For objects that have a background you can apply additional graphics effects.
To apply graphics effects to the background
1. Select an object in the Project panel or on the Artboard.
2. In the Properties panel, under Effects in the Properties section :
3. Select the Effects checkbox to apply effects to the background.
You can specify following effects for the background texture :
Transparent color - it is possible to set a transparent color of the background. Select the checkbox Transparent color and choose the color using the select color button.
You can choose a transparent color similar to any pixel of the screen using the Pick Color function .
Hue, Saturation, Lightness - provides you tools to make corrections to the color and tone of images.