Enhance

Enhance transparency allows you to modify any part of your design using the Enhance Photo Tool, just as if it was a photo. For example you can draw a shape over any part of your design, apply enhance transparency to it and then adjust the brightness of just the area of your design which is covered by the shape.

Applying Enhance transparency

To apply enhance transparency:

Draw or select the shape to which you want to apply the enhance transparency effect.
Go into the Transparency Tool and select "Enhance" from the transparency blend mode list on the InfoBar.
The shape seems to have disappeared from your page! That's because it will only apply enhancements to objects underneath it, and you've yet to specify the enhancements it will apply. The object should still be selected however.
Switch into the Photo Enhance Tool. Turn up the brightness using the control on the InfoBar. Now you can see that the area covered by your shape is brightened compared to the area outside the shape.
You can adjust brightness, contrast, saturation, temperature and hue.
Move your shape around, or transform it and it always applies the photo enhancement(s) to the area underneath the shape.

Normally you'll also want to apply some feathering to the shape using the Feather Tool, to soften the edges of your shape and blend it into your design.