I still am dubious about bleaching paper, and I really have to do more research into it to become more informed, but as a first impression – a technique that can significantly alter the colour of paper so quickly can’t be good. However, some people still use this technique and it was widely used in the past, so learning about it is going to be of some use. (My guilty wish now, is to pick up discoloured second hand prints and turn them pearly white again!)
We started by picking out a page from the same book as the last session and experimenting with spot bleaching on the vacuum table. I had chosen to work on an area of particularly bad foxing.
The bleaches used were EDTA (Ethylenediaminetetraacetic) a chelating agent, Calcium Hypochloride, and Hydrogen Peroxide, each applied with a brush as a droplet onto the fox mark.
Notice the haloing around each fox mark – this I think could be reduced by washing the page before bleaching. Calcium Hypochloride was the most effective at removing the stain, but also removed the colouration in the paper, making the mark more obvious. Multiple applications of EDTA would be more effective.
As Calcium Hypochloride gave the most contrast, it was chosen as the bath in which a page would be immersed.
The lighting in these photos isn’t great, I’ll upload some better ones on Weds.
And this is where my camera decided to run out of battery. I’ll finish the post when I can take some more pictures of the pages after treatment.