Breanna – Summer Week 4

This week ended up being very exciting.  First, I successfully took a spectra of Allison’s ring using the horizontal macro adaptor.  This is important because it means that next week I’ll be able to start using it on the Book of Hours!  If this works out alright then I can analyze those tricky middle pages which are unreachable via the stage.  Before I go for the blues, though, I’ll take spectra of the known MgS just to really make sure that everything is running smoothly.

While fussing with the macro adaptor I also found that doing a full calibration of the Raman does not necessarily put the Rayleigh peak at 0 where it should be.  This is probably the underlying reason as to why the spectra that we think are azurite are all a little bit off in a systematic way and why I was getting peaks at ~515 for Si.  I’ve started manually moving the Rayleigh peak to its proper place after calibrating, and so far this has fixed all discrepancies beautifully.  Unfortunately I have no idea why the calibration isn’t doing its job properly.  I went through and tested all of the gratings, and it seems that using the 532 nm at 1800T gives the best data w/o manually calibrating.  Overall, however, the 785 nm laser is less off.  Interesting indeed.  For now I’ll keep moving that peak over.

I was also able to complete my goal of just taking more spectra of the blues without the adaptor.  I checked in several different locations and everything seems to be azurite.  I can’t get to any bits with the flowers without the adaptor, though, so next week will help to confirm what I suspect is a whole bunch more azurite.

Finally, I took spectra of the two gorgeous miniatures that are not part of the Book of Hours but instead were cut out of another work.  Each features what is probably a different saint and each of these figures wears a blue robe.  The smaller miniature’s robe turned out to be filled in with azurite just like in the Book of Hours, but the larger miniature gave me quite the shock.  We have Lapis Lazuli, people!!!!  Lapis Lazuli was a very expensive mineral (priced akin to gold) that was used in only the finest manuscripts.  The pigment was often called Ultramarine, and while it looks very similar to azurite under the microscope it has a very different spectra.  I got a beautiful read and just about peed my pants.  Wow.

So, goals achieved:  Messed with the adaptor some more and took spectra of as many blues as I could.

Goals not achieved:  Still haven’t gotten to mapping.

Next week:  Use the horizontal adaptor on the manuscript and perhaps finally do mapping.  I’d also like to get my hands on the second manuscript we have as well, but I don’t know if that will be feasible.


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