Paper washing and bleaching, vol 2

The second part of my washing and bleaching post is more about the bleaching part. As mentioned in the previous post, this is rarely done in conservation as it is thought to damage the structure of the paper fibres and will continue to disintegrate the object if not denatured properly. As before we were also measuring the experiments as we went to see the difference in paper weights as they were cleaned.

Sodium Dythonite (EDTA), Hydrogen Peroxide, Calcium Hypochlorite

There were three forms of bleaching we used in this session – Sodium Dythonite, Calcium Hypochlorite and Hydrogen Peroxide.

Spot testing the different bleaches

Sodium Dythonite at pH8
Conservators will us Sodium Dythonite to a certain extent, and will often prefer this solution, however it is often not removed totally and can leave a residue in the object. Similarly to this, conservators will often reuse this solution on the same spot many time over in order to remove a stain, however this repetitive use of the solution can be much more damaging than using a stronger one, such as Calcium Hypochlorite, to begin with and ensuring it is removed in full.

20g of Sodium Dythonite into EDTA (unknown amount)
Adjust the pH with Sodium Hydroxide until pH 8 is reached
This required a large amount of Sodium Hydroxide, possibly as the strength of the latter and the amount of EDTA was unknown.

Calcium Hypochlorite at pH9 (bleach of choice)
This solution often has a bad name, though we have been told it does not diserve such a reputation. It is argued that chlorine may be left in the object after de-naturing it (washing through with water). This is chemically suspicious as chlorine is linked to calcium and the molecules are strong and generally stay together. Once the calcium is removed, the chlorine will have nothing to attach to and should come off as a gas.

200ml of 4% Calcium Hypochlorite into 600ml of water
Intial testing of pH showed it at pH10.5
10% Acetic Acid was added to bring the pH down to 9

Hydrogen Peroxide at pH9
When it is used on objects, it will bleach as it drys due to unstable H2O2 molecules, which will release the spare O as a gas, denaturing itself in the process. However a conference in Vienna argued that this did not always occur and peroxide was left in the paper causing continual damage, it is therefore no longer used.

3ml of 3% Hydrogen Peroxide into 23ml of demonised water
The pH is altered using Ammonia to reach pH9
This should bring the amount up to 30ml

We then used each of these bleaches, mostly the Calcium Hypochlorite, and tested methods of cleaning. Everything was done on the vacuum table, having first humidified the object, and thoroughly washing it throughout. We used small amounts on a brush to target small stains such as foxing, and also spraying specific areas by masking the object with melinex.

Calcium Hypochlorite used on a masked out area
Half and half on the same sheet (using bleach of choice)

In the case of immersion, the whole page was put in a bath of Calcium Hypochlorite and then washed in water and left to dry.

Immersion into a bath of 4% Calcium Hypochlorite
Before immersion
After immersion


Making Wheat Starch Paste

This is a post I have been meaning to do for a while, both for me to refer to in the future and for anyone interested, and have finally got my act together after a nudge from Sago On Tuesdays! I hope that I may be able to add to it in the future as I learn new techniques. At the moment I only have three or four to list, but they are good ones that I like.

Paste at the V&A

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The V&A use shofu paste powder for their paste, it is one of the most refined pastes and is a good tackiness and consistency. It is also not necessary to let it stand like with common paste, it can be cooked immediately.

– Mix 27g shofu powder to 200ml water in a beaker and stir together
– Place the beaker on a hot plate on a medium heat
– Stir for about 15 mins or until the liquid starts to go clear and thicker
– Turn up the heat and continue to stir until the paste is thick enough and stays on the stirrer.
– Cover the beaker with a damp cloth and place in a sink of cold water to cool
(have a cup of tea)
– Once cool transfer the now jelly like paste to a clean beaker
– Fill with water until the paste is all cover and recover with a damp cloth
– This can now be left for a few days on the side (not fridge)
– When using it, take how much you need and sieve it three times
– Do not return served past to the beaker

In this case and all cases where paste is cooked on a hot plate, the paste must be on the heat for at least 35 mins and constantly stirred. This is so that the enzymes can open up and create the tackiness.

