Color Force Steppy Dimming

Colin

Well-Known Member
Joined
Jan 23, 2015
Location
Eastern Massachusetts
I have some Color Force 72s and 12s picked up used and have found the bottom of their dimming gets very steppy with slow timing. Wondering if there's really something wrong or if this is normal behavior for them. Used as a ground row, they're so bright that sometimes they'll be in a cue at 10-15%. Use a 6+ second fade up from zero on that cue and the steps are very noticeable - makes them unusable to me. We got through a couple of shows without noticing it since at higher intensities the problem is masked/nonexistent. You have to be fading at a rate of maybe less than about 3-5% per second while crossing below 12% intensity to really see it. A variety of different modes and data runs including direct to our Ion doesn't change things.
 

DrewE

Well-Known Member
Joined
Mar 18, 2019
Location
Vermont
10% intensity means you have about 25 steps between off and on, since DMX values have an eight bit range (i.e. integers from 0 to 255). Steppiness is pretty much inevitable in that situation unless the fixture is doing some interpolation on its own, and particularly at slow fade times it would have no way of guessing whether you want a continuous fade or multiple steps up.

One potential solution may be to use one of the modes that has an intensity master and set the component levels to your final brightness and then fade the intensity master from 0 to full on. There still may be steppiness depending on the internal resolution of the PWM drive system used by the light; digital controls are, after all, quantized, and you can't get increments smaller than one of those internal quantization units. Another solution might be to put some sort of neutral density gel or other intensity-reducing media in the path of the light (and so use more of the light's brightness range).
 

Colin

Well-Known Member
Joined
Jan 23, 2015
Location
Eastern Massachusetts
Yep I realize that's beginning to stretch the resolution of the fade but it just seems like way less than 25 visible steps from 10-0 and the rest of our LEDs (all models of ColorSource and Lustr II) do way better, so wondering if they're just doing way better because they're way better at the doing, or if this CF behavior is unusual for the fixture. The neutral density option is my present solution, but it's a real pisser when you have an application that calls for the full intensity range of the fixture. It has been a while since I ran through all the modes. The RGBI ones might be better. I should try again. I've been in HSI and RGBA lately.