JD750 Loc: SoCal

Recently I saw the following regarding how to select a neutral color for a white balance (WB) adjustment when using the ubiquitous dropper tool.

“If you don’t actually have grey in your image at all, you’re looking for a neutral color. You can identify the color you’re hovering over with the dropper as a neutral when then three R, G & B values are about equal.”
Source: https://digital-photography-school.com/3-ways-to-change-white-balance-in-lightroom/

My question: if WB is incorrect in the original then would not a neutral area exhibit a color shift and thus not show equal R,G,B values?

terryMc Loc: Arizona's White Mountains

I think your question was answered in the first comment to the article—simply using the eyedropper to measure color does just that, measures the colors under the dropper. If you get "about equal' colors you are measuring a neutral, and that means some shade of gray. If there is a color shift, you will see more of that color in the measurement. What the author should have said was that you pick an area that you know or think should be on the white-to-black spectrum and then click that area with the white balance dropper. It will remove the prominent color from your sampled area and change that balance globally. Depending on the area you sample this may effect a different undesirable color cast over the image, e.g. taking out red may make the image too cyan.

JD750 Loc: SoCal

Right! Thank you.

If I shot a neutral grey card in warm light it would not be equal RGB it would show more of the warm colors.

terryMc Loc: Arizona's White Mountains

Yes, and then you would use a white balance tool to click the grey card to get the neutral white balance.