Paste at Camberwell College of Arts

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Paste at Camberwell is unfortunately the slowest process, but very authentic in terms of how it was made once upon a time. It makes quite a sticky dense paste, with little liquid, which is good for many purposes.

– Mix 1 part paste to 4 parts water and leave to stand for 20minutes
– Poor the mix into the top part of a double boiler (above), and fill the lower part with water
– Set to a high heat and constantly stir until mixture becomes like custard
– Lower the heat and continue to stir until it has been cooked for about 35 mins, it should be clear like silicone
– Leave to cool and then sieve 2/3 times

Paste at the The National Arhives

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The National Archives also use shofu paste because of its good qualities, and unlike anywhere else I have been, they also use a saucier, which removes the need of a stirrer! Their paste is also at 20% concentration, which I find a little too liquid, but it is made for everyone, so is what most people there require.

Using a saucier
– Mix 20g of shofu powder with 100/150ml distiller water (dry/wet)
– Put the mixture in the saucier and set to level 4 (out of 5)
– Allow to cook for 30 mins
– Sieve 2/3 times
– Keep in the fridge when not in use

Using a microwave
– Mix 20g of shofu powder with 150ml of water in a beaker
– Microwave at short intervals as below, stirring in the middle
60s/20s/20s
– Sieve 2/3 times

Paper washing and bleaching, vol 1

Bleaching is a dirty word in conservation, one whispered secretly. However there is no denying that there is something roguishly fun about sticking an old page from a book into a bath of bleach and watching it go from brown to bright white! I can state that the Rev will also be seeing some bleaching treatment in the next couple of weeks, and might then go on the wall!).

This is what we have been doing in the last week with Alan Buchanan, a visiting lecturer of ours, who is very charismatic and great to listen to. We have been working very scientifically and thoroughly, ensuring variables were recorded before starting out, and a control kept.

Preparing the paper for washing
Prior to our various forms of cleaning, it was necessary to record the primary data of the paper, so that we could see the difference once cleaned. We were using pages from the same book, so although they varied slightly in weight, they were very similar on most parts. Each sheet was weighed five times at intervals of 20 seconds, and a mean average taken from those recordings. One sheet was kept as a control and has remained unwashed.

Weighing the paper
The first four pages, ready for cleaning

Washing the paper
Immersion
A simple and straight forward method of cleaning, and one often with satisfactory results as the water will yellow when significant amounts of dirt are removed. Prior to immersion, the page had to be humidified. Immersing a document immediately into water is too much stress for the paper, it needs to be gently introduced to water so that it will accept it more readily. Once humidified we put the page into the water, at about 30 degrees, and left it for 30 minutes. After this, the page came out and was left on the drying rack to dry. In order to flatten it after that, it would need to be humidified again and pressed. Pressing is not something we are doing in our experiments.

Humidification
Ceder humidification chamber
Immersing the page into 30 degrees water
Drying the page on the rack

Float washing
In my opinion, this was the method of washing with the most obvious results as a distinctive residue of dirt left on the blotter. Again, prior to the was, we humidified the page. There are a few methods of float washing including ones where the object is left at an angle and water permanently run underneath it, but Alan assured us that there is no evidence to support one method working better than the other, and in his experience, this was an effective one. In a bath containing two sheets of blotter, water is introduced until it reaches the same level as the blotter, no more. Then the humidified object, recto up is placed onto the blotter. We also left this for 30 minutes. The benefit of this method is that the recto is kept dry, or at least away from the water and relatively untouched, which would be important with fragile media. If the document itself was fragile, it could also be placed on bondina before going on the blotter, which would protect it.

