The comments in my last post about our new computed radiography (CR) system spurred me into writing a second post about this topic.
In the comments on that last post Karen T discussed the importance of being able to make a 1:1 comparison between a radiograph and a painting, and then Christina responded with some first-hand experience with our new system. I confess, though: I cheated a bit and asked Christina to answer that question because, after all, Christina is an experienced paintings conservator here at the IMA, and I’m not.
Christina and I were talking about all of this when the Chief Conservator, David Miller, walked into the lab and joined the discussion (you can find out more about both of them on the Mainardi web page). To make a long story longer, the three of us decided to put together an example that illustrates how the new system handles the 1:1 comparison issue. So David and Christina printed out an image to demonstrate a 1:1 comparison of the radiograph and the painting. The photo above is of Christina holding a 13” x 19” print out of a radiograph of the IMA’s Edward Hopper’s 1943 painting Hotel Lobby. The painting was fully radiographed as part of a technical study of Hopper’s painting technique for an exhibition (and catalogue) opening at the IMA in August of 2008, called Edward Hopper; Paper to Paint, that explores the relationship of the artist’s drawings and studies to the finished painting.
Here you can see a close up of the 1:1 comparison. You’ll have to wait for the exhibition to open later this year to find out more about what was being looked at in this painting, but in the mean time have a look in the bottom right corner of the radiograph and you can see a piece of hardware that is helping to keep the painting’s stretcher in place.
In case you want to know, here’s a spec sheet on our new printer and here’s a spec sheet on the 13” x 19” photo paper we used. Finally, you can go here and here to see two documents that discuss the Print Permanence Ratings for this printer and paper combination. And, if your super geeky like me you can watch part 1 and part 2 of our printer in action. Weeee … watch it print!
In addition to the two images I’ve shown here, I’ve uploaded some more to my Flickr page that attempt to illustrate the printing process and to show our comparison in the gallery.
Beyond the 1:1 comparison issue, there are a couple of other things to consider when comparing the use of film radiographs to digital. A lot of paintings (and objects) are bigger than a single piece of film or photo paper. With film, conservators often trim and combine multiple sheets onto a light box so that the assembled radiograph can be compared to a painting. It seems logical that the exact same thing could be done with a print out, but we haven’t had a reason to try it yet. However, one of intriguing tools of CR is the ability to make enlargements of certain sections of radiographs. And, within these images you can make measurements and a variety of annotations. The image below illustrates some of these functions.
As for the other comments about the conservation of radiographic images, I’d like to say thanks, Alison, for keeping the CR topic close to the broader issues. I think it’s important to keep it in context and I certainly don’t mind at all if the discussion gets broadened to include the archiving and sharing of film-based radiographs (though I think we should draw the line and not include the whole topic of conservation documentation in the digital form in this post – we could be here for months if not years if we got started on that one!).
Taking this post off topic, I want to point out one of my favorite punk bands: the X-Ray Spex; it doesn’t get much better than Warrior in Woolworths, and besides what conservator wouldn’t like a lead singer named Poly Styrene.
Anyway, please feel free to add a thought, comment, or question. As I mentioned, we haven’t had this equipment for very long and though we’ve mastered some aspects of it, to some extant we’re still finding our way with it.