is it possible to add color3 to a part's color?

i'm trying to make a fire that smoothly darkens the part until it's black, however when i try to 'add' color3 it just says: 'attempt to perform arithmetic on field 'Color' (a userdata value)'

sample code:

script.Parent.Color = script.Parent.Color + Color3.new(0,0,100)

is there a way this is possible?

You can, but the problem is that you can't apply arithmetic in UserData values.

script.Parent.Color = Color3.new(0,0,100)