1350 – 1600 AD
In the world of art, there was an explosion of new ideas and some pretty cool new paints – oil paints!
For the first time, artists were creating entire pictures with these paints and mixing pigments – that’s the coloured particles – with different types of oils.
The oil molecules are like long chains and when they’re exposed to the air, these molecules all join together and get stiffer and harder – a process called polymerisation.
Oxygen reacts with the molecules of paint and, when the process finishes, the paint ends up being glossy and really hard! This process isn’t done overnight though – it can take weeks or even months!
But this slowness was great for Renaissance artists as it allowed them to create more realistic scenes. They could keep adding other colours and work at the paint for much longer than was possible before!
The types of paints used in art has changed over the years depending on what was around, what could be traded and what was being invented.
Chemists can use the knowledge we have to do some pretty cool detective work…
The picture above is called The Master of the Mornauer Portrait. It looks fairly normal, right? Except it’s the blue background that’s got art experts scratching their heads.
They thought it was a bit unusual for this time period and so took tiny grains of the paint and used very powerful microscopes to look at them up close – up to a thousand times their original size!
The tiny grains of paint were added to another chemical which reacts with some types of blue paint but not with others. The solution turned black, which meant the chemists could tell it was Prussian Blue.
Now we know that Prussian Blue wasn’t commonly used five hundred years ago – so chemists were able to prove that this painting didn’t start off like this!
They were even able to pin down where the changes were made by looking at tiny differences in the oils, as some oils were only used in certain places and contain clues as to where that may have been!
They discovered the blue later was added on top of the varnish, which is usually the very top coat on a painting.
But why would someone go to all the trouble of adding another layer?
Well, because blue backgrounds are kind of rare in old paintings, a later owner may have tried to make it look more valuable than it actually was!
The more we know about art, the better we can conserve it – and get to solve a few mysteries along the way!
So, let’s go see what we can find in our next period of history – the Baroque era!