Chromatography: Exploring Hidden Colors

It's Color Month here at Apartment Therapy, the perfect time to celebrate all the unsung colors that make up the ubiquitous black marker. Chromatography experiments sound impressive but are super-simple to pull off and are satisfying for geeky and/or artistic kids and/or adults…

"Chromatography (from Greek χρῶμα chroma "color" and γράφειν graphein "to write") is the collective term for a set of laboratory techniques for the separation of mixtures." (Thanks, Wikipedia!) It is used in everything from coffee tasting to perfumery to determining the fat content of different types of cheeses. For our purposes here today, we're going to focus on the "chroma", using water to separate the dye molecules in washable black (or colored) markers. The least dense colors will travel the farthest from the original marker mark, while the most dense color molecules stick closer to home. Fascinating, and beautiful.

  • Annilygreen, her husband, and her toddler created this first gorgeous image, using chromatography paper, washable markers, and just a little water. So clean and modern- they would look fantastic matted & framed. See more on their blog.
  • The 2nd photo is from How To Smile's radial chromatography tutorial. My favorite aspect of this one is that it encourages you to use "all the water soluble black markers you can find laying around". Seeing the difference in pigments from one black marker to the next sounds intriguing.
  • The final image is from DadCanDo's Felt Pen Chromatography project, which utilizes long strips of blotting paper to demonstrate how far each of the pigments travel. As the instructions say, "The experiment can be used as a basis for some interesting discussions about colour and the fact that even dye molecules have different weights (or mass, if you want to go there)... The different dyes used to make up the felt-tip colours are made of molecules of different weights (mass), the water can carry the less heavy dye molecules further up."

There are a lot of other great chromatography projects and discussions around: National Geographic's Science Blog has a slightly more complicated project using eyedroppers and folded coffee filters, the Exploratorium's Black Magic tutorial is simple and cute, and Bird And Little Bird's Kitchen Table Science explores all the pigments that go into colored markers. So fun!

(All images as credited above.)

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