Color drift on ETC Source 4 LED Fixtures

Darin

Well-Known Member
I'm working in a theatre that has an array of Source 4 LED Ellipsoidals (not sure which series). Some of them appear to have correct color mixing (they are "true" to the colors I'm selecting on the Ion XE console) while others look like they are drifting green. In other words, if I go to a primary blue color, some are blue, while others are more cyan. If I go to red, some go more "tomato". If I select a basic white, some are tinged slightly green.

They all have the same profile in patch, so I'm not sure what's going on. It's not my space, and I don't have access to the fixtures (they are on dead-hung pipes that are currently inaccessible due to onstage scenery).

Any ideas what's happening here?
 
There's a million settings in the modern units that might effect this, so make sure all settings are the same. It's also worth checking to see if the units are the same age/model. I know that I was in a venue a few years back and had two different generations of d40s with the newer ones noticably different in intensity from the old ones due to manufacturing adjustments on etcs end. It's certainly possible you have a similar situation, one of the downsides to leds
 
RDM is "Remote Device Management" a protocol that allows the console to send and receive data from fixtures, such as their various operating modes, their DMX address, error conditions, etc. Assuming your DMX distribution is compatible with RDM (lots of older equipment gets confused by the RDM packets on the DMX so any opto splitters have to be compatible) you can get and set from the fixture using Concert (accessed on the Maintenance tab from the settings menu (exit EOS to the shell to get there) This will allow you to see the fixtures setting without having to physically access the fixtures.

Is this any clearer mud?
 
Two thoughts related to possible fixture issues-

Maybe some of the LED's or drivers have failed and the color is distorted as a result of it not having enough LEDs working? If say, a handful of the reds are out, your yellows/ambers are going to pull more green. I'm not familiar with the LED array on those fixtures so I couldn't tell you specifics, but I would pull a couple and inspect it.

The other thing, and perhaps less likely because it's ETC, but I have seen different models of the same fixture purchased at separate times have color matching issues. The apocryphal tale I've heard is that all of the LED's in the universe come from like three factories in China, and slight deviations in the process can affect different runs of LEDs. I've seen it with Blizzard RokBoxes, as I've got two sets that were purchased a year or so apart and the white LEDs are noticeably different color temps.

Again, I'm willing to bet ETC spends a bit more on sourcing LEDs than Blizzard, but it's possible you would notice a difference between fixtures from different manufacturing runs. Not to mention color shift in LEDs over time is a thing.
 
Again, I'm willing to bet ETC spends a bit more on sourcing LEDs than Blizzard, but it's possible you would notice a difference between fixtures from different manufacturing runs. Not to mention color shift in LEDs over time is a thing.

Yup, binning is a thing. When LEDs are manufactured there's inherent variation in the process, so each batch is sorted into "bins" that have specific characteristics of brightness and color accuracy. Better manufacturers are picky about consistent binning. Lesser manufacturers take whatever is cheapest that day/month/whatever. Also, ETC calibrates each fixture to have consistent color and output--but only when running in a mode that uses this calibration. HSI does, Direct doesn't for example. Individual fixtures can still drift away from each other over time as different levels of usage age the LEDs differently. Here too, better manufacturers reduce this effect by not pushing the limits of the LEDs (at the expense of a little less brightness).

At any rate, the first step here is definitely to identify what mode each fixture is in and make them and the console patch all match. Only from that starting point can you really tell whether they're not doing what you tell them, or whether they're just not understanding you because you're speaking a slightly different language.
 
Depending on what model you have, there are more options in the menu not available on RDM. Specifically Color Temp, and one other one that drives the led output. It’s listed under advanced settings on the unit. Basically make sure they all match between all your fixtures.
 
remember, he did say "and I don't have access to the fixtures (they are on dead-hung pipes that are currently inaccessible due to onstage scenery)." so that's why I sugguested RDM.
 
As a sidenote, is there a way to create an offset for fixtures that are behaving odd?
So like if, in the OP's situation, there's 5 fixtures that edge green. Kind of like a pan-tilt invert, is there a way, per fixture, to tell the console that you want -3 G or something?

I've even been messing with this on a church that has dot2 on PC with a couple moving lights. At some point someone replaced a some broken CMY glass in one fixture but M and Y's position are flipped.
 
As a sidenote, is there a way to create an offset for fixtures that are behaving odd?
So like if, in the OP's situation, there's 5 fixtures that edge green. Kind of like a pan-tilt invert, is there a way, per fixture, to tell the console that you want -3 G or something?

If it's an LED aging issue, then specific fixtures would have less output than others for specific colors. That means you would either have to limit that one color in every other fixture in the rig to match the one that's off, or you would have to limit every other color in the bad fixture so you get approximately the same mixed colors--but at a lower intensity. Either way, it would be pretty messy to try to balance. The best bet would be to group fixtures that have similar performance and use them together wherever possible.

In some ways, having a consistent rep plot might make this less of an issue overall. If you use a lot of blue in your top/backs, then in a few years they might not match your sides as closely, but they should still be relatively similar to each other. Maybe we need scheduled fixture rotation added to the preventative maintenance list to even out the wear (if, say the fixtures focused center get used more than the ones around the edges). Maybe it's not worth worrying about...
 
Somewhere in distant memory a voice says you can recalibrate Lusters.
Naturally that would require ETC tech support!
 

Users who are viewing this thread

Back