The Final Touch

Well, the job is done.

The item has been cleaned, stabilized, repaired and rehoused.

It has gone from this in 1913:

Photograph taken in 1913

To this in 2011:

Item before treatment

And this in 2012:

Item after treatment

The treatment that eventually unfolded was different to that which was proposed. This is often the case as the fragility and nature of the item becomes more apparent after thorough examination and documentation.

It is also the nature of the Conservation profession to seek to stabilize an item in its current form to enable the evidence of the item’s life to still be apparent to the viewer. We are not trying to take something back to “as new” condition.

The item has now been placed in cold storage (10oC) to slow down any inherent deterioration. It is being stored flat (not folded even though it is nearly 2.5m long) and horizontal in a thick acid-free folder so that it is fully supported all over, and the brittle paper does not have to support its own weight.

Our work will ensure that all Australians will be able to view and appreciate the item for decades to come.

November 2012

Filling the Void…

Having repaired and stabilized the print from the back, it is now time to fill the losses from the front to make them less visually distracting.

Previously, the losses were filled from the back with a simple Japanese tissue repair to provide a base for the fill:

Repaired loss before filling

From here, the print was placed on the light table and a piece of Mylar was laid over the loss. The Mylar acts as a protective layer over the print. The toned archival paper is laid over the loss and weighted down so it won’t move:

Fill paper placed over the loss

The exact outline of the loss is traced onto the archival fill paper lightly with pencil:

Tracing the outline

The fill is then cut out with surgical scissors and checked that it fits:

Checking the shape of the fill

The repair tissue is wet out with a thin paste solution to reactivate the remoistenable adhesive layer, and to add a bit more strength to the adhesive to hold the stiffer archival paper in place:

Pasting out the repair

Once the fill is in place it is allowed to dry between Reemay and blotters under weights.

Then the pencil lines are erased from the repair:

Fill with pencil lines

Fill with pencil lines erased

And the fill paper trimmed to the edge of the item:

Fill paper after trimming

This was the final step in the treatment process. Now all the item needs is after treatment photography and to be returned to storage. See the before and after versions next time…..

Now that the print is repaired, the losses on the edges will be filled so that they become less obvious to the viewer.
Three techniques for toning infill papers were tried:
1. Paper Goo: This is an extract of aged paper. Torn up vintage paper is soaked in water and heated to reduce the water and concentrate the solution:

Paper extract being extracted

Dried paper extract

The compound is then brought to a neutral pH with the addition of calcium hydroxide as it is reconstituted:

Paper extract being reconstituted with calcium hydroxide

The solution is used to soak strips of pure cellulose machine made paper:

Pure cellulose paper dyed with paper extract

It worked, but the tone was too yellow when compared to the front of the print:

Original item compared to pure cellulose paper dyed with paper extract

So, I tried again…

2. The same machine made paper was soaked in a solution of water colour paints to try and produce a better tone:

Watercolour toned paper

However, while this was being done, a stash of toned paper which had been produced for a similar treatment was rediscovered…

3. Inkjet colour matching:
A previous treatment in the Canberra lab on a ferrogallic print produced a number of sheets of acid free paper printed with colour matched inkjet ink. A digital image had been taken of the print, colour matched to the original and sections of solid colour printed out:

Inkjet ink on archival paper

One of these colours matched this ferrogallic print almost perfectly:

Original item compared to inkjet print out

So, I got lucky! This paper will be used to fill in the losses on each short edge of the print.

With the tears stabilised with BEVA sutures, they are now in place and can be repaired along their entire length.

Laying down long repair patches

One centimetre wide strips of remoistenable lining paper were torn from the sheet. Tearing the paper provides an edge of feathery fibres which creates more surface area for the adhesive to stick to and we end up with a better grip. The strips are gently wet out, allowed to air dry slightly, positioned over the tear, then burnished into place. They are then placed under weight and allowed to dry without movement. This work is carried out on the light table so that the line of the tear can be followed exactly.
With the combination of sutures and thin tissue strips, the tears are now strong and not at risk of getting worse during handling.

Repair patches in place

At the same time, the largest losses will be in-filled with tissue. This will provide a support for colour toned patches to make the losses less apparent from the front.
Firstly, the object is covered with Mylar as a protective barrier layer. The repair tissue is placed over the loss and the tissue perforated with a pointed probe around the edge of the loss.

