May 1998 Volume 20 Number 2

Technical Exchange

Dean Yoder, Column Editor

Bogen rail system and Solux update

Because of our positive experience using the Bogen rail system for photography, we decided to adapt the same type of system to be used for inpainting. The system that we finally implemented consists of three elements: The Bogen Rail System, Luma low-voltage track and fixtures and Solux lamps. You may remember an earlier column about Solux lights. Once available only in 4700°K, they are now sold in two new color temperatures, 3500°K and 4100°K with 10°, 24° and 36° beam spreads.

This system has proven to be useful for the following reasons. It is suspended out of the way of foot traffic and can be easily placed as close to or as far from a work of art as is needed. The sliding, telescoping post is fully mobile and can be stowed out of the way when not in use. There is a versatile range of beam spreads and temperatures available for different inpainting needs (we have settled on the 4100°K, 36° beam spread for most projects with the 4100°K, 10° beam spread for matching dark colors).

In order to accommodate the new Solux lamps in the Luma fixtures, a strip of low-voltage track lighting was affixed to the Bogen mounting bracket (part #0955) - placed in a vertical position and attached to the telescopic post (#0915). This telescoping fixture, attached to a sliding carriage (#0925), is then slid into the system of free moving ceiling rails. Because each studio has slightly different needs, it is best to consult the catalog for the exact type of rails and mounting brackets.

We used the Luma track to power the fixtures from a single 600 watt transformer located on the ceiling rather than the typical setup of 50 watt transformers self-contained within each fixture. This decision was made partially to ensure the correct color temperature of the lamps (manufacturers commonly underdrive individual transformers to increase bulb-life; as a result, the color temperature of the bulb may be compromised). With a junction box fixed to the ceiling nearby, the system eliminates dangling cords and cables on the floor.

Since installing this system, we have more space in our studio as well as greater flexibility at our easels. We are especially pleased with the greater variety of Solux lamps.

Solux is a product of Wiko Ltd. and the CA distributor is TRAC sales company. Contact: Jim Hudspeth (415) 571-7200 Email for Wiko: WIKOLAMPS@aol.com Technical Info.: kevlight @vivanet.com Taylored Lighting's website: http://www.vivanet.com/~kevlight/index. htm.

Bogen can be contacted at info@bogen photo.com. Phone: (201) 818-9500, Fax: 818-9177. Their website is www.bogenphoto.com. Their catalog is also available at most large retail photography stores.

Luma low-voltage lighting system is a product of Ruud Lighting. Phone: (800) 236-7000, Fax: (800) 236-7500.

Dean Yoder

Slide mounts for treatment documentation

In a Distlist posting Ellen Rosenthal writes: My concern is about the potential long term effects of deteriorating paper mounts as opposed to deteriorating plastic; which would be a better choice?

I've used both cardboard and plastic mounts and would personally lean towards the plastic ones. The heat-sealable mounts from Kodak (at least in the late 1970's and early 80's) were made from what looks to be pretty low quality cardboard. The cardboard has a gray-brown color characteristic of unpurified wood pulp with a nice white paper outside.

I wouldn't rush out and change all of my old cardboard slide mounts for plastic though, because we have generally found that chromogenic color tends to be less sensitive to poor quality paper than black-and-white (silver), and the slide mounts are not in direct contact with the images. I also haven't seen any noticeable edge deterioration in old slides from the 50's and 60's in cardboard mounts. On the other side of the issue, I expect that harmful materials are migrating from the contact areas (including the unknown heat-set adhesive) of cardboard mounts.

However, if one is trying to store slides to last, then I assume that they are being stored under fairly decent conditions and consequently they will be less sensitive to harmful materials. (I often tell people that under good storage conditions we can be forgiven more for small sins such as so-so quality enclosures and that changing the enclosures can be done as time and money permit rather than needing to be done as a high priority.)

As for the plastic mounts, I had a discussion about them with R. Scott Williams at CCI back in the late 1980's. As he pointed out, the only two plastics that would really work with an automated slide mounting machines would be PVC or polystyrene.

None of the mounts that either of us had looked at were PVC and all seemed to be polystyrene. We both consider the polystyrene to be pretty benign and the history with polystyrene sheets and film reels seems to support that opinion. As far as additives go, plasticizers hadn't been found at the time, nor were they expected to be found. In addition, unlike cardboard mounts, the plastic ones snap together and don't require the use of adhesives.

It's all opinion, but polystyrene mounts are theoretically less potentially harmful than the cardboard mounts (even though I haven't yet seen damage that could specifically be attributed to the cardboard mounts).

Douglas Nishimura

Source for tubes for paste storage

In the Abbey Newsletter of December 1989 (p.147) there is a description of making paste and then storing it in sealed, sterilized tubes. This allows the paste to be stored without refrigeration for many months without becoming spoiled and, in fact, even after opening the tubes will not spoil for several weeks.

