A Replacement for Kodak Industrex 620 Paper used in Seed Analysis

Bob Karrfalt

Director, National Tree Seed Laboratory

USDA Forest Service

Introduction

Kodak Industrex x-ray paper (Industrex 600 and 620) was widely used for seed analysis in seed conditioning plants and seed labs for about 3 decades. This x-ray paper allowed for quick (2 to 5 minutes) accurate radiographic examination of seeds to guide seed conditioning and testing decisions. This paper is no longer available. Some options for replacing it are: Polaroid film, digital camera, or x-ray film. Polaroid has also been used for x-ray analysis for decades. However, it is relatively expensive, has a short shelf life, has an image quality much poorer than the paper did, and is only 4x5 inches which is too small to do many larger seeds at one time. Digital also has a small image, and at the moment is expensive. The cost of a digital camera for a cabinet x-ray system, such as the Faxitron MX20, is equal to the cost of the x-ray machine or about $25,000. Researching a film replacement for USDA Forest Service nurseries identified the following film and associated processing chemicals and film processor. Kodak products were researched as these were available to USDA agencies from a government contract with favorable pricing. The USDA Forest Service, therefore, does not endorse the following items. They are simply recognized as suitable for seed analysis. Comparable products are most likely available from other film manufacturers and may be more comparable in cost on the open market.

Items Identified as Suitable for Seed Analysis Work

Film processor: Kodak X-OMAT 1000A Processor CAT No. 879 0 198

Film: Kodak X-OMAT BT film 8 x 10 inches CAT No. 866 9400

Developer: Kodak X-OMAT EX II

Developer and Replenisher: CAT No. 113 5433

Fixer: Kodak X-OMAT LO

Fixer and Replenisher: CAT No.886 8804

Discussion

Film processor

The Kodak X-OMAT 1000A Processor will process a film about as fast as the paper processor did a sheet of paper and will produce a dry developed film ready for examination. This processor will have to be connected to a water line. It only consumes water when it is developing a film. There is another small processor made by Kodak, but it uses 0.5 liter more water per minute and doesn't appear to have an internal drier.

Film

The film was tested with Abies grandis, Quercus rubra, Rubus allegheniensis, Pinus palustris, and Prunus serotina. The x-ray machine settings (kVp and exposure time) used for this film were comparable to those used for the paper. Therefore, a transition to film should go smoothly. All test films were developed manually in plastic trays and held under the water tap for 10 to 15 seconds to rinse both sides of the film. Air drying resulted in no curling of the film. Manual processing would only be suitable for small quantities of film as examination of the films is delayed until they are air dried. Neither is air drying convenient because it would require a long drying line when doing many exposures at one time. This film is available in 8x10 inch sheets that can be filed everywhere we have filed the paper radiographics. It is made to be used in the automatic processors. The film radiographs will be good for 100 years while the paper was good for maybe a year unless treated with fixer. Image quality will be better with film than it was with paper. This is bulk film and will need to be loaded into cassettes as was the paper. Ready pack films are available but at much higher costs, and are a different type. A view box is required to examine the developed film, but this can easily be made or purchased. A view box is simply a box with a light inside it and a translucent top to put the film on for examination. This film is manufactured for general radiographic medical purposes. There are Industrex films, but they take 4 minutes to process manually and 6 to 12 minutes to process with automatic processors. This is not quick enough for seed analysis.

Developer and fixer

This could be the best part of loosing Industrex 620 paper. These are formulated to significantly reduce the odor and acid fumes. The developer is made without acetic acid and the fixer is formulated to reduce acetic acid and sulfur dioxide emissions. The processor holds one gallon of each. Therefore, one minimum order of concentrate will recharge the developer 10 times. A one liter graduated cylinder, a 100 ml