Skip navigation

Learning about colour synthesis

What it is
Pigmento is a learning experience which allow children aged between 5 and 11 to play with the subtractive synthesis of colour. The technical principle is to video-project coloured light to illuminate a granular material, in this case coarse salt.

How it works

The primary colours are within the borders, so it is possible to mix them into the centre, depending on how much primary colour has been moved. It is called Pigmento because of the link between the hand-made colour and the technological facilities.

Why for children
The traditional learning environment is often a limit. The approach takes inspiration from the “Munarian laboratories” and the Learning Through the Arts programme. The aim is to teach any subject from arts.

Why colours
It is one of the main studying topic in the primary school. Nonetheless there is not so much attention about the interdisciplinary aspects.

Focus is on connecting aesthetic and scientific qualities. Many schools try to keep the budget low, so the material has to be reusable. As it happens physically, there are many more opportunities for making things together. So more children can play at the same time.

The table is round and big enough for several children to play together and get a shared result. This needs to be a continuus process. The surface is divided into two main parts: the primary colours at the borders and their derivatives in the centre. The salt can’t cover more than one part at the same time.

Colour design
The two main colouring techniques are colorato and colorito. The colorito technique may pursue optical synthesis with the subtractive logic because the primaries are cyan, magenta and yellow. The salt has also particular optical qualities. This principle has been accepted as abstract for the National Conference in Colours, which will take place in La Sapienza University in September 2011.


The main tasks are: building the calibration between the webcam and the videoprojector, and programming. Used were Processing and the OpenCV library, Arduino for the LED thresholding and iGlassManager for the manual camera settings. The prototype works under the “colorato” algorithm.

User testing
I spent some time trying it out with three children, aged from 7 to 9. One of them played twice. Even after a few tests I got surprising and useful feedback as a way to create stories

The report is in Italian, but its last chapter show many illustrations of the challenges I confronted.

Any queries or comments to giuseppe[dot]burdo[at]gmail[dot].com or

This interactive table will be shown in several science festivals, as in Venezia and Genova.

Check the pigmento website to know more about: