Itsy bitsy, teeny weeny, yellow… sample?


Small gamboge sample


Large gamboge sample

Picasso once said there is no blue without orange and without yellow. While I cannot speak to his artistic sensibilities, I would add that there is no green without blue and without yellow. In order to elucidate the blue and yellow components of a green optical mixture, this project aims to design procedures for the individual blue and yellow dyes. The procedures for ┬áthe yellows Stil de Grain, and reseda lake and the blues indigo, azurite, and Prussian blue were completed by my predecessors and taught to me. The yellow dye gamboge, however, has not panned out as well. It is a large organic molecule that is bound in an insoluble resin, not the easiest dye to mix with our water-based silver nanoparticles. Our lab had yet to design a procedure and obtain a fingerprint spectrum for gamboge, though it became imminently necessary when optical mixtures were taken on. I looked at the structure of the molecule and tried to come up with reasons why previous treatments had failed. Was it the size? Long hydrophobic chain? Multiple aromatic rings? All of these certainly didn’t help it dissolve in water. Noticing a carboxylic group on the molecule, and with the advice of my PI, I decided to treat the gamboge with a strong base. After this first attempt failed, I tried various combinations of solvents until I finally obtained ┬ádecent results. Gamboge had been defeated! Or at least that was the way it seemed momentarily. Unfortunately, size does matter when it comes to paint sample analysis. I had been using large samples in these experimental runs, large meaning a generous 1 to 2 mm. Our goal to use the procedure on actual art samples meant that good results would need to be obtained using known samples that were less than a millimeter. Despite further adjustments, samples this small just refused to work. It seemed like the universe was playing games, giving good results one minute and taking them away the next. Looking forward, this is only a small hiccup in the experimental process. I’m optimistic that gamboge will work eventually, we just have to earn it first.

Check back soon!

Mary Matecki


  1. lmsevier says:

    What a great title for your post! Loved it! Absolutely made me laugh AND learn a lot about Gamboge. I’m sorry that the experiments are not working so far! But hang in there, it seems you have the right attitude. Those of us who are not in lab are really impressed with the work you are doing!