What is the principal difference between tazyīn and tashwīh?

Purposes of Simile: Possibility, Condition, Degree, Beautification, Disfigurement and Reversal

• Beautification identifies an unknown quality and disfigurement only measures degree
• Both principally lower the rank of the comparison term
• Beautification evokes admiration, whereas disfigurement evokes aversion
• Beautification omits the marker, while disfigurement always states it