The second page being float washed
The remaining stained blotter

Blotter Washing
The third method of cleaning was the blotter wash, it is an extremely gentle form of washing, should the object have friable media or is delicate in itself. Primarily the first sheet of blotter is lightly wetted, this is a little more needed than for humidification, but not much. At this point both the dry and wet blotter should be weighed. On a clean surface, the dry blotter is placed down, then a sheet of roofing felt (goretex is the more expensive version of the same thing) then the object, recto up, the second sheet of roofing felt, and finally the wet blotter. This should then be covered with a piece of plastic and weighed down to keep the moisture contained. This is then left for an hour or more, as it is a gentle technique and needs time to work. If the object is very delicate, bondina can be used either side of the object. The method works by gravity pulling the water from the wet blotter through to the second, as well as the capillary matting from the roofing felt – this allows vapours through, but not droplets of water. As the second blotter is dry, it will be naturally pulled through to this blotter, via the object, cleaning it in the process. The reason for the object being recto up is so that any matter drawn through the object would show on the verso. Once the hour is up, the blotters are weighed again and there should be a considerable difference in weight.

Wetting the blotter
The cleaning method in action

Washing on the vacuum table
This is not as delicate as the blotter wash, but more so than the other methods. The object must first be humidified before washing to prevent it form being stretched on the vacuum table. The object should be placed on top of a cotton sheet on top of the machine as this will draw the water through quicker and will protect the object. It will also protect the machine from any dirt removed. Once on the table, it can be sprayed gradually all over with water until cleaning is complete.

Setting up the table for washing
The object on the vacuum table
Washing the object with a water spray

Localised and differential washing
We were particularly looking at localised washing with additives such as IMS (Industrial Mentholated Spirits) and Synperonic A7 (detergent that reduces surface tension and cleans).

The solutions were made at 100ml quantities as follows:
50ml IMS and 50ml Water
100ml Water and a drop of Synperonic

These were used in conjunction with the vacuum table. The object had to be humidified prior to being washed on the table. The area needing attention was masked out using melinex and the object placed on top of a cotton sheet. Using a very fine brush, the IMS or Symperonic was added directly to areas such as foxing spots, hopefully reducing them, though it was not massively successful. The object should be placed recto up so that anything that is drawn out through the suction, comes out on the verso.

Washing localised areas

Making Solvent Set Tissue

Today was the final lecture from our visiting tutor who has been teaching us board reattachment. For her final instalment, we looked at solvent set tissue, which is not completely dissimilar to gelatine set tissue, and can also cross over into the heat set tissue theme as well – a multifunctional tool!

The reasons for using solvent set tissue, are twofold, the first being to be used when a book has such sensative leather that to get any paste or anything containing water would cause darkening – this form of paper repair is completely water free and therefore at no threat of causing this. The second key use is speed, as once set up, the process can be much quicker than using paste and tissue. It does have its downfalls as well, which is why it might not be used all the time – it is more permanent than wheat starch paste, if it gets erectly onto the leather rather than the repair tissue, it cannot be removed.

So the technique is as follows:

  • Initially tone some tissue in preparation for it to be pasted onto
  • Get the equipment ready, including a squeegee, a small screen print tray and a water trough to cover them both once used – the adhesive is extremely quick to dry and will not come off once stuck.
  • Humidify the toned tissue.
  • Lay the frame onto a sheet of melinex – this is what the adhesive will end up on.
  • Paste out small batches of adhesive along one edge of the screen and squeegee evenly over the rest of the frame.
  • Once evenly spread, remove the frame and lay out the toned tissue, ensuring a flat surface.
  • Allow to dry.
  • This can then be stored for future use.
  • When using, reactivate with solvent.

The adhesive used is called Lascoux and is an Acrylic glue. It is of the same family as PVA, though unlike PVA, it is completely non-reversable once dried. It is possible to reactivate the adhesive with solvent once dried, though it will not remove it, just make it sticky again. It is this method that is used to reactivate the adhesive on the tissue when you want to use the tissue on a book.

