In the Format toolbar,
click on layer property Manager
In
the layer property Manager dialog window, select the layer to be modified.
In
the Color dialog window, perform one of the following operations:
In
the Index tab, click on a color or insert a color number (index from 1 to 255). Click
on OK.
Double-click
on the color window to access the True Color tab. Choose a color typing its RGB value
or entering specific values in the Hue, Saturation and Luminance boxes; then click
on OK
Click
on OK again to close all the dialog windows.