Perforating the repair tissue through Mylar

Then, the perforated line is wet out with deionized water to facilitate tearing the patch out. It is pasted or wet out around the overlap and carefully positioned over the loss. The patch is then weighted down until dry and set into place:

Wet tearing over perforations

The same system can be used to infill losses and repair many small edge tears at the same time:

Fill tissue used as edge repair strip

Once all of the tears on each end are repaired from the back, the item will be flipped over and the losses infilled with toned paper from the front. But that’s for next time….

With a better understanding of how to repair this badly discoloured item after all the testing detailed in Chapter 9, the work could begin:

BEVA 371 film was applied to strips of Bib Tengujo Japanese tissue. This is a very fine, hand-crafted tissue made from Paper Mulberry (or Kozo) fibres. It is used in conservation when translucent repairs are required.

BEVA film applied to tissue

These strips were cut into individual sutures around 3mm wide and 13mm long:

Individual suture

The sutures were individually attached to the back of the print, working from the front. Silicone release film (a plastic sheet that has a non-stick surface) was inserted between the two layers of torn paper so that when the sutures were tacked in place, there was no risk of accidentally adhering them to the work surface.

Silicone release Mylar in place

Sutures in place

Once all the sutures were inplace, the tears were aligned and the sutures tacked down to hold the tear in place:

All sutures holding tears in alignment

Each individual suture was sealed into place with a heated spatula:

Adhering individual sutures

This ensured the sutures were as translucent as possible to avoid obscuring any information:

Sutures before completed adhesion

Sutures after complete adhesion

The area of old masking tape repairs has gone from this:

Before masking tape removal

To this:

After masking tape removal

And now this:

Tears sutured into place

There is still one more step to go: next, all the tears will be repaired along their entire length for strength and durability.

Our poor sacrificial item has been torn up and punctured through, to replicate the types of damage to be repaired on The Key.

Applied puncture

Applied tear with overlapping sections

As mentioned in our last post, several repair techniques were trialled which involved mimimal use of water, to avoid causing tide lines in the areas of severe discolouration.
The first technique was a traditional one, using wheat starch paste made with water and applied to a thin hand-made Japanese tissue. The tissue was pasted out onto blotter before applying it to the item, to absorb as much water out of it as possible, but it still wasn’t dry enough, and a faint tideline did form on one end of the repair:

Starch on tissue repair, with tideline circled

Test number two used a modified cellulose adhesive (called Ethulose) dissolved in ethanol applied to the same hand-made Japanese tissue. It looked promising, but the adhesive bond proved too weak for this application:

Modified cellulose adhesive in ethanol, on Japanese tissue

The third test trialled a patch made from remoistenable Japanese tissue. The tissue had a mixture of starch paste and methyl cellulose (both made with water) applied to it, which was allowed to dry; the paper was then torn to the right size and shape for the repair. The adhesive was re-activated with a very light application of moisture from an artists’ brush. This technique worked well, providing a strong bond with an unobtrusive tissue patch, and did not cause tidelines:

Remoistenable water-based adhesive on Japanese tissue

A remoistenable repair using the ethanol-based adhesive was not trialled due to the weak nature of the adhesive evident from the second test described above.

The fourth and final test used BEVA 371 film on a very thin Japanese tissue called Tengujo. BEVA film comes in a roll on release papers, and firstly it was applied to the Tengujo using a heated spatula set to 70°C. This was then cut to shape and applied to the tear with the same heated spatula. The technique was highly successful as it provided a strong bond and an even less obvious patch than the remoistenable adhesive. The patches applied were very small but effective, which suggested they would be useful as sutures (small repair strips applied along a tear at intervals):

BEVA suture in place on tear

BEVA patch in place on puncture

After evaluating all the test results, the course of action I am choosing to take is to use small sutures of BEVA film on Tengujo tissue to hold the tears in place where the overlaps change direction:

Incorrectly overlapped tear

Correctly overlapped tear

The suturing will be done from the front, to ensure all the tears are correctly aligned, then the whole item will be turned over and each tear repaired along its entire length.

I have thought long and hard about what would be the best approach to take to repair the tears in The Key. My initial thought was to use a remoistenable lining paper, but there are two problems with repairing it in this manner:

1. The yellow discolouration throughout the print is water soluble, which means that if an aqueous adhesive is applied to it, the yellow discolouration may move with moisture and dry with a dark ring around the edge of the area (known as “tide lines”). This is very likely to happen as there are lots of areas on the print where it has already occurred (refer to blog Chapter Five); and,
    
2. There are faint annotations on the back of the print, which means that an overall lining of the print will cover these and make them almost impossible to read, and a partial lining would look cumbersome and mean some areas are supported while other areas are not.

