Finishes

[melaniek]

What is the best finish to use for a display box that will contain a very old book - an archival finish. I am concerned about off-gassing affecting the fragile paper. Melanie

[nospambob]

[Andy Dingley]

What's "very old" here ? What's the binding style, the materials and the type of paper ?

What's "display" ? Open or closed ? How long is the book going to be in here ? Is this a transport or archival non-display case ?

What's on the page ? Illustrations ? Any light-sensitivity issues ?

How big is this book ? How heavy ? How strong is the binding in relation to the weight of the textblock ?

In general, I would suggest two broad (and rather crude) guidelines:

- Don't do this. Books are best stored by shelving them, not displaying them. Even when done to "best practice", a display of a book, especially open, is poorer for storage than quite casual shelving. In some cases this could be very damaging.

If you have to display, rotate. Change the book, or at least change the open page.

- Any reasonable sort of display box is OK. Books aren't fussy. Books and their bindings already contain quite enough nastiness on their own account - not many cases will add to this!

Let's assume you want a glass-topped display box with a cushion in it. Hopefully this is for short-term exhibition of a one-off, or else a rotating display.

Build the case from a stable non-reactive hardwood such as ash, beech, hornbeam or maple. If it has to be made of something else, line it with an inner box of lime (linden/basswood) or paulownia. Avoid oak, chestnut, walnut or tropicals. Avoid softwoods. Avoid dark timbers (in case of flood - most will stain). Don't use man-made boards.

Assemble the box with PVA glue (if glued). Don't use hide glue, don't use PU glue. Make sure the glue is well cured before using the box.

Consider ventilation openings. This depends on your gallery temperatures / humidities, and the likely display internal temperatures. Try instrumenting a test cabinet beforehand and measuring the env. conditions you get.

Make the lid so that it opens for easy access. Fit a securely locking stay or retainer to hold it open.

Glaze the lid with something sufficiently strong to support small children (possibly whilst dancing in wellingtons - I've seen it happen!). Consider anti-breakage film on the inside of glass, or at least tempered glass. Use laminated if there's a value issue (against either theft or breakage).

You have a choice of glass or Perspex (Lucite / acrylic). Glass is generally stronger, cheaper and scratch-resistant, Perspex can reduce UV damage, especially if you use a UV-absorbing grade. The right choice depends on the cabinet size, contents and display conditions.

Finish the inner surface of the box with plain white or grey paint. Use an acrylic (is this "latex" in the USA?) paint and make sure it's well cured before use. If you need a clear finish, use shellac. Don't use any oil or varnish finishes.

If you need an inner substrate, use normal conservation materials like foamboard or mounting board (acid buffered, as usual). If you use fabric drapes, make them plain unreactive cotton or linen. Foamboard can also be used for internal sunshades (but watch for reflections, or the sun moving during the day).

The book cushion to support the book should be the usual cushion materials - foamboard is easiest. Make the cushion to fit the book, particularly the spine width and angle. Don't fasten cushions down because they need to be interchanged for different books -- a badly fitting cushion damages bindings. Don't use man-made timber such as MDF for making book cushions - use stable softwoods if you must, and cover the top with mounting board.

If you need non-reactive interlayers, use polyester (Mylar) sheet.

Fit the usual level of thermometers, hygrometers, lightmeters and bug-traps (especially bug traps). Don't dehumidify - books don't like being drier than 45%, which is very easily obtained in an illuminated display and is very damaging to any book that's on display with the binding open.

Worry (a lot) about illumination levels on an open book, particularly about UV. Don't illuminate the case internally - if you do (only for the biggest of displays) then have a conservator / lighting engineer look at the design first. Remember that 250 lux (approx. domestic interior) is the limit for most books and that sensitive ones should be limited to 50 lux (inside a cinema). UV light should be < 75µw/lm and ideally

[melaniek]

Thanks for your in-depth response. The box is for a very old family bible - probably close to 100 years old. I already made the box - maple- plan to use glass and will finish it with shellac which is what I was thinking might be the best finish to use. I'm glad you concur.

[Andy Dingley]

You're welcome.

Nice to hear you're looking after it.

I did a flat clearance a while ago - deceased old lady neighbour, whose children showed up, collected the new TV and ran off. They left the photo albums and the bible (1870s) behind -- just not interested. How can anyone do that ?

[melaniek]

Beats me!