Resolve Primaries and/or Log Color Wheel

Morning all

In resolve when you go to the colour wheels you can either select log or primaries and then based on that you can control your shadows mids and highlights or lift gamma and gain

my question is what is the difference between correcting in log or correcting in primaries mode?

They both work independently from one another. So you can make an adjustment in both and resting one does not reset both. This is important to remember because you might had made and adjustment in the Primaries then flipped over to Log and forgotten that you'd made changes in the Primaries.

The Log wheels work differently to the Lift Gamma Gain in that they are mapped differently to the the image tonal range. The Log wheels can also be set to affect more specifying areas. So you could for instance restrict the range that the Shadows wheel affects by changing the Low Range value.

The Log wheels are especially useful when working with Log footage.

The manual covers this in detail from page 407.

Thanks Adam

So when you say works best with log footage you mean footage just with the bmdfilm lut applied and not a 3d lut on top?

I did notice how differently they affected my footage. This was footage with the bmdfilm lut and then a 3d lut already applied though...all on a single node.

I managed to get the image I wanted...just wasnt exactly sure the difference between the two modes.

Log footage would be footage like the ProRes Film mode from the BM cameras or CinemaDNG developed in BMD Film color space. Other cameras can also produces Log footage.

Because the footage is in Log color space the Log corrections wheels will be more useful in correcting the footage due to how they are mapped to the tonal range.

As for the 3D LUT, it all depends on where you are applying the LUT. Remember that LUTs were never designed for creative grading, they were intended as a means of translating color from one color space to another. LUTs used for "creative looks" can return very odd results if the input is not the same as the LUT was designed for. As an example try applying a creative LUT that was designed for Log footage to some Rec709 footage and the you'll see that the results are completely different. So it's important that you balance your shot first.

In most cases you should apply the LUT after any corrections (especially "creative look" LUTs). So either set it as an Output LUT in your project settings (this is best if all footage in your project is from the same source) or apply the LUT selectively to each clip by placing it on the last node (using the first node for primary color correction, 2nd/3rd/4th/etc nodes for secondary corrections).