Enchanting (ability) writing

Salve sodales!
One of my player want to use enchanting writing, but my question may be applied to all those abilities like drawing that requires a long time to prepare (like cerimonial spells).
In this case(for example in case of a paint), how do you handle the effect? It work only agains those who see the creation of the paint or those wo will see it when it's finished? and for how long the magic perdure in the second case?
Thanks in advance!

Personally I would say Enchanting Writing only pertains to the written word. For paintings, one should require Enchanting Artistry which might then allow for specialisation in any one of the several art forms of the age (Painting, Sculpture, Woodcarving, Tapestry weaving, etc).

As for the duration of effect, that is the same with invested effects as it is with spells. If the effect Duration is momentary then it lasts only as long as the target is viewing the artwork, if sun then it will endure well after he views the artwork. Its up to the SG and player to work out those aspects.

Of course this is all serf's parma and may be explicitly laid out in the RAW but I am speaking from mere opinion here.