Ah, you've discovered the joys of secondary color mixing! The High End Studio Spot, like many other lower-end or cheaper moving lights, just has a color wheel (or in this case, two). This is just a wheel with five slots (plus one for open) that you can put pieces of colored glass into, then you just tell the wheel what color to move to. This is easy and cheap, but it really limits how many colors you can have, and crossfading between colors is chunky and not smooth at all.
What the VL1000 has, similar to most other higher-end moving lights, is a three-wheel Cyan Magenta Yellow (
CMY) color mixing
system. Each manufacturer does this slightly differently, but basically, this
system is made up of three separate glass wheels, one each for Cyan Magenta and Yellow, that have a gradient from totally
clear to full saturation of the color. Each wheel is controlled individually, and as the wheel rotates, the more saturated parts of the glass wheel enter the beam of light. When the
unit is in
open white, the
clear parts of each wheel are rotated to be in the beam of light. As you increase the value of the Cyan wheel (for example), it rotates and as it does, the higher saturation parts of the wheel start entering the light beam until the color is at its maximum saturation. When you select a color from the
color picker or similar, you're just telling the three color wheels to go to specific values. Most people much prefer this
CMY mixing over a color wheel - however, there is a slight disadvantage in that it's difficult to precisely match a specific color.
The VLX is a pretty cool new piece of equipment. It works on a four-color mixing
system, mixing Red Green Blue (the primary colors of light) and White. By varying the relative intensities of each color, you can achieve a very wide range of colors. This works with LEDs much better than if you just set up three lights in Red Green and Blue because unlike with
incandescent lights, dimming the LEDs doesn't result in any kind of
amber drift that muddies up the color.
Vari-Lite has done a great job at mixing the
LED colors inside the
fixture, allowing for a
zoom function and eliminating the color shadowing often seen with cheaper
LED units. Also, because they're LEDs, they almost never need to be replaced, there is much less heat generated (meaning less cooling fans, and therefore less noise), and the
power consumption is considerably lower. We had a demo of the VLX here a few months ago, and it does a great job at doing what it's intended to do, but there's still a long way to go in the development of LEDs.
, it's "subtractive," not "secondary" color mixing. The secondaries of one color mixing 