Essays, Letters and Poems 1781, vol 2

Having toned some japanese tissue for my repairs to the cover of this book, the next steps were able to happen in conjunction in one another, and I have been working on them steadily. Unfortunately it was at these following points where some hiccups occurred. My colleagues tell me that you learn more if you make mistakes to begin with, though I can’t help feeling a little disappointed in myself.

Having discussed various options with my tutors, we decided that I would remove the spine of the book as it is severely deteriorated and crumbling away. It would also give me practice in spine removal. If this book was of great importance, it is unlikely the spine would be removed and would be worked around. In order to save the spine, I used a Klucel G gel to adhere a strip of japanese tissue, this way, when lifting the spine, it will remain in tact and can be pasted back on again once I have completed the reback.

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Unfortunately, this was the first thing that went wrong, as the spine was so deteriorated, it was not lifting and instead was crumbling rather than coming off in one piece. This meant that having got what meagre bits off that I could, the remainder of the spine would have to be lifted with a poultice and would be unsalvageable.

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So I started a full spine removal with the hope of using methyl cellulose, but realised once I started to make it that it would have to be left for 24 hours, and unfortunately on the following day, it was much too runny and adding more methyl cellulose meant waiting another 24 hours. It was at this point I moved on to a wheat starch paste poultice, which I found worked well.

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Then came the second fiasco, having removed the spine, it became apparent that the first two cords had come loose and the sewing, completely eroded, making all the sections loose at this point and the text bock began to split. Rather than resew the book, my tutor decided that it would be better to paste down the cords and hold it together whilst they dried, therefore keeping it together, almost like the modern perfect binding (a ridiculous name given the technique).

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At the same time that all these problems were occurring, I was also able to consolidate the corners of the book boards and cover them with my specially prepared tissue, which, once dried, all looks okay. I will have to tweak the colour a bit and darken it and am practicing on some dummy boards at the moment, so hopefully they will not be so visible in the end.

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Making Toned Tissue for Paper Repairs

Tissue toning is something I have only done briefly before this lecture, and not one I had had any instruction in. Having previously had a thorough introduction into pulp repairs with Alan Buchanan, this particular process of toning tissue seemed to make a lot more sense than perhaps it had done previously.

It was necessary to learn to and tone tissue in order to move ahead with our board attachment lectures. The use of japanese tissue is now essential in the repair of books and paper, and has more strength than one might imagine, indeed a hinge repair in japanese tissue is often enough to hold a board onto a book for the foreseeable future, though to look at it, it almost seems impossible.

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The technique for this tissue toning, was to create a colour pallet similar to the colours of the book cover in question. This was done using different acrylic colours, such as burnt umber and ocre, these can be mixed on a sheet of melinex as an artists pallet is. Once the desired colour is reached, the pigment is then dabbed onto the tissue using a damp piece of cotton wool. This means that it is possible to get a meddly of colours on the tissue.

Personally I was not so enamoured with this particular method. I found both the cotton wool and the tissue would soak up the pigment too quickly to get good coverage, and the tissue ended up looking too patchy and the fibres of the tissue would become damaged and fragile.

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An alternative method, which I personally prefer, is to make up a pallet of liquid colour in a relatively large quantity. Then the tissue is dipped into the liquid pigment. This way the colour is more consistent and will cover a larger area. It also does not put any strain on the tissue fibres, meaning they retain their strength. Once one tissue is toned, it is possible to add water to the pallet and get a lower percentage of pigment on another sheet, and so on until the pigment is gone and the tissue toning is quite pale.

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The negative is that it is important to get the right colour before you go ahead and tone the sheet, whereas in the former method, more colour can be added to get the toning correct. In both methods, colour can be added to the tissue once it has been added to the book to blend in the tissue. This is often done with black.

An alternative method, which I have yet to test, is using a spray gun to cover the tissue in the pigment. This should get a maximum coverage of pigment onto the tissue with a minimum effect or damage to the tissue.