Pigment Microscopy

So in a similar theme to the previous post on pigments, this weeks microscopy lecture was also on pigments. I’m glad to say that I did follow this lecture considerably better than the previous microscopy one, perhaps as it was more about colours and pigment than the microscope itself.

Pigments in India, on market stall – photo (with thanks) by By Dan Brady – https://www.flickr.com/photos/11853009@N07/1382064216/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=3534510

Here we were learning to recognise and record pigment data from objects. It is possible to compare the pigments you find against known specimen samples, which can be bought or homemade from swatches, and also to compare them against published data, such as the Pigment Compendium. With experience, will also come the ability to recognise pigments without comparison to recorded data. Pigment samples can be acquired from various suppliers, and can be homemade as well. They can be relatively cheap and accessible and useful to help ID many traditional pigments, especially organic ones such as Palestine Blue. For a more in-depth insight into pigment recognition, I suggest a trip to your local science library!

The Chelsea filter is an interesting addition to a microscope when looking at pigments and can be used to look at blue and green pigments, with some appearing red when looking through the filter. It passes two narrow bands of light – yellow/green and red and was initially developed for the gem trade, to distinguish from high quality gems!

Pigments & organic colours used in manuscripts from Armenia & Egypt

This lecture took place a while ago now, and it has taken me a while to write anything about it, though that does not make it any less interesting. Unfortunately I have no pictures, so will endeavour to make it short. Our lecturer was Cheryl Porter who is a a specialist in pigments and had kindly given us her time as part of the Book and Paper ICON Group move to provide more specialist lectures, which was fantastic as her skills and experience are extensive.

Porter has been spending time in both Armenia and Egypt to study the pigments found in manuscripts over there. She concentrated on red and pink pigments for our lecture as there is such a huge depth of information on the subject as a whole, it could be impossible to cover all of it.

There was a specific type of red pigment found in Armenian manuscripts that they had initially found difficult to locate. After extensive research, Porter found that the pigment was made from female Armenian Cochineal beetles, specifically found in the base of the valley of Mount Arrarat. The earliest knowledge of the use of this pigment was in 1743 and was not just used for colouring manuscripts, but also as a fine dye for fabrics and silks.

Porter duly went on a beetle pilgrimage to the valley of Mount Arrarat and found disappointingly few beetles and almost no-one who knew anything about them. However luck was on her side as she met a father from the Khor Virap Monastary who was familiar with the pigment and was even able to show Porter how to formulate it from the small amount of beetles that they had found, which included keeping them in alcohol for about a year to separate the fats – this would be after slow roasting them in order to dessicate them, so a relatively gruesome process!

The number of beetles has reduced for several reasons, including the building of a chemical factory after the war, and using it as a military area, there is also no control over the animals, which are free to roam the area and eat all the grass, removing any food source for the beetles. Grass is also destroyed by using the land for crop growing, so sadly the beetle colony is reducing year by year.