To test various repair techniques and decide on the best one, a sacrificial item was sourced at an op-shop:

Sacrificial trial object - front view

This item has extensive yellow discolouration and iron gall ink annotations, and is brittle and easily damaged, just like The Key.  I found that the yellow discolouration moves on the trial object just as it does on The Key, so the potential for forming tide lines on The Key can be accurately replicated.

Trial object: application of water to yellow discolouration

Trial object: tide line formed

Different repair techniques will be trialled on this object to ensure a technique can be developed which does not cause movement of the yellow discolouration. This will mean that the tears on The Key can be stabilized individually rather than lining the entire back surface, therefore allowing the annotations on the back to remain visible.

The repair techniques to be trialled include:

1. Traditional repair with wheat starch paste and hand-made Japanese tissue
2. Traditional repair with solvent based adhesive like a modified cellulose and hand-made Japanese tissue
3. An aqueous (water-based) remoistenable tissue patch
4. A non-aqueous remoistenable tissue patch
5. A low temperature heat activated adhesive like BEVA 371 on tissue
6. Small “sutures” made from Japanese tissue adhered with wheat starch paste
7. Small “sutures” made from Japanese tissue adhered with a non-aqueous modified cellulose adhesive.

All of these techniques will introduce the smallest amount of moisture possible and also cause the least amount of cockling along the interface between the adhered and non-adhered areas. The technique deemed the most successful on the trial object will be put into place on The Key.

Following the large scale surface cleaning step, the next step – tape removal – seems minor by comparison.
There are two strips of masking tape on the back of one end of the print:

Masking tape on back of The Key

And a temporary repair that was applied when the item first came in to us to stabilise an at-risk area of the print:

Temporary repair strip

All three of these repairs will be removed.
The temporary repair was easily removed just by peeling the tissue away from the print by hand. This is exactly how the Conservation staff would have expected the repair strip to behave. It was a reversible repair with minimal impact on the object.

After removal of temporary repair strip

The masking tape proved to be fairly easy to remove, too. Luckily, the adhesive layer was still sticky and had not become yellow and brittle. This meant that the tape carrier could be removed by warming the adhesive layer with a heated spatula to soften the adhesive and lift the carrier off.

Using a heated spatula to remove masking tape

Residual adhesive was partially removed by warming the adhesive in contact with a square of blotting paper. The soft texture of the blotter allowed the adhesive to cling to it and be lifted away.

Adhesive residue from masking tape transferred to blotter

The remaining adhesive will have to be removed with solvents. The print is too long to fit in the fume hood, but luckily only one end needed to be in there, so with some extra support, The Key turned into The Bridge.

End of print in fume hood, for solvent application

The remaining adhesive was removed using small hand rolled cotton swabs dipped in tetrachloroethylene. This solvent is known to work well on sticky masking tape adhesive, and it lived up to its reputation. The adhesive was removed, but as is so often the case with pressure sensitive tapes, some degree of staining was left behind.

Removing adhesive residue with solvent on cotton swab

The print is now (temporarily) in a more fragile state as the torn right hand end is no longer held together with masking tape.

Before masking tape removal

After masking tape removal

This entire area will be stabilised during the repair and lining stage.

Treatment Stage 1 – Surface Cleaning

It is generally the case that a conservation treatment begins with surface cleaning. Dry particulate matter needs to be removed off the surface of the item so that any treatment steps involving liquids won’t drive that dirt further into the fibres of the paper.

This item, being so large, called for a cleaning technique that could cover broad areas of paper but be very gentle at the same time. The method chosen for the back was crumbed vinyl eraser.

Bag of eraser crumbs

This is worked onto the surface of the print using a gloved hand. The surface dirt sticks to the crumbs and they become discoloured. Once discoloured, the crumbs are brushed away, and fresh crumbs used in their place. This is repeated in a systematic way across the full length and width of the object until it is completely cleaned. Areas of pencil annotation were not cleaned so as to avoid erasing any of the pencil. Ink annotations can be cleaned very gently using this method. As you can see from the images, quite a bit of dirt was removed. Cleaning the back of the print in this manner took around 3 hours.

Working crumbed eraser over the surface of the print

Latex gloves after surface cleaning

These two techniques combined produce a successful outcome.

Localised cleaning before application of vinyl eraser

 

Localised cleaning after application of crumbed eraser

 

Localised cleaning after application of vinyl eraser

The front of the object was a different matter. It is much more damaged and fragile than the back. Cleaning the front was investigated very closely, including microscopic examination, to see if the paper fibres were being disturbed during cleaning.

