Chinese lacquer

The story so far in Cons DistList Instance: 14:64 I asked if anyone
else had X-rayed Chinese lacquer bowls of the Sung Dynasty, as I had
just X-rayed one and had a surprising dark band around the rim, I
wondered if the X-ray had found that the bowel was of two types of
wood. Then in 14.65 I was asked more questions I think more
explanation is in order.

The bowel is red on all of the inside surface, black on all of the
outside surface. I took several top view X-rays which showed that
there was a textile in the lacquer ware (I also did 2 black lacquer
bowls that also have textile, did the Chinese invent a fibre glass
fore runner with this?) and a central indention to show that it was
lathe turned. Then I turned the bowl through 90 degrees, held it on
a foam support and held a small piece of film with foam close to the
side of the bowl and blasted twice more (30-40 KV 4-3 minutes Kodak
M film, no filters)

My other experienced X-ray techniques colleague thinks it is to do
with the lacquer, but the line is very straight and the effect
cannot be seen at all with the eye, if it is all in the opaqueness
that the mercury salt gives, the manufacturer would have had to have
applied 'masking tape' painted the mercury sulphide lacquer, remove
tape, and then painted it all over with a less X-ray opaque red
lacquer, not impossible, but the reason why cannot be seen now,
unless it has degraded as the red looks just the same, which was one
of the reasons I asked.

I will try IR too inspired by the other message on 13.65 on
fluorescence

I will see if it is possible to set up a web page of pictures.
Today, I looked at a 1960s Pepsi fridge, to assess it before being
cleaned by workmen, the variety of life of a conservator!

Paul Harrison
Hong Kong Govt Metals Conservator


                                  ***
                  Conservation DistList Instance 15:1
                  Distributed: Wednesday, June 6, 2001
                        Message Id: cdl-15-1-006
                                  ***