Professional Color Grading Techniques in DaVinci Resolve

11 hours ago, James Lakey said:

In "Color channel mixing to create unique looks" you seem to know what numbers you want to put in the outputs of the various channels in the RGB mixer already. Where did those numbers come from? Is that often a combination you use? As someone that never uses the RGB mixer, I was a bit baffled at how you chose the numbers, even though I could see the overall effect.

I had the same question, so I opened up the clips, set up the node tree, and started playing.  At first it appears to be somewhat magical, but it suddenly makes sense with an RGB waveform monitor (or an RGB parade scope) and a vectorscope.  What I noticed is that when the Red output is fed also by the Blue channel, the vector scope show everything being pulled and stretched toward the R target.  When the Green output is fed also by the Blue channel, the red-stretched blob rotates and stretches toward the Yl target.  You can then watch the magic happen as you rase the Green output into the Blue Channel.  What was a large outstretched limb of color pointing towards Yl squishes very quickly to a very thin line that points between R and Cy.  Those two complementary colors provide a credible balanced look that simply has no other colors to it--no Mg, no B, no G, and no Yl.  But that narrow balanced line is not aligned with the skin-tone line.  This can be fixed by rotating the Hue, or by subtracting Red output and re-adjusting Green output to get back to the thin wispy line.  When the remaining colors are aligned with the skin tone line, the skin tones look natural, and the balancing complementary colors on the other side of the center make the look.  I got this with the following

Red Channel: 1 R + 0.9B

Green Channel: 1 G + 0.9B

Blue Channel: 0.91 G + 1B

Hue Rotation: 43.4

Without Hue rotation I got the lines to line up with Blue = -0.5 R + 1.41 G + 1B

When I raised the Green output to 2.0 I needed to drop Red to -1.07 and I observed the need for a Hue rotation of 53.30 to get back to the skin-tone line.  I also noticed that using larger numbers in the Blue output channel results in greater saturation, which may or may not be desirable.

But I think that the fundamental operation we see here is using the RGB Mixer to take us from 3 colors to 2 while letting the skin tone be the skin tone.

I will also say that it is INVALUABLE to have a Resolve Mini panel with which to be able to twiddle two knobs that send the colors in opposite directions so that one can maintain the target of the skin tone line while seeing how all the other colors react to various parametric alternatives!

Amazing! you have managed to explain the most complex in color grading in a way that is easy to understand, and I must say that this course is in its very own league. I'm also happy to see that you did a whole course without  pulling keys (except tonal keys which is a must) and unnecessary use of secondaries. This truly is a best-practice course that values the base grade and the lessons are super tight! 

I must say it's a BOLD move to do a full color grading course working only prior to a LUT. But hey, it's the way it's done by the Pro's !

Fantastic course.

The show cased workflows rely on one key element though - corrections prior to the Log to display LUT. Easy enough when you rely on LUTs to do that. However, increasingly we're using either ACES or TrueColor in Baselight which create a different setup and already make some major changes to the footage before we even get to do grading operations.

So, are there different techniques when working under those conditions? Or would we have to force work around by bypassing the IDT and then applying it later in the node tree? Or in Baselight, not selecting the camera color space in layer 0 but then later in the stack identifying the layer color space to trigger the conversion and allowing us to have a go at the footage first?

I prefer the flexibility and quality of the IDT and TrueColor transformations over using LUTs. So it would be nice to reconcile this.

On 2/17/2020 at 6:31 PM, MichaelTiemann said:

I had the same question, so I opened up the clips, set up the node tree, and started playing.  At first it appears to be somewhat magical, but it suddenly makes sense with an RGB waveform monitor (or an RGB parade scope) and a vectorscope.  What I noticed is that when the Red output is fed also by the Blue channel, the vector scope show everything being pulled and stretched toward the R target.  When the Green output is fed also by the Blue channel, the red-stretched blob rotates and stretches toward the Yl target.  You can then watch the magic happen as you rase the Green output into the Blue Channel.  What was a large outstretched limb of color pointing towards Yl squishes very quickly to a very thin line that points between R and Cy.  Those two complementary colors provide a credible balanced look that simply has no other colors to it--no Mg, no B, no G, and no Yl.  But that narrow balanced line is not aligned with the skin-tone line.  This can be fixed by rotating the Hue, or by subtracting Red output and re-adjusting Green output to get back to the thin wispy line.  When the remaining colors are aligned with the skin tone line, the skin tones look natural, and the balancing complementary colors on the other side of the center make the look.  I got this with the following

Red Channel: 1 R + 0.9B

Green Channel: 1 G + 0.9B

Blue Channel: 0.91 G + 1B

Hue Rotation: 43.4

Without Hue rotation I got the lines to line up with Blue = -0.5 R + 1.41 G + 1B

When I raised the Green output to 2.0 I needed to drop Red to -1.07 and I observed the need for a Hue rotation of 53.30 to get back to the skin-tone line.  I also noticed that using larger numbers in the Blue output channel results in greater saturation, which may or may not be desirable.

But I think that the fundamental operation we see here is using the RGB Mixer to take us from 3 colors to 2 while letting the skin tone be the skin tone.

 

I will also say that it is INVALUABLE to have a Resolve Mini panel with which to be able to twiddle two knobs that send the colors in opposite directions so that one can maintain the target of the skin tone line while seeing how all the other colors react to various parametric alternatives!

There some visuals that help with understanding color matrices here.

https://ciechanow.ski/color-spaces/ 

Did anybody notice when working with RED footage in ACES workflow vs applying the REC 709 IPP2 lut there is a contrast and hue difference? Easily noticeable in skin tones.

Great addition to the Lowepost courses.   As a career cinematographer, the "hands on" I've been able to accomplish with my own DaVinci set up has been wonderful.  Learning from colorists like you has sped the process and shortened the learning curve.  Any chance you can add to the course with some BlackMagic RAW workflow tips?  Thanks so much.

At the end (5:00) of lesson 12 about mixing colors, Kevin mentioned that"you can add a third color into the mixing, and get another set of color called  'toushiery(?)' color... So what is the exact  word he used?

7 hours ago, Qiang Tang said:

At the end (5:00) of lesson 12 about mixing colors, Kevin mentioned that"you can add a third color into the mixing, and get another set of color called  'toushiery(?)' color... So what is the exact  word he used?

Tertiary 

On 2/22/2020 at 9:41 PM, cameronrad said:

Tertiary 

Thanks！

Tertiary World is where I come from  😀