Making the Invisible Visible

Katie Cook

Archaeological objects can be fascinating and beautiful artworks all on their own. Think of the Venus de Milo or the Winged Victory of Samothrace, renowned for their beauty despite the fact that both are incomplete. The really important bits of archaeology, however, are the small everyday objects that inform us about the lives of people: the pottery, the remnants of meals, the waste from the production of various crafts. These objects are valuable when they have context, that is information about precisely where they came from within the geography and time line of a site.

Recently, I was working on an archaeological ceramic, a large body sherd from a storage jar found at Tell Jemmeh in Palestine (EXXXVI.49/75), which had lost its context. Without context, this piece of pottery had lost its ability to inform archaeologists about production, decoration, vessel shape and origins of the object within its site, as it could have come from any place within it and any time period.


The whole (section) of the storage jar EXXXVI.49/75, pre-treatment

While cleaning, though, I noticed traces of blue writing, which is readily observable on many other Petrie objects which were marked in the field with their context information. Doesn’t look like much to start with, though, does it?


Having the context information would be very helpful, though! So I undertook a series of imaging tests in order to try and make the faint traces visible enough to read. My first attempt was to examine the object under ultraviolet (UV) light. If it fluoresced, that would make it much more apparent. Unfortunately, it didn’t. While the traces did darken under infrared (IR) light, that wasn’t enough to make it readable, either.

My next attempt was to delve into photoshopping high quality images to manipulate the writing into visibility. And that worked! To one extent or another. I came up with a few final images using a variety of techniques:


Stuart Laidlaw, one of the photographers at the IoA, kindly tried his hand at bringing the writing up as well, and had a bit more success in keeping the colour visible than I did:


Luckily, though faint, it is just enough to make out what looks like HK 180, a context number that Rachael Sparks, the Keeper of Collections at UCL for the Petrie Palestinian Collection, was able to confirm as a viable context number for the site of Tell Jemmeh. It looks like the pot has a context after all, which makes it a far more valuable research tool!

All images are provided courtesy of the UCL Institute of Archaeology Collections (


An Update from the Working World

In addition to the current students in the MSc program, some past students occasionally have a chance to update us on how things are proceeding as they move on to their careers in the wider world of conservation.

Anna Funke (MSc 2014-2016)

I am from the UCL conservation class of 2016 and am now taking the first steps as a fully-fledged conservator.

After having lived in London for seven years, I decided that I wanted to go back to the States. So during my internship year, I applied to a wide variety of internships and fellowships all over the US, so that I would have a place to go after handing in my dissertation in September.

In the end, I did the Materials Research internship with the National Centre for Preservation Technology and Training (NCPTT) based in Natchitoches, Louisiana. The centre is part of the National Parks Service and runs a wide variety of scientific studies related to the preservation of North American heritage. I was originally supposed to be here for ten weeks but will now be staying for a little longer, which gives me time to get involved with more projects as well as elaborate on my original research.



Anna in front of NCPTT


While here, I have been running a study on the use of chelating agents to remove iron stains from marble. This has always been a challenging treatment because the acidity of the chelating agent will cause damage to the calcium carbonate in the marble, which can lead to etching. The aim of this study has been to gather data on the damage done to marble by the use of chelating agents, which could then be combined with data on their effectiveness at stain removal. Five different chelators were tested both at pH 9.2 and pH 10. Based on this combined data, the tested treatment solutions could be ranked according to their effects both on the marble and the staining.



Anna cleaning samples after treatment, unstained samples, and stained samples


Now that I have completed the data collected on this project, I will get involved with a study on the effectiveness of different glazing agents in the preservation of historic windows. For this I will be testing the durability of different products using a freeze-thaw chamber.

While I have been here, I have learned how to operate and interpret the data from a wide variety of scientific instruments available to conservation, as well as how to effectively design and run a study in materials testing. It has been a great way of learning more about material science and conservation research.

It has also been interesting working for an organization that is very focused on conservation communications. I have written several blog posts, given a lecture and recorded a podcast in the short time that I have been here. Finally, it has also provided me with an interesting research project, which I can now publish and present at conferences, which will hopefully help me further in meeting people throughout conservation.



Anna taking colorimetry readings on stained samples