A verb meaning "to make a color brighter or darker"

I am writing a function which takes in components of a color (as red, green, blue component values) and makes the color brighter or darker based on the fraction that the developer provides. If the fraction is less than 0, it makes the color darker, if the fraction is greater than 0 it makes the color brighter. I am struggling to find a concise, preferably single-worded name for that function.

I have looked at some words that are relevant, such as lighten, darken, illumine, shade, and tint, but all of these tend to imply either making the color brighter or darker, but not suggestive of the possibility of both.

I would appreciate any ideas. Thanks.

Why not keep it simple? These are both two words, but it's concise and semantic:

function adjustHue(fraction) {} - This suggestion describes a change in the color itself, which is more technically correct but perhaps less semantic than the alternative, luminance. It is more technically correct because adjusting luminance of an RGB color requires changing the color's RGB value, which is, by definition, changing the color's hue.

function adjustLuminance(fraction) {} - This suggestion isn't technically accurate but might be more semantic because luminance describes the perceived brightness of a color. You can determine a RGB color's luminance by applying a formula to the RGB values. See this question for more info: https://stackoverflow.com/questions/596216/formula-to-determine-brightness-of-rgb-color. Note, though, that in order to change luminance for an RGB color, you must change hue.

In photography, the term exposure is used to talk about the "light intensity" on photo objects. A photographer may "change or alter exposure" to adjust the light intensity, so they can get brighter or darker images/colors.

Why not borrow it?

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