Setting the layer transparency
Each layer uses a transparency value from 0 to 90, where zero is no transparency (regular visibility) and 90 is the most transparency (almost invisible).
By default, each layer is assigned zero transparency. If you want a different transparency assigned to a layer, you can easily change it using the Explorer.
To change the transparency assigned to one or more layers
1 Do one of the following to choose Explore Layers ():
On the ribbon, choose Home > Explore Layers (in Layers) or choose Tools > Layers (in Explorer).
On the menu, choose Format > Explore Layers or choose Tools > Explorer > Explore Layers.
On the Explorer toolbar, click the Explore Layers tool.
Type explayers and then press Enter.
2 Click in the Transparency column for the layer you want to change.
3 Enter a new value for the transparency, then press Enter.