Your heraldic can be engraved in two different methods, to read or seal.

When it is an engraving to read, the symbols are not reversed and the currency can be read with a magnifying glass.
If engraving is “to seal” this one is made in hollow and wrong side, so that the wax print is embossed patterns and right side.

Example of an engraving to read (Summary of life of a pharmacist).

Example of an engraving to seal with \"ecu, heaume, tenants and listel\".