A client commissioned me, as an "extra" at the end of a portrait job, to take pictures of graffiti on their stairs walls. in the flat grey area there is a bird painted (censored).
Setting up flashes and turning off lights were not viable options.
To the question: how can i normalize exposure (and if possibile, but less important, color balance) through the frame in a sort of automated way?
The logic sound pretty clear to me:
- subject can be quickly filled in with content-aware
- get rid of wall texture through blur
- for each pixel there must be an offset which leads to 90% grey
- apply the same "offset mask" to the original layer so that also subject gets the same correction.
Point 1 and 2 are clear and can also be quickly automated: any help with points 3/4 would be amazing!