Dirt off your shoulder…

One of the great challenges in museums is keeping the collection clean once it’s on display – dust & dirt are our number one enemy! This isn’t a new problem either, as far back as the mid 1800’s museum professionals have been worried about what the local environmental conditions were doing to their collections. Michael Faraday, yes he of ‘Faraday’s law’ and Cage did a lot of early work on the issue. Here at the V&A he looked into the effect of gas lighting used in display galleries and over at the National Gallery he was part of Committee looking into ‘Means and Expediency of preventing the Nuisance of Smoke from Fires and Furnaces.’

how clean is my road

Pollution map showing local area around the V&A . Notice that Cromwell Road, where the museum front entrance is located is labeled High, while the other surrounding roads are medium  – map courtesy of http://www.howpollutedismyroad.org.uk/roads.php

As the museum is located on a very busy and polluted street we monitor the museum regularly to see the level and type of dirt found in the museum. We even have a fancy machine that does this for us!

Dust monitor

Our dust monitor which is used to count the number of particles in the air and also to investigate their size. (c) Victoria and Albert Museum, London.

We also use it to our advantage, creating desiccated environments with special ‘dust’ that stops bugs and pests living in all the nooks and crannies in this maze like museum.

So why then have I been trying to make dirt and intentionally dust it over samples… Well it turns out when you want to test new cleaning methods you need something dirty to clean which leads directly to the question – What is dirt?

In an earlier blog post I showed an image of the ‘standard soil’ that was used in previous testing. We didn’t exactly like this soil, it looked a little too like paint for us so we carried on with the rest of the project while keeping an eye open for soil recipes. Our search yielded two results, which is two more than I predicted! The recipes are similar, there is a simple/basic one and a second more complex one. The simple recipe contained peat moss, cement, quartz, kaolin, iron oxide, mineral oil and carbon black. While the more complex recipe was the same as the simple recipe with the addition of chalk, gelatin and soluble starch. The complex one also split the recipe into wet and dry parts that would be mixed at the very end. The wet parts were the mineral oil and chloroform. To say a felt like a technical challenge from The Great British Bake Off would be an understatement!

Dirt mixture

The finished product! The two dirt recipes side by side with the left being the complex mixture without any liquid ingredients and the right being the simple mix with a little mineral oil.

Sourcing the ingredients lead me to conversations I thought I would never have – Most of the ingredients were kindly given to us from the other conservation studios. Book conservation supplied the gelatin and soluble starch as these are two products they work closely with. They use very pure/specialized versions though and when I called up to collect them I was asked if i wanted Cow or Deer gelatin and was it ok that the starch was low in gluten…

Gelatine

This image shows the difference between the Deer and Cow gelatine – the deer getlatine had larger particles so we used the cow. Not sure if would make much of a difference though!

Dirt recipe

The rest of the dry ingredients. Top: Carbon black – this is truly the worst material I’ve ever worked with, its basically soot only purer and evil and gets on everything. Middle: Cement and Wheat Starch. Bottom: Quartz, Iron oxide (this is actually pigment grade) and Kaolin clay.

Applying the dirt was another issue we had to over come – The previous method used a bar coater that, due to the consistency of the soil, resulted in an uneven layer on our plastic samples… so we went back to reliving our dream of Bake Off glory and used muslin cloth to ‘dust’ the samples in dust which worked very well – it was easy to control the amount, where it landed and the muslin did a good job of keeping the size of the particles consistent. I will leave the samples to dry for a few days, hopefully the dirt will stick to the plastic and then next week, all going well I can test my cleaning protocols.

both dust

Two plastic samples covered in the soil. The left side had the dry complex soil applied to it while the right had the simple ‘street dirt’ soil. Also, we purposefully covered the left sample a little more than the right to see how much we needed to use.

Close up on dust

A close up of how the soil covered the sample.

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