Thursday, 25 July 2013

Swan (2)

This is not the swan painting I was writing about the other day. That one is still not dry!! I was beginning to think I had made a new scientific discovery - the eternally wet paint - but today I think not, as there is some sign that it is tacking up. At last.

I am still experimenting with my swan techniques. Basically, the water is thin and transparent - some of the colour you can see is the cadmium orange under painting showing through the translucent top layers. I used mainly olive green and black, with some Cerulean blue. The swan is much more impasto. I used blue, white, yellow and applied the paint thickly with a bristle brush and cotton buds.

Having asked previously how oil paint dries, I have been able to find out thanks to the Winsor & Newton resource pages - although even they required me to consult a dictionary 4 or 5 times. Look away now if you're not interested.... 

Stage 1: oxidisation: the oil in the paint absorbs oxygen from the air. The oxygen attacks the hydrocarbons in the oils and produces free radicals. 
Stage 2: free radicals are highly reactive due to the presence of an unpaired electron. They start to form compounds (polymerise), a process completed by the free-wheeling electrons pairing up and forming bonds. At this point, the painting will feel dry to the touch.  
Stage 3: these polymer bonds start to cross-link into chains. The chains form a strong, stable molecular network. This process continues ages after the paint feels dry, hence you are not supposed to varnish a painting for a long time after it is finished.

So, my endlessly wet swan painting is even as we speak to each other hosting a speed dating session for unpaired electrons... I look at it with a new respect.


No comments:

Post a Comment