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Truly Primary Pigments

Science Snack
Truly Primary Pigments
Make your own mix-n-match markers to produce a rainbow of colors.
Truly Primary Pigments
Make your own mix-n-match markers to produce a rainbow of colors.

The primary colors of pigment are cyan, magenta, and yellow, which can be mixed to make many other colors, but demonstrating this can be difficult if you want to use markers. Traditional markers labeled cyan, magenta, or yellow often are not actually those colors, but close approximations. Using printer ink will give you the best results.

Tools and Materials
  • Inkjet printer ink, sold in bottles for bulk refilling, in the following colors: yellow, magenta and cyan (we’ve had good luck with the BCH brand sold online)
  • Six or more empty or refillable markers (such as a Crayola refillable marker kit or empty markers made by Molotow)
  • Several plastic syringes with long needles, at least one per ink color (these usually come with bulk inkjet refills)
  • Small (approximately 10-milliliter) clear plastic cups
  • Several sheets of white paper
  • Pencil (not shown)
  1. Each marker consists of a barrel, a nib, a foam cylinder, endcap, and regular pen cap. Place the nib into the barrel and then insert the foam cylinder. Use a regular pen to push the foam into the nib.
  2. Open the cyan, magenta, and yellow ink bottles. (Note: If you purchased a refillable marker kit such as the one made by Crayola, discard the ink that comes with the kit. Printer ink is much purer in color. If you purchased a printer refill kit, set aside the bottle of black ink for another use.)
  3. Using a long needle and syringe, extract 2-3 mL of ink from the yellow bottle. (You’ll need at least one syringe for each ink color. Keep the syringes separate so that the ink colors remain pure.)
  4. Press the needle just below the surface of the foam in the marker and push the plunger down slowly, injecting the ink into the foam. You’ll see the ink move through the foam via capillary action.
  5. When the ink reaches the nib (this usually takes a few minutes), test the marker to be sure the pen works. If it doesn’t work, add another milliliter of ink, wait a bit, and try again. If the pen works, press the end cap onto the barrel of the marker to close it off. You should hear an audible click.
  6. Repeat the process on a new marker with magenta, then cyan.
  7. Make a blue marker: put 2 mL of magenta ink into a small plastic cup, and add 2 mL of cyan ink to the cup. Mix together. Pull that into a syringe and inject that into a new blank marker.
  8. When you’re done, wash out the syringes and needles with plenty of water.
To Do and Notice

On a blank piece of paper, use the pencil to draw two circles that overlap, Venn diagram style. Use your yellow marker to color one circle in completely. Color in the other circle with the blue marker (not the cyan marker). Look at the overlap. Is that the color you expected to see?

Now use your pencil to draw three overlapping circles, also like a Venn diagram. Use the yellow, magenta, and cyan markers to color in each of the circles, including the areas that overlap (starting with the yellow). Try to fill each circle completely with color. What color do you see where cyan and yellow overlap? What color do you see where magenta and cyan overlap? What color do you see where yellow and magenta overlap? Finally, what color do you see when all three inks overlap?

Make new markers by mixing different amounts of your ink colors in small clean cups. To test your mix of colors, place a few drops in water or write on an overhead transparency designed for inkjet printers.

You can use these methods to make any color marker you’d like. How would you make a red marker? How about one that’s green or orange or pink? If you’re not sure which inks to use to produce the color you want, look at your Venn diagram.

Try varying the quantity of ink from each bottle. Experiment to see if you can make all the colors of the rainbow. It’s best to do all of your ink mixing first, then when you are satisfied with your colors, inject the results into different blank markers.

What's Going On?

Hue is an attribute of color that corresponds to a position on the visible light spectrum. Color is what we perceive. It may be comprised of a mixture of hues and also takes into account brightness.

When you draw with a marker, we usually think of this as adding color to the page, but it is actually the reverse. Adding ink is usually removing color. How? Pigments and inks absorb (turn into heat) some hues and transmit (reflect) other hues. “Blue” ink absorbs every color but blue. “Green” ink absorbs every color but green. This works fine, but it can be inconvenient. To print a picture of a colorful scene, a printer might need thousands of different inks to make all the colors.

Luckily, a simpler way exists, which is to mix different inks together so the paper reflects just the colors we want. But how do you add pigments together in order to remove colors? It works a lot like sculpting and it only takes a few specific ink colors. Imagine you want to show a green spot on a piece of white paper in sunlight. Sunlight contains the entire spectrum of light, so you already have green light hitting the paper. The problem is that you also have red, yellow, chartreuse and many, many more hues hitting the paper so you can’t see the green. So, you need a way to get rid of (subtract) the colors you don’t want.

Let’s be systematic. Green is in the middle of the spectrum. First, let’s get rid of all the light in the red to yellow range. Is there an ink that does that? Pure cyan blocks red-yellow light, only letting light in the blue to green part of the spectrum through.

Yellow ink absorbs light from the other end of the spectrum, allowing red to green light to pass through, so If we put a layer of cyan down and a layer of yellow down, the only color that will be able to make it through both pigments is green. Voila! You have essentially sculpted the light, removing all the colors from the white light that you didn’t want.

By using other pigment pairs, you can also make red and blue. Only red can get through magenta and yellow, and only blue can get through cyan and magenta. No color can get through all three.

Going Further

You may have learned in elementary school that blue and yellow mix together to make green. But in this activity, you were only able to produce green when you mixed yellow and cyan.

Investigating this misconception is a great way to engage learners. First, show that the blue marker makes blue ink by drawing with it on white paper. Then color next to it with the yellow marker, but don’t let them overlap. What color will appear when the blue overlaps the yellow? Overlapping them shows that yellow and blue make black and not green. What two colors make green when they overlap?

What if you want orange? Orange is in between red and yellow. We want all the red light from the white light, but only part of the green light, and none of the blue light. Pure yellow ink will block all the blue light so we’ll use it. If we use dilute (or only cover half the surface) with magenta ink, it will block only some of the green light. So, if we use pure yellow and dilute magenta we should be able to make orange ink. Other inks can be generated by combining different amounts of yellow, magenta, and cyan inks.