(example from the makers of Sunprints)
Basic instructions are on the back of the box - more Tips and Tricks
1. Thicker, more opaque specimens produce a whiter image against the blue background. However, some thin slightly translucent specimens can produce beautifully shaded, very delicate images. Three-dimensional objects or any part of the specimen which casts a shadow may create a middle blue tone (for the shaded area) in the final Sunprint.
2. Minimize exposure of the paper to sunlight until you are ready to make your Sunprint. For example: leave the paper in the black plastic envelope until you get your specimen ready. Place the specimen on the Sunprint paper in a darkened area (such as inside a cardboard box or under your sweater). Then quickly place your paper and specimen on a flat surface exposed to direct sunlight.
3. Five minutes is a suggested exposure time. Often a shorter period will produce better results. Observe the paper during the exposure time. You will notice that the blue color fades from the areas exposed to sunlight. When the fading seems to stop, the paper has had enough exposure. Its not necessary to wait until the exposed area has turned completely white. Experiment with different exposure times. More sunlight, long exposure times will not necessarily produce a better finished productin fact, if your specimen is thin and somewhat translucent, a longer exposure time can cause the final print to have less contrastin other words, the image will appear less white, bluer, and seem to fade into the background blue.
4. Develop the paper in water which is not exposed to direct sunlight. While the Sunprint is developing in the water, it can still be affected by sunlight. What the sunlight touches will be blue.
Monitor your water bath. When the water starts to discolor, get fresh water.
5. Allow the Sunprint to air dry overnight in a place that is protected from sunlight.
To see more examples of what you can do with Sunprints, check out the cyanotype
art at ASLstuff