The result is that one only has to take an hour every four to six months to make enough paste for four or five people. Thus there is a savings in time, but also in materials since no paste has to be thrown away due to spoilage.

I "rediscovered" this system while in Sweden last year. The problem for us in America is finding a source for the tubes. A couple of us have tried several companies, but to no avail. One, Sheffield in Connecticut, was willing to sell the tubes but had an extremely large minimum order. Others did not even respond to requests for information. Unfortunately the Thomas register lists only a few companies, and they appear to be directed toward manufacturers rather than conservators.

I have found a source for the tubes abroad, however, and am preparing an order, which I expect to send in June. The tubes are lined metals with an adhesive sealant at the end. The paste is made in the usual manner, poured into the tubes and the end folded over to seal the tube. The tubes are then boiled to sterilize the contents. They need no refrigeration, even after being opened.

These tubes will be about half the size of a toothpaste tube (25 mm in diameter and 142 mm long), and should run about $1.50 to $1.75 each plus postage from Seattle. I won't know the final price until I get the order together. If you are interested in participating in this order please let me know via email. Markandersson@hotmail.com

Mark Andersson

Objects stabilization bag

I'd like to make conservators aware of a superior objects stabilization bag made for our laboratory by JNM Associates in the San Francisco Bay Area.

The bags are made of washed muslin, with an outer sleeve of 100% cotton stockinette material, filled with large grain clean sand (grog), which contains no salts or silicas and is 100% inert. Another version has an inner bag of nylon with an outer bag of cotton stockinette.

The bags come in two sizes, approx. 3" x 15" and 3" x 26", and are ideal for holding objects down in storage, or for supporting small sculptures and other objects on the work table while performing conservation treatment. We are thrilled with this product and believe that the cost is very reasonable.

Bag 1 (muslin/stockinette)
small - $16.50; large - $20.00
Bag 2 (nylon/stockinette)
small - $12.50; large - $16.50

Bags without the inner bag design, less expensive, and custom designs are available. Contact: Joan Dsouza Marston, 2594 Greendale Drive, South San Francisco, CA 94080. (650) 866-4265. bjmarston@hotmail.com

Elisabeth Cornu

Portable microscopes

The following series of items appeared on the Distlist in response to this query about inexpensive, battery-operated, portable microscopes.

At a recent workshop on the identification of prints, we used a number of battery-operated portable microscopes in the 7X, 30X and 50X range. They were quite inexpensive as they were purchased for approximately US$12 each. Their quality was not very good. Can anyone point us towards better quality instruments?

Luis Nadeau

I have purchased for field use, and also use in my lab, a Russian 10x microscope that is extremely sturdy, has very good optics, and cost me about 80 pounds sterling. In addition to coming on a bench stand, I found that I could easily adapt it for use on a large gooseneck for working on larger objects. It proved so popular that I had to fight the archaeobotanist to use it! I purchased it through a British distributor, but the company may be represented in America as well. Try contacting: Zenith Microscopes Technical and Optical Equipment Ltd. Zenith House, 69 Lawrence Road, Tottenham, London N15 4TG +44 181 802 0624 Fax: +44 181 809 0556

Howard Wellman

I'm not sure which brand of microscope you were using, and unfortunately, you usually get what you pay for. However, short of buying a hand-held microscope from Nikon for $150-200 US, you might try the Radio Shack models of hand-held microscopes. Yes they are cheap and the optics are not the best, but I believe they would last longer than a one-day workshop. I have never had one break down on me, and the image is always very bright, provided your batteries are still strong. They come in 30X and 100X (100X is often too high for photographic identification, which I was using them for). They are very inexpensive, around $6 for the 30X, and $12 for the 100X.

Tom Braun

The NEDCC has a regular program of workshops that it has presented over the years on the identification of photographs. Our senior conservator, Gary Albright, has made extensive use of the Panasonic Light Scope FF-393E from the Matsushita Electric Industrial Co., as the optics have proven quite good for this type of magnifier. They are available for $33.85 US from University Products. Hope this helps.

Karen E.K. Brown

and, finally:

I would like to add an addendum to my original message. It turned out that the problem was with the light bulbs Radio Shack had been using. They could not handle the voltage from two fresh AA alkaline batteries @ 1.5 Volts each as the bulbs are rated 2.25 V. The newer 30X microscopes have sharper optics and also have a slide-out 8X plastic lens built-in which comes in handy. The bulb is rated 2.33 V. and seems to handle the alkaline batteries. I personally installed 2.5 V. bulbs which are not quite as bright but they will last a long time. Another solution would be to use rechargeable batteries as they only produce 1.25 V.

Luis Nadeau

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