Cheryl trials surface cleaning using a microscope

Unfortunately, they were being picked up, so neither crumbed eraser, nor solid vinyl eraser, was gentle enough. A similar print which has been treated in the lab previously was cleaned using a product called Smoke Sponge. This was used at the National Library after their fire in 1985 to clean soot from their books.
Used with a gentle dabbing motion rather than rubbing, the dirt can be picked up off the surface of the print with little impact of the paper fibers.

Cleaning a loose fragment using the smoke sponge

Smoke sponge after cleaning, showing adhered dirt

It was surprising how much dirt was removed (although the print didn’t actually look that much better – such is life!)

Again, areas of pencil annotation were avoided, but areas of ink annotation could be cleaned. Edges and tears also have to cleaned very carefully to avoid dislodging loose fibres or fragile edges.
Cleaning the front of the print in this manner took around 4 hours.
So in total, investigating and surface cleaning the print took a couple of days. It is not the sort of work you can do 8 hours straight. You need regular eye and muscle breaks. The work needs to be gentle on the body as well as the print.

So, having thoroughly gone over The Key from top to bottom, front to back and left to right, now is the time to come up with a treatment proposal to stabilise it.

Conservation treatments don’t try to “restore” the item to its original state. Instead, conservators remove damaging materials and products as much as possible, stabilise the item once that threat is removed and place it into a storage environment where the ongoing deterioration will be slowed right down.

This item is a bit tricky though. As described previously, it was produced using iron salts suspended in gelatine which were developed in acidic chemicals. These acidic chemicals have not only made the paper quite brittle, but they seem to have damaged the residual gelatine as well.

A test was carried out on one of the small loose fragments of the print (about 1cm x 1.5cm). It was washed in deionized water and dried on a blotter.

NAA: A710, 51 - fragment after water wash, showing brown degradation product washed out

After this simple step the paper actually seemed thinner and softer, which poses the question: did some of the original material wash away (such as the residual gelatine), or did washing the degradation products out of the paper return it to a more flexible state? If it is the first scenario, it is a bad result – we wouldn’t want to remove original material irreversibly from the object. If it is the second scenario, it is a good result, as it has restored some flexibility to the paper, which may not now be as prone to physical damage.

What to do???

As much as we might like to try and wash the print with water to remove acidic degradation products, we run the risk of washing out the image as well, which would further reduce the density of the already faded lines. So, unfortunately, washing the print in water is probably out of the question. 

Could we wash the print in an organic solvent to try and wash some of the degradation product out, but not risk solubilizing the image? A second fragment was washed in ethanol.

NAA: A710, 51 - fragment in ethanol bath

Unfortunately, nothing was washed out of the fragment, so this procedure wasn’t going to get us anywhere.

Forgetting about “wet” cleaning then, we can turn our attention to “dry” cleaning. The print can be surface cleaned (or “dry” cleaned) with erasers, front and back. This will remove loose surface dirt and brighten up the paper a bit. The front surface will have to be cleaned very carefully to avoid any pencil annotations, and to avoid disturbing the paper fibres which have become brittle and fragile with age.

Remember, too, this item is more than 2.3m long and 0.7m wide, so it is going to take QUITE A WHILE to surface clean it with a regular eraser!

Once the print has been cleaned, the masking tape will be removed so that the tears can be repaired more appropriately and more thoroughly. The full length of the tears will be repaired so that the whole vulnerable area is supported, rather than the current hit and miss approach.

NAA: A710, 51 - old repairs

The tears will be repaired using a thin tissue paper coated with a starch based adhesive. These are called “remoistenable” tissues and are something we make up in the lab. We make them ourselves so we can control the type of tissue used, the size of the sheet of tissue used and the formulation of the adhesive. The preparation of the tissue and a trial run of using them will be detailed in another blog post.

Once the individual tears have been repaired and allowed to dry, the entire print will be lined using whole sheets of remoistenable tissue. This will give strength to the object, keep it flat and provide a margin around the edges to hinge and mount the print for exhibition

The reason we use remoistenable tissue is so that we can tightly control how much moisture is being introduced to the object during the treatment. Too much moisture could cause the image to bleed, or tide lines to form (these are dark lines that form around small areas that wet out more than the adjacent areas)

NAA: A710, 51 - pre-existing tide lines

After the print has been lined onto tissue, the areas of loss will be in-filled with toned paper. This will serve to reduce the visual impact of the losses making them less distracting to the viewer.

Once the print has been repaired, it will be dried between acid free blotters, paper-makers felts and pressing boards to keep it flat and wrinkle free.

The last stage in the treatment will be to mat and house The Key for safe storage.

Stay tuned to see if it all goes to plan…