Rebecca
SGF, Supreme Grumble Framer
I suprised Buddy when I said that wheat starch paste hinges, mends and backings are not always reversible. In case I suprised anyone else, he said I could post my reply to him.
I would be interested in other people's thoughts on the subject too.
In theory, wheat starch paste/Japanese paper hinges, mends and backings are always reversible. In practice, there are cases when they are not reversible. Very fragile, or soft, short fibered papers, very delicate papers, degraded papers etc. may not be able to withstand the stresses involved in removal. The paste has to be humidified or moistened to soften it sufficiently for removal of the paper. This can, in some cases, weaken the paper enough that hinge/mend or backing removal will result in fiber loss, delamination, skinning etc. Enzymes can be used to digest the paste, but that can cause its own set of problems.
Sometimes it's best just to leave the Japanese paper/paste on, knowing that it will have good aging properites.
Sometimes I will back a very fragile paper with Japanese tissue and wheat starch paste, knowing that it will probably be impossible to remove that backing in the future. In cases like this it is doubly important to use use the best quality materials, that impose themselves as little as possible on the original. So I would use a very thin tissue, and a thin paste. That way the paper is strengthened, but still remains flexible - as much like the original sheet of paper as possible.
Another point in the concept of reversibility is the "Ideal" vs the "Real". Even in the best situation some of the paste is bound to be absorbed by the paper. But this rarely makes a difference is the appearance or aging of the piece. Of course some papers are totally water reactive, and shouldn't be paste hinged, mended etc.
Conservators always strive for the ideal of reversibility, but often it's an impossible ideal. That doesn't mean we throw the idea out, just that we realize there are practical limitations.
Japanese paper and wheat starch hinges are still, in almost every case, the best thing to use. I've mentioned using pressure sensitive tissue made from Lascaux HV 360 acrylic emulsion and Japanese paper as a substitute when a piece is very water sensitive, but if anyone wants, I can post it again.
It's good to question accepted practices, and be open to new ideas. Conservators change their minds all the time according current ethical/philosophical interpretations of "reversibility", the balance between stability and aesthetics (to clean or not to clean), and new information about materials and techniques that conservators and conservation scientists come up with. And there is plenty of disagreement within the field. Look at all the fighting going on over cleaning Michelangelo's David! http://www.guardian.co.uk/italy/story/0,12576,998966,00.html
Rebecca
I would be interested in other people's thoughts on the subject too.
In theory, wheat starch paste/Japanese paper hinges, mends and backings are always reversible. In practice, there are cases when they are not reversible. Very fragile, or soft, short fibered papers, very delicate papers, degraded papers etc. may not be able to withstand the stresses involved in removal. The paste has to be humidified or moistened to soften it sufficiently for removal of the paper. This can, in some cases, weaken the paper enough that hinge/mend or backing removal will result in fiber loss, delamination, skinning etc. Enzymes can be used to digest the paste, but that can cause its own set of problems.
Sometimes it's best just to leave the Japanese paper/paste on, knowing that it will have good aging properites.
Sometimes I will back a very fragile paper with Japanese tissue and wheat starch paste, knowing that it will probably be impossible to remove that backing in the future. In cases like this it is doubly important to use use the best quality materials, that impose themselves as little as possible on the original. So I would use a very thin tissue, and a thin paste. That way the paper is strengthened, but still remains flexible - as much like the original sheet of paper as possible.
Another point in the concept of reversibility is the "Ideal" vs the "Real". Even in the best situation some of the paste is bound to be absorbed by the paper. But this rarely makes a difference is the appearance or aging of the piece. Of course some papers are totally water reactive, and shouldn't be paste hinged, mended etc.
Conservators always strive for the ideal of reversibility, but often it's an impossible ideal. That doesn't mean we throw the idea out, just that we realize there are practical limitations.
Japanese paper and wheat starch hinges are still, in almost every case, the best thing to use. I've mentioned using pressure sensitive tissue made from Lascaux HV 360 acrylic emulsion and Japanese paper as a substitute when a piece is very water sensitive, but if anyone wants, I can post it again.
It's good to question accepted practices, and be open to new ideas. Conservators change their minds all the time according current ethical/philosophical interpretations of "reversibility", the balance between stability and aesthetics (to clean or not to clean), and new information about materials and techniques that conservators and conservation scientists come up with. And there is plenty of disagreement within the field. Look at all the fighting going on over cleaning Michelangelo's David! http://www.guardian.co.uk/italy/story/0,12576,998966,00.html
Rebecca
