I generally do not keep separate Art Journals for each medium. I usually do paintings, collage and everything else in one journal.
This year I'm doing something different. I created a Watercolor Art Journal which I posted about a few days ago.
Now, I've taken an inexpensive small Piccadilly journal (about 5" x 8") and decided to do Simple Art Pieces in its' pages. Maybe collage art or paintings. Here is the first page that I worked on. I may add some art stamps to the page.