Diazo

Diazo is like magic paper that changes color when it is exposed to light. Just like when you go outside and your skin changes color in the sun, diazo paper changes color when it is exposed to light too!

Diazo paper is made by coating regular paper with a special chemical called diazonium salt. This magical chemical is sensitive to light, meaning that when it is exposed to light, it starts to change.

When you draw or write on diazo paper with a special pen called a diazo pen, the ink reacts with the diazonium salt. This makes the paper change color where the pen touched it.

But here's the cool part: if you take the diazo paper and put it in a machine called a diazo copier, the machine will shine a special light on the paper and make it change color all over again! This allows you to make copies of your drawings or writing, just like making copies of a regular piece of paper.

Diazo is used in lots of different ways, like making copies of blueprints for buildings or engineering designs, or even in photography! It's like a secret magic trick hidden in plain sight!