Food Waste Pigment

Designers and artists are working a lot with colour. This can be digital, but also in the form of ink. Colour and printing have almost become something normal. You press the print button, and a beautiful, coloured sheet comes out of the printer, but how the colours are made we are often not concerned with.

With her graduation project, The Colour of Waste, Sara van Laerhoven wanted to go back to basics and show how special and beautiful colour can be and that it can be natural. She made her process visual to inspire and motivate others to try it themselves.

By using material research, she found a way to make a natural alternative to synthetic inks to use in graphic workshops. This alternative is made from food waste. In this case from coffee grounds, avocado seeds, red cabbages and orange peels.

A lake pigment is made by transforming a soluble dye into an insoluble pigment. This is done by combining a dye with an inert binder (metallic salt) to make the dye insoluble in water. First, extract dye from the food waste by infusing it into a liquid. Combine the dye with a metallic salt. Sara used alum and washing soda for an alkali. Once the alkali is added the alum becomes solid again, and the colour will stick to the alum. When this is filtered out of the remaining dye solution, dried and ground. What is left is the pigment.

Pigments have some advantages over dyes. The pigments are meant to be long-lasting and durable. Lake pigments can be applied widely by mixing it with different binders, for example printing, painting, and colouring various materials such as textiles, paper, and wood. But you can also use it for making pastels and crayons.