![This image has an empty alt attribute; its file name is transparent-rectengle.png](http://www.gemmameulendijks.nl/wp-content/uploads/2019/09/transparent-rectengle.png)
Color changing experiments on different fabrics: silk and Batist.
We will work furthermore on the silk fabric and with the aubergine-like color.
This color appears when you bathe the exposed (blue) cyanotype in diluted nitric acid, water the fabric for a while, then bleach it in Soda, water it again for about 10 min, and final step is to bathe the fabric in gallic acid.