Today a painting from our collection was shipped to the Getty Conservation Lab in Los Angeles for conservation before its exhibition in an internationally traveling show. For the painting to have a safe journey, we wanted to protect it from fluctuations in temperature and humidity. When a painting on a wood support is subjected to changes in moisture content, the wood can shrink or expand, which, in turn, can weaken the adhesion between the paint and/or ground layers and the wood panel. A way to control the moisture content of a wood panel painting in transit is to construct a microclimate vitrine that uses the picture frame as the primary housing. One of our preparators, Holly, created this housing for the painting using the guidelines described in a publication by L. S. G. Sozanni (J.A.I.C., 1997, 36, 96-107).
Susan created this schematic to illustrate the construction of the microclimate vitrine:
Here’s what Holly did:
Frame 1: The back of the frame. We left the old felt lining in for shipping purposes only. It will ultimately be removed and replaced.
Frame 2: Here I am fitting the pre-assembled spacer to the back of the frame to make sure it all goes together OK.
Frame 3: Frame with spacer. The back of the spacer is rabbeted to receive the back piece of plex, which will be held in place by four wood strips. Here, the lower and left pieces have been removed.
Step 4: The spacer has been colored with acrylic, and attached to the back of the frame.
Step 5: The painting is centered in the frame using paper spacers.
Step 6: Placing the plex over the back. (Notice that it’s difficult to see the plexiglass backing- Optium is a specially designed plexiglass that is anti-reflective.)
Step 7: The wood strips that hold in the plex are ready to be screwed in place.
Steps 8 and 9: Ready for shipping:
Cross-Sections 
Very informative – looks great!
Bravo everyone!
Any word from the Getty on its arrival?
It arrived safely!
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so generous of you to share such information. well done indeed for explaining the whole procedure so well. you have correctly indicated that this closed system should be considered only on a temporary basis. the wood of the painting’s support and your additional spacer, in particular, emit acids. these organic acids remain trapped within the closed system and gradually accumulates till reaching high concentrations which can be damaging to the paint layer. i am very interested to know what happened to this painting, particularly how it was sealed better in its frame at the Getty. i really want to learn more on this subject since i have been entrusted with the enclosure of a very problematic painting and have been researching microclimate enclosures for a very long time. and am finding it very challenging since the actual step-by-step procedures on the construction of such sealed enclosures (including a full description of all materials used) is hardly shared and published.
thank you