Use whatever water based medium you have to add very watered down brownish color to some parts of the window. Just a hint of the brown tone that should go into creases - this adds more of an antiqued look. I used brown Distress ink - I swiped my craft mat with it and then picked it up with a water brush, but I think that watercolors should work nicely as well. And that's it - my windows were ready.
I wanted to try a bit of a different look for another project, so I tried to swipe some brown acrylic paint over my window and I got this lovely window. It might also need a bit of shading to make it look more of an old wood, but this dark look works just as well as the white one.
Links to cutting files:
If you need any other format, write me and I will try to add it as well.
Hope you enjoyed this tutorial and if so, please let me know when you have made some projects using my cutting files - I love to see creativity spread :)