I tried to make several radial gradient fills to single rectangle, but unable to make them all visible in the same way. I tried different "blending modes", but was unable to find required combination.
I need three light spots in different places in the picture below.
How to do that?
Grey rectangle, black type.
Gradients are applied as additional fills for the rectangle (under the type)... white 100% opacity to white 0% opacity gradient fills...
This keeps type visible and readable while highlighting specific areas... No blending modes necessary, but you could use blending modes if you want.
Just move the box above the type and set it's blending mode to Multiply.
One more:
There's black text on white background in the bottom. Above the text there's a group. (see NOTE1)
The group contains a grey rectangle and blurred white ellipses or circles. The rectangle and the blurred shapes have blending mode = Normal, but the group has blending mode=Multiply.
There's still black text and totally free form gradient light.
The rectangle makes the apparent text box color. The lights can be colored. You access the blurred items for edits inside the group either with the direct selection tool or via the layers panel. The blur effect can be opened for readjustment in the Appearance panel
NOTE1: This all is a bit complex but it works also if the text is an imported bitmap image or other piece where you cannot easily insert the lighted area under the text.
Type layer set to Normal Blend Mode
Grey rectangle set to Overlay Blend Mode
White Circles with Gaussian Blur applied (Effect>Blur>Gaussian Blur) set to Overlay Blend Mode
Notice background rectangle is a compound path so as to not be affected by Blend Modes
