The Transparency property allows to control the transparency of drawing entities. You can set the transparency for a selection of entities or for all entities on the same layer. The default transparency for new entities is controlled by the CETRANSPARENCY system variable. The default transparency for Hatches and Gradient Fills is controlled by the HPTRANSPARENCY system variable.
Transparency can be used to enhance the display of your drawings, e.g. to de-emphasize less important details or entities that are used for reference only.
Transparencies will only be printed if the Plot Transparencies option is checked on the Print or Page Setup dialog boxes.
The options to set the Transparency are:
ByLayer - apply the value of the transparency property of the layer.
ByBlock - the transparency value is controlled by block.
Value - values between 0 (fully opaque) and 90 are accepted.
The transparency level is limited to 90 % to avoid confusion with layers that are frozen or turned off.