Origin framed and oil experiment

Happy how it turned out when framed :) A4 size done with lead pencil on watercolor paper, kinda like the rough feel on that paper.

Painted on a pretty big board, really fun to play around with. One thing that I observed was that the upper part where I used another brand of oils the colors went a bit grayish and weird. Anyone know why? Using linseed oil to mix the oils in.