Solar Printing Science Activity -

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When I think of summer, I think of sunshine. Today, we’ll learn how the sun can cause chemical reactions in this solar printing science activity. You’ll just need:

Solar Print Paper
objects such as flowers, sticks, keys, feathers, anything that might make an interesting print
sunlight
water
towel

Creating Your Solar Print

Follow the handling instructions on your solar print paper. Be sure you keep it out of bright light until you are ready to print. Place the objects on a piece of paper and then place the paper in sunlight for 1-2 minutes.

The solar printing is finished when the exposed areas of the paper turn white. (The area under your objects should still be blue, since the sun didn’t hit there.) Take the paper out of the sunlight and remove the objects. Run water over the paper for a couple minutes. Then, lay the wet paper on a towel to dry.

Related post: Solar Magnification Experiment

You should start to notice the white, sun-exposed areas turn blue and the blue shaded areas turn white. This is the final stage of the reaction.

How Solar Printing Works

Solar Print Paper produces prints by a process called cyanotyping. Cyanotyping involves treating paper with a solution of potassium ferricyanide and ferric ammonium citrate. The solar printing paper you buy has already been treated.

When the treated paper is exposed to sunlight, the sunlight reacts with the iron on the paper. This starts a chain reaction which causes ferric ferrocyanide, or the pigment Prussian Blue, to form.

Rinsing the paper washes the unreacted iron away. As the paper dries, the Prussian Blue color is revealed.

Try Solar Printing Yourself

Many school supply stores and art supply stores have solar printing paper. I bought ours at a local museum gift shop. Like with anything else, you can also find solar print paper on Amazon, too.

Get creative with objects. In the picture above, we used flowers and leaves from our yard in one print and sunscreen in the other.

Solar printing can be done on fabric, as well as paper. This is an old technique that is a true artform. To see some beautiful cyanotype prints, check out this Cyanotype Pinterest Board.