When you’re starting out as a programmers, choosing a profile can be confusing.  Why would you choose one over another?  I always favor profiles that give me direct control of all attributes and I favor 16 bit profiles when I can.  Let’s talk about the 8 bit vs 16 bit preference in case you are wondering “why bother with 16 bit?”

8 Bit

In case you’re not already aware, an eight bit value has 256 steps of resolution.  What does that mean?  It means the bottom value is zero and the highest that an 8 bit value can reach is 255.  In the case of intensity, that means we move 2.55 DMX values to go from 0 to 1 and from 1 to 2, etc.  When all of lighting was dimmed incandescents, this was fine.  But the moment you add other parameters, it’s not so great.  I’m going to provide two examples (one for Live entertainment people, one for film people) to drive this point home.

Live: Almost every moving light in the world is capable of panning 540 degrees.  Imagine moving one DMX value and the light pans 2 degrees.  If this doesn’t stress you out, place the light 100 feet from the stage.  Two degrees is a big move now, right?

Film: Most film lights can go from 2000 CCT to 10,000 CCT.  That’s a travel of 8000.  8000 divided by 256 is 31.25.  Every DMX value change, you are jumping 31.25 CCT.  You will almost always be a bit above or below your target CCT. 

16 Bit

16 bit values are made by multiplying an 8 bit value by an 8 bit value.  This is why 16 bit values use 2 addresses in DMX.  What’s 256 times 256? 65,536.  So the bottom value is still zero, but the top value is 65,535.  In intensity, that means you have about 655 steps between 0 and 1.  Imagine using an S360 really close up.  Suddenly, having all that resolution between each value might be useful.  My gaffer regularly calls for intensity at half values with big lights. So obviously, CCT, Pan, Shutter cuts- every 16 bit value gives you the chance to be so much more precise.  And precision is kind of what we are hired for as programmers.

Parameter Count- the Buzz Kill

In an ideal world, we would just have every attribute in 16 bit, right?  Well, yes but no.  Why? Because our consoles have limits to how many parameters we can unlock.  So in a way, we need to “spend” parameters like money…because it is.  If you have a 64 universe setup and you don’t work with tons of pixels on huge installations- you can have 16 bit everything!  But on several projects I’ve worked on, 64 universes fills up FAST.  And then you have to play the value-proposition game of giving up resolution to simply be able to control everything you need to.  Which means you need to carefully decide what attributes you NEED 16 bit control over and make a calculated risk on the rest.  In general, lights that point AT people should be in 16 bit.  Lights that point at the camera or audience can be 8 bit, if you need to find a place to cut down your parameter count.

No Easy Answers

As with most things in life, there is no easy answer to “should I choose 8 bit or 16 bit”, but hopefully this helps you understand what is at stake in either and how to make some tricky decisions.  If you’re already used to making these decisions, what informs your decisions?  Hit me in the comments.

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Mark LaPierre is a programmer in film and television based out of Albuquerque.  He grew up in live entertainment and has been a designer/programmer for musicals, concert dance, live music, circus and corporate.  Mark is a proud member of IATSE, an ETC Eos trainer and an enthusiastic trainer of many other platforms and subjects.  If you enjoy his content, please consider commenting on his posts on the website to appease the Algorithm.