Does a colorist control surface use different math compared to a mouse?
The most intimidating presentations I give involve color correcting in front of a live audience
I often find that my carefully prepped material doesn’t quite ‘grade up’ the way I expected, when doing it live. It seems I’m making more ‘moves’ and feel a little sloppier than when I’m grading in the comfort of my suite. I’ve always chalked it up to a combination of nerves and being in a terrible color correction environment. Except I recently discovered… maybe it’s not me. Maybe DaVinci Resolve is changing its color correction math when I’m up on stage???
What? How can the color correction math change when grading in front of a live audience?
It makes no sense, right? But a recent Tweet by Jamie Dickinson to my Twitter account directed me to a forum thread he started:
— Jamie Dickinson (@dickij10) September 9, 2016
Click on his link and you’ll end up at LiftGammaGain where Jamie poses a simple problem:
- If he balances a highlight using the mouse, and then lifts the Gain with the user interface Wheel – the color balance gets thrown off
- If he balances the same highlight using a control surface and then lifts the Gain using the control surfaces’ Wheel – the color balance is maintained.
My first reaction: There’s a problem with his system
But as I read his post and his subsequent follow-up questions to people who responded to him, he’s quite lucid. He’s able to replicate this problem on-demand. So I decided to follow the steps he outlined.
You know what?… the color correction math between a control surface and a mouse IS different!
I was able to perfectly reproduce his results. In fact, I took his test a bit further and determined that the math in the Lift and Gain Primary Wheels is very different depending on your input device—mouse vs control surface. (I found the Gamma math to be the same between the two different input devices)
Unfortunately for mouse users, most of the time you’re doing more work than control surface users
As you’ll see in the video below, on typical color correction tasks the behavior of the control surface is more desirable. Control surface moves for the Lift and Gain operations completely eliminate the back-and-forth movements that mouse colorists are forced to endure.
I’m saddened to say, DaVinci Resolve does make mouse-based colorists feel more un-talented than their control surface peers. It probably also feeds into the color grading newbie’s feeling that color correcting takes too much work; since they’re almost certainly starting with a mouse.
This also explains why I feel un-Talented color correcting in front of a live audience
The color correction moves I’m used to making are all done with a control surface. But when I take footage that I’ve graded professionally in my grading suite and re-create them for a live audience… I usually choose to use a mouse (since it’s easier for the audience to follow a mouse and see my moves).
Moving to the mouse changes the color correction math—and those simple color correction moves on a control surface take a lot more work to duplicate using a mouse. Suddenly I start struggling. And, until now, I never understood why. Thank you Jamie for helping me discover I don’t suck at color correction… it’s just the software making me feel that way!
But the ‘control surface math’ isn’t always better than the ‘mouse math’
As I pushed my testing of this ‘bug’, I discovered the differences between color correcting on a mouse vs. a control surface go deeper than just using the contrast wheels. The Color Wheel / Trackball inputs also give us different results for the Lift and Gain tonal controls.
And with extreme color balance problems, the mouse behavior is actually better. On extreme corrections the mouse is MUCH more gentle on our images and the control surface behavior is terrible!
If you want to see what I’m talking about – watch to the end of the video
I’ll also share my thoughts on how you can use this knowledge in your day-to-day work. And if you think this is something that needs to be fixed (which I do—unless there’s some rock-solid logic behind all this), you can post on Blackmagic’s forum or directly contact them using the Email form at the bottom of their Support page.
Seriously, while we always welcome comments here on Mixing Light – when it comes to bug fix requests and feature requests, the Resolve team doesn’t care what I say or think. They care about what hundreds of us say and think. If you want Blackmagic to unify the mouse and control surface behaviors follow the links I just provided and… say something.
Download my DaVinci Resolve test project
This project file should be opened in DaVinci Resolve 12.5.2 or later. You can recreate and deconstruct what I’m doing in the video:
P.S – I do apologize for the noise in my on-camera setup for this Insight. I’ve started testing new lights and I seriously under-exposed myself 🙁 I really need to start using a light meter!