I want to create a mask by drawing a shape over a person’s face so it isolates the face/skin tones so I only see the skin tones in the vector scope and histogram. If I now adjust the exposure or WB, is it only applying it to the masked area or is it applying it to the whole image? My goal is to use the mask only temporarily so I can make my adjustments to the selected area and then remove the mask after I am done. I am not clear on what it is doing.
The mask will limit the 'touch' to the area inside the mask, unless you click the ECP option to invert. IF the mask is setup and working as you want, the rest of the image will disappear from the screen.
One way to do something similar to this is create an HSL key for skin tones where that's the only thing you've done in Lumetri, with the HSL key mask showing in color/gray mode. Export that as a .cube LUT or as a preset. You'll be adjusting the whole image, but according to the needs of the skin tone. To follow this for adjusting skin only, simply do this in the HSL tab of your current Lumetri instance. That's simpler of course, and affects only skin tones. To correct the color within the HSL, use the one/three-wheels setup or the color balance sliders.
The following shows the basic setup:
First, you need a clip with a proper skin tone. You can actually correct for proper tone in one Lumetri instance, then apply a second below that one, and do this procedure in that second instance. I sampled the area circled in the cheek ... then set for mask on (check-box) and color/gray. Then adjusted the Hue, Sat, and Luma mid-point/range/falloff settings to get the most of the skin without other things showing much, then did some denoise and blur to get rid of artifacts/chatter, and ... do your correction in the color controls of the HSL tab ...
or ... with the above keyed mask set ... and ... saved as a .cube LUT, or you can also choose a Preset of this for a slightly different following workflow ...
With the LUT, put in the tech folder you create to store Tech LUTs now according to the following chart ...
... you can simply browse the Basic tab's Input LUT drop-down for this LUT you've named, and it will appear with the skin tone mask on. Check your skin tones in the Lumetri scopes & adjust ... if they fall outside the mask, adjust your color correction settings by your tool of choice until the skin falls back into the area you want.
Then simply remove the LUT from the Basic drop-down slot.
With a Preset, you'll want to probably apply this to Lumetri with either an adjustment layer and apply the preset to the AL, or apply it in a 'clean' Lumetri on the clip, then add a second instance of Lumetri, and do your work. Remove the AL or the earlier instance when you've got your skin adjusted.
If you use the Opacity Mask for the clip to crop out the extraneous content around the face, adjust the lumetri settings to color correct the face, then remove the mask, the color correction will apply across to the whole clip.
If you want to restrict the color correction to just the area of the face, but also take advantage of temporarily masking around the face so that it is easier to do the correction, then -
Set the mask up at Opacity Mask to crop around the face.
When done click on the mask name in the Effect Controls Panel and copy it.
Click on Lumetri Color effect in Effects Control Panel and select it.
Paste the matte you copied from Opacity.
Do your correction.
Delete the Opacity mask, now the color correction you have done will be restrained within the Lumetri matte.
I always had trouble with this as to the differece between the opacity mask and the lumetri mask. I am wondering could he have just not used the opacity mask and just use a lumetri mask and color correct with that. I ve seen many videos using the opacity mask to change the skin tone. But when I use it, it changes the skin tone and then when I delete the mask it just changes the whole clip to the color of the skin tone that I corrected....so you are saying...
do not use the opacity mask to change skin tone, use the lumetri mask and change it there???
If you've used a mask like opacity to limit the area an effect is applied to ... then remove the mask ... the effect will now be applied to the entire image. It can't work any other way.
This is why some effects like Lumetri have masks as part of the effect. You add an instance (easiest is simply the drop-down at the top of the Lumetri panel) then that instance of Lumetri is only applied to the area inside the mask ... unless you select the option to invert, where it is applied to the area outside the mask.
And of course, you will have options to track the mask if needed.