Making decorative art, one boy put in identical copy (9)

I believe the answer is:
cloisonne
'making decorative art' is the definition.
I can't tell whether this definition defines the answer.
'one boy put in identical copy' is the wordplay.
'one' becomes 'i' (Roman numeral).
'boy' becomes 'son' (male child).
'put in' is an insertion indicator.
'identical copy' becomes 'clone' (I've seen this before).
'i'+'son'='ison'
'ison' put inside 'clone' is 'CLOISONNE'.
Can you help me to learn more?
(Other definitions for cloisonne that I've seen before include "Enamel work" , "enamelware" , "Panelled enamelwork" , "Sort of design" .)
