I've just finished scanning and stitching together 49 marbled and dyed papers for my personal texture library.  A few samples are included in this post.  

Both processes tread a tightrope between control and random effects.  Marbling is a fluid process that happens to be frozen when the paper hits the water.  The dying samples were made by soaking folded paper and dipping edges and corners in fabric dye.  Japanese Mulberry paper captures the patterns and soaks the dye beautifully.

Both methods encourage "happy accidents" and require comfort with ambiguity.   In other words you have to be okay with whatever happens.  These are likely to appear as elements in future illustrations.

See more artwork from Jason Jaspersen at jjjaspersen.com, and on social networks such as Facebook, Twitter, and LinkedIn.