Here’s a description from About.com:

(4) PARTICIPIAL ADJECTIVES, which are either pure participles used to describe, or participles which have lost all verbal force and have no function except to express quality. Examples are,——

Pure participial adjectives: "The healing power of the Messiah," "The shattering sway of one strong arm," "trailing clouds," "The shattered squares have opened into line," "It came on like the rolling simoom," "God tempers the wind to the shorn lamb. "

Faded participial adjectives: "Sleep is a blessed thing;" "One is hungry, and another is drunken;" "under the fitting drapery of the jagged and trailing clouds;" "The clearness and quickness are amazing;" "an aged man;" "a charming sight. "

A PPA (Pure participial adjective) is a participial adjective that retains some force of a verb while acting as an adjective. An FPA (Faded participial adjective) has lost that verbal power.

I must agree the concept is confusing. Let’s examine some of About.com examples cited before:

"The healing power of the Messiah" means the power of the Messiah that heals. ‘Healing’ therefore is not only acting as an adjective modifying the noun ‘power’ but it has the force of its verbal origin ‘heal’. It’s a healing power, one that heals. It’s a PPA.

"Trailing clouds" means clouds that trail. There’re trailing clouds, clouds that trail others. It’s a PPA.

"A charming sight" is a beautiful, pleasing and attractive sight. It’s not used as if the sight could charm anybody. It’ an FPA.

"Sleep is a blessed thing" means sleep could be a holy, sacred and happy event. Although ‘blessed’ comes from ‘bless’, it does not convey its verbal meaning, it describes the quality of sleep only. It’s considered a FPA.

Similar to About.com’s example, ‘fitting’ in It’s a fitting tale is an FPA.

In it’s an enpowering experience,’enpowering’is a PPA as it not only describes the experience, it conveys the force of the verb ‘empower’.