Puzzle 525: Artist's Block 10

As much as I enjoy posting 31x45 puzzles to celebrate milestones (because multiples of 25 are clearly milestones), I'm running out of things to say about them. Hopefully I'll have more to say about my next 31x45 puzzle. :)

Well, I guess I'll say this, since some people seem not to notice when I try to say it unobtrusively in a prefix to the comment form: do not leave a comment claiming a puzzle has multiple solutions unless you can either explain why in a manner that doesn't entirely spoil the puzzle for future readers, or accompany said comment with an e-mail explaining the ambiguity even more uncertainly. While I have made mistakes before when I am overly confident in my own logic, this particular puzzle was test-solved by two individuals who would have undoubtedly noticed such an error. Additionally, please don't spoil what results from shading in the areas with black dots; I would prefer to discuss that via e-mail.

On a completely unrelated note, Sudoku fans may be interested in this Advent calendar David Millar's been working on.

Rules of Artist's Block
(click to enlarge)