Solar Printing Science Activity

In this solar printing activity, we’ll learn how the sun can cause chemical reactions. I love to blend science with another study–like art or history. If you’re planning a solar system study, a solar energy study, a study of UV light, a solar printing activity is a perfect pairing!

You’ll just need:

Solar Print Paper
objects such as craft items like chenille sticks, foam or wood cut-outs, beads and treasures found on a nature hike- feathers, rocks, flowers, sticks–anything that might make an interesting design for your solar prints
sunlight
water – The solar print paper we used had instructions to rinse the designs in water AFTER being exposed to the sunlight to set the print and prevent it from fading over time.
towel

Creating Your Solar Prints

Follow the handling instructions on your solar print paper. Be sure you keep it out of bright light until the design is laid out on the paper you are ready to take them outside to make your solar prints.

I like using these foil pans from the dollar store for projects like this. These pans made it easy to transport the sun print paper when moving outdoors into the sun.

If you want to create larger solar prints, flip two or more pieces of the solar print paper over and tape them together on the backside. Carefully flip and use the larger canvas to make solar prints.

Place the objects on a a piece of the solar prints 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.

solar prints happens quickly when put out in the sun

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 un-reacted 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 prints after they are rinsed in water and left to dry

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