May 2002 Volume 22 Number 2

Technical Exchange

Albrecht Gumlich, column editor

It Pays to Shop

Comparison of prices, domestic and abroad: It is worthwhile to compare stock and prices of Kremer Pigments in N.Y. and Kremer Pigment in Germany in their respective catalogs. Comparison is made easy by looking at the American Catalog and the International Catalogue online http://www.kremer-pigmente.com/englisch/homee.htm. While the stock differs slightly, the prices may vary significantly.

If you need to order a larger shipment, you might save money by ordering directly from the “pigment mill” in Germany. You can do so through the International Catalogue.

For example, I asked the New York office for availability and price of the “Painter’s colour assortment” (of pigments) which was listed in the international catalog. Their answer was refreshingly candid. Products can be shipped from Germany directly to consumers. They may even end up being cheaper than merchandise sold from the NY office due to the import tax added for retailers.

In this case ordering from Europe saved $130 (283Euro - equivalent to $250, instead of $380 if ordered from NY, shipping cost included in both cases). I decided that the substantial savings justified the inconvenience that the jars were labeled in German.

A request to get all available product information (specifications MSDS, labels) in English resulted in receiving some (but not all) MSDS sheets as attachment via email.

Note that small orders might not save any money due to the relatively high postage charged for shipments overseas (in this case $78).


Painter’s colour assortment - from the Baroque to the present (#14000 in International Catalogue 2001/2002) is compiled of a total of 30 classical pigments in 190 ml glass jars: 10000 Smalt, 10300 Malachite, 42000 Vermillion, 40810 Bohemian green earth, 43230 Praesodym yellow, 40220 Italian gold ochre, 40510 Venetian red, 40400 Italian raw sienna, 40440 Pompei red, 40630 Raw umber greenish, 40610 Raw umber from Cyprus, 40720 Burnt umber from Cyprus, 40280 Amberg yellow, 40241 Fawn ochre, 40231 Brown ochre, 48700 Caput mortuum reddish e 48750 violet brown, 44100 Cobalt green, 45700 Cobalt blue e 45730 Cobalt cerulean blue, 44250 Viridian green, 23610 Alizarine crimson dark, 47000 Vine black, 47100 Bone black, 46310 Zinc white, 47800 Beech charcoal, 45010 Ultramarine blue, 42600 Ultramarine red, 45200 Milori blue. The glass jars are either full or contain 100 g of pigment.

New Silica Gel Product

Art Preservation Services has developed a new form of silica gel, Rhapid Gel, for the passive control of relative humidity in museum exhibition and storage cases. Due to its exceptional moisture buffering characteristics in the mid RH range (40-60%), it is much more efficient than any other silica gel product for museum applications.

Rhapid Gel consists of tiny silica gel beads imbedded within a 1/8-inch thick porous polyester sheet, containing a 1/4-pound of gel per square foot of material. One square foot will condition up to 2 cubic feet of case volume in normal applications. The sheet can be cut easily with a utility knife or scissors. It is available either in 1 square foot sheets, or up to a 3-foot width, cut to the length of the user’s specification.

The material has an enormous surface area ratio, resulting in the fastest response time to changes in relative humidity among all high performance silica gels. For large case volumes, gel sheets can be stacked on top of one another without an air gap without any loss in efficiency within the depth of the stack.

The rapid response time gives users the capacity to re-utilize and re-condition the gel as needed. When placed in a container at the target relative humidity, it will fully equilibrate in two days time.

Alternatively, the silica gel sheet can be re-conditioned within the exhibition case. To increase relative humidity a damp wicking pad (such as those sold for residential evaporative humidifiers) can be placed in the case; to dehumidify add dry gel to the case, Because of the extended surface area of the Rhapid Gel sheet the humidity will gradually increase or decrease to target level, then remove the sponge or dry gel.

Due to the polyester matrix it is not recommended that people attempt to lower the humidity of the gel sheet by heating the structure in an oven or microwave.

Price: $10 per square foot. Ask for bulk quantity pricing. Art Preservation Services, 315 East 89th Street, New York, NY 10128. (212) 722-6300

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