 154, Pale Rose

This is close-ish, though my color (Which henceforth shall be called Craig’s Magical Corrector, or CMC) has a bit more blue in it. 151, Gold Tint, is even closer, but still not quite there.

Apollo 7630, Peach My Interest

Pretty close to LEE 154, still not quite what I’m looking for.

LEE 747, Easy White

This actually has less violet and blue energy than the first one, and is about 50% too saturated for what I need. LEE says that this color was developed for fluorescents, so the reduction in blue and violet makes sense along with the green, but it’s too saturated.

I don’t have my Rosco swatchbook on me, but I think they make a color (Rosco 99 if I remember correctly) that’s fairly close to this, but less saturated, so that might be my ticket. As mentioned before, this is all experimental, and I’ll play with these colors at the next few shows where I have some high-powered spotlights and see what I can come up with. On a whim, I e-mailed LEE, and asked about a color close to what I’m looking for, which they said doesn’t exist.