PRO Sorb™ Humidity Control Systems
PROSorb™ is a new silica gel ideally suited to stabilize relative humidity inside museum display cases and storage cabinets. The ideal level of humidity for most museum display cases and storage cabinets is a level between 40 and 60% RH (Relative Humidity). PROSorb™ has a unique and exceptional absorption capacity within the 40–60% RH range. It is able to maintain a stable RH within narrow margins through its ability to both absorb and desorb water vapour; and is provided preconditioned to your desired humidity level. PROSorb™ also has a longer life span than other silica gels. Available as beads, full and half size cassettes.
Orange to dark green (when saturated) Silica Gel beads have a more obvious colour change than previously available for improved application in the display environment. Impregnated with an organic indicator (0.2% methyl violet) they are also nonhazardous.
Humidity Indicator Cards
Small, inexpensive and easily portable cards for giving approximate humidity readings. The cards are made from a Cobalt Chloride impregnated blotter divided into nine sections which exhibit various colours from blue through lavender to pink. The position of the lavender section indicates the relative humidity of the surrounding air. These can be used with ESCAL and PTS Bags as a long-term check against punctures and the ingress of moisture.
Dancheck Film Indicators
For monitoring the condition of acetate and nitrate film.
Film Archives throughout the world are fighting against time in a desperate attempt to preserve their collections. In the first half of the 20th Century nitrate film became explosive and now colour fading and “Vinegar Syndrome” are problems for acetate films.
The Danchek pH Indicator Strip is a piece of dyed filter paper, 10 x 40 mm. It is a very sensitive indicator and will sense “Vinegar Syndrome” when in contact with film. The colour is blue when fresh in the pouch, changing to pale yellow when exposed to an acid environment.
You will find a small bag in the pouch filled with silica doped with a strong alkaline to preserve the colour until needed and it is important to squeeze all the air from the pouch each time the indicators are used. Danchek Ph Monitor Window fits into the side of a film can or box and monitors the atmosphere within for any signs of acetic acid.
The Danchek Acetate Monitor can sense degrading films long before vinegar is smelt. If the Danchek Monitor shows light green – pH4.6 the film has probably reached the autocatalytic point and duplication of the film should be considered. The monitors are light sensitive and should be treated with care. Keep them in a bag in the dark until needed.
Method: Place the filter paper on the film (with gloves) and start the stopwatch. The strip test takes 2 hours and is a very accurate way of testing a film. Tests are performed at room temperature. If the colour changes to olive green you have reached the critical autocatalytic point, which is the point when you should consider separating the film from the rest of the collection and schedule the film’s duplication. If the indicator strip has not reacted within 24 hours there is nothing critically wrong and the film may be stored in the vault. Do not leave the indicator in the open air because it will fade within 24 hours.
Danchek Monitors clip into an 11mm hole for which a special film can punch can be supplied.
Danchek Monitors could also be used in Boxes and Storage Drawers by drilling an 11mm hole.