If you could visit Paris at this period, you’d see loads of artist painting outside for the very first time! Colour chemists had invented stacks of man-made paints, and new technology meant these could be ready mixed-up and stored in handy, squeezy tubes!
Tubes made it super easy to take paint outside. Impressionists loved doing this – they called it painting in ‘plein air’, partly because they wanted to capture the way sunlight made things look cool!
But stand a little bit closer and you can see things look very different…
It’s all just a load of dots!
That’s what makes a painting an Impressionist painting! Rather than swooshing paint around and mixing the colours on the canvas, artists used lots of dabs, dots and lines to create a picture. They also had to be very careful not to let the dabs of each colour squish into the other colours.
There aren’t usually that many different coloured dots but these paintings seem to be full of different shades when you stand further away!
Of course, there’s some clever science behind the effect. It’s all to do with how colours are created, and how our eyes and brains make sense of things.
The colour that something appears to be is all down to the light.
Just think of how different things look by moonlight compared to when you see them in daylight.
When light shines on something, some of the light passes into the object but some of it bounces back. The amount of light that bounces back helps dictate the colour that that object appears to be.
In black paint, all the light energy is being absorbed. Scientists have recently created a substance that absorbs nearly all the light that shines on it – it’s so black, you can hardly see it! At the other extreme, sometimes light energy passes right through an object and out the other side – this makes things look transparent – like a window.
With most paints, some of the light energy is absorbed and some is reflected back to our eyes. Our brains make us see these effects as different colours.
Light from the Sun contains all the colours. The absorbed ones are left behind and only the reflected ones are returned to our eyes.
Brains are brilliant at making sense of the world around us. As well as working out colours, our brains can put together a picture from lots of little pieces of information it receives – like the dots on an Impressionist painting! It’s a bit like when you look at a cloud and see the shape of a rabbit – your brain is always looking for patterns and shapes that it recognises.
The cool thing is that no two molecules will absorb or reflect light in exactly the same way. It’s like they have a fingerprint, which really helps chemists when they’re trying to conserve paintings.
Check out this microscope, called the Energy Dispersive X-Ray Microanalysis and Scanning Electron Microscopy (or EDX SEM for short.)
The EX SEM fires a beam of light into a sample of paint. Scientists are then able to observe information coming back that tells them all sort of things about the make-up of the paint.
It’s basically like looking at the “fingerprint” of the molecules inside the paint.
It’s important that scientists know everything they can about the paint they’re working with. For example, if they find out that the brown contains bitumen, then they’ll know that they mustn’t use heat if they’re trying to fix the painting as bitumen has a habit of melting! That’d definitely ruin the painting!
Chemistry and Art is produced with support from The Royal Society of Chemistry. Click here to find out more