Cyanotype Test strip Instructions
Knowing how long to expose your cyanotype to the sun can be tricky. When you’ve made several and get the hang of it in combination with different types of weather conditions, you can guess and be good. There isn’t a lot of variation after a certain amount of time, so it’s not ruined if you wait a minute longer. But knowing takes practice. If you’re new to this, it can be helpful to make a test strip and nail down the timing to be more precise.
*Note: You will need a piece of coated, dry paper to make your test strip. The test strip paper must be the same kind of paper you intend to use for your final prints or the results won’t match. Follow the first six steps on the dry method instructions to create your coated paper.
Gather materials: coated piece of paper, pencil/pen, container for rinsing, water, timer, towels.
Mark off a piece of coated paper with sections for minute increments up to about 15. Whichever side you start on, will be the 15 minute mark. Number the sections going backward to 1.
Cover up the strip with something dark like black paper or a piece of cardboard.
Slide the dark paper over to reveal section 15.
Start your timer for 1 minute. I like using the stopwatch on my phone for this. So you can move the paper as each minute passes instead of setting a new 1 minute timer.
Keep exposing 1 minute at a time, pulling the dark paper over after each minute.
Once you’ve exposed all sections, take your print over to a container of cool water and place it inside.
Swish the paper around side to side for a few minutes.
Lay your test strip on a towel. Blot the paper with another towel to remove any excess water.
Leave print to dry.
The intensity of the blue will change over each minute and you can choose the length of time that matches your desired blue.
Example Test Strip
In this test strip, you can see that the depth of blue does not change much after 5 minutes. With this information, you should expose for at least 5 minutes.