Stem Learning

The Magic of Primary Pigments


It’s an interesting fact. The primary colours of pigment namely: cyan, magenta, and yellow can be blended to make many other colours out of it. Demonstrating these colours using traditional markers will not give correct results, as they are only close approximations and not actual colours. However, using printer ink will definitely create the best possible results.

An experiment below demonstrates the true colours of the rainbow that children lay their hands on at home. It is a very easy process for any student to follow.

What are the requirements:

  1. Yellow, magenta, and cyan inkjet printer inks in bottles
  2. Empty or refillable markers
  3. Plastic syringes with long needles
  4. Small clear plastic cups
  5. Several sheets of white paper
  6. Pencil

Steps to Assemble

Each marker pen consists of a barrel, nib, foam cylinder, endcap, and regular pen cap. First, place the nib into the barrel, and then insert the foam cylinder. You can use a regular pen to push the foam into the nib.

Open the cyan, magenta, and yellow ink bottles. Use a long needle and syringe to extract approximately 2-3 ml of ink from the yellow bottle first. Remember you will need one syringe for each ink colour respectively. Then 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 will now see the ink moving through the foam via capillary action.

As the ink reaches the nib, just test the marker to ensure if the pen works properly. In case if it doesn’t work, then add another ml of ink, wait for a while, and see again. If the pen works, then press the end cap onto the barrel of the marker to close it. Repeat the same process for filling magenta and cyan markers.

Make A Blue Marker: Add 2 ml of magenta ink and 2 ml of cyan ink into a small plastic cup and mix it together. Pull the mixture into a new syringe and inject it into a blank marker. Once done, wash the syringes and needles with plenty of water.

How To Execute

With the use of a pencil, draw two circles that overlap each other on a blank piece of paper. Just like the Venn diagram style. Use the yellow marker to colour one circle in completely. Colour the second circle with the blue marker, and not the cyan marker. Look at the overlap section. It gives the colour that was expected.

Now again draw three overlapping circles, also like a Venn diagram. And use yellow, magenta, and cyan markers to fill all three circles, including the areas that overlap. Start with the yellow marker first. Fill each circle completely with colour. Now observe the colour where cyan and yellow overlap, where magenta and cyan overlap, and where yellow and magenta overlap. Finally, observe the colour when all three inks overlap.

Make new markers by mixing different amounts of ink colours in small clean cups. To test the mix of colours, place a few drops in water. You can use this method to make any colour marker you would wish to. If you want to make either a red, green, orange, or pink marker, and not sure which inks to use to produce the colour, then just look at your Venn diagram for the solution.

Now, try varying the quantity of ink from each bottle. Experiment to see if you can make all the colours of the rainbow. It is better advised to do all your ink mixing first, then when you are satisfied with your colours, inject the results into different blank markers.

The Results

Whenever we draw with a marker, it usually means adding colour to the page, but it is actually the reverse. In reality, adding ink is usually removing the colour. In fact, pigments and inks absorb some hues and transmit other hues. Blue ink absorbs every colour but blue. Likewise, green ink absorbs every colour but green. To print a picture of a colourful scene, a printer might need thousands of different inks to make all the colours.

Luckily there is a simpler way that exists. Mix different inks together so that the paper reflects just the colours we want. The question here is how to add pigments together to remove colours? It works a lot like sculpting and it only takes a few specific ink colours.

Imagine that you want to show a green spot on a piece of white paper in sunlight. It is a known fact that sunlight contains the entire spectrum of light, and hence, you already have green light hitting the paper from those rays.

Systematic Approach

Green is in the middle of the spectrum. First, get rid of all the light in the red to yellow range and then find out which ink does that. It may be noted that cyan blocks the red-yellow light, thereby only letting light in the blue to green part of the spectrum.

The yellow ink absorbs light from the other end of the spectrum, allowing red to green light to pass through. If we put a layer of cyan and a layer of yellow below, the only colour that will be able to make it through both pigments is green. You have essentially sculpted the light, removing all the colours from the white light that you did not want.

Likewise, use other pigment pairs to make red and blue. It may be noted that only red can get through magenta and yellow, and only blue can get through cyan and magenta. No colour can get through all the three.

Investigate Colours

It has been learned in elementary school that blue and yellow when mixed together become green. But in this experiment, it is found that green is produced only when yellow and cyan are mixed.

To investigate such misconception becomes a great way to engage the learners. First, take the blue marker drawing on white paper, and then colour the yellow marker next to it, but avoid overlapping. What colour will appear when the blue overlaps the yellow? Yellow and blue when overlapped, gives out black colour and not green.

What if you want orange? Orange is in between red and yellow. To get orange, all the red light from the white light is needed. And only some part of the green light, and none of the blue light. Pure yellow ink will block all the blue light and hence we use it. When magenta ink is diluted or only covers half the surface, it will block only some of the green light. So, if we use pure yellow and dilute magenta, then we can make orange ink. In the same manner, other colour inks can be generated by experimenting with different amounts of yellow, magenta, and cyan inks.