I remember as a kid, making sun prints on specially treated paper. I'd put a leaf or other object on the paper and let the sun print the image onto the paper. In a photography class I used the same process but with a film negative and printed the image in values of blue.
I purchased treated fabrics online from blueprintsonfabric.com . This is a silk scarf.
I chose to use clear acetate for printing a design. Underneath is a piece of kraft paper cut to the size of the scarf. I chose a spiral rubber stamp and used black acrylic paint. Since the printing process is imprecise, I was not too worried about a perfect layout.
Here the printed acetate is over the chemically treated scarf and positioned in the sun. I wanted a medium blue so I timed the exposure for 6 1/2 minutes. After being rinsed in water the color was set with hydrogen peroxide, rinsed clear and allowed to dry. Except for the time in the sun, all work with the fabric must be done in a dimly (almost dark) room. Click here to read detailed instructions.
I would say the most difficult part of the process was coming up with a design. If you need ideas, Google cyanotype prints images for lots of ideas.
This is an example of a sun print on cotton fabric exposed for 10 minutes. It is much bolder in color.
What do you think? Would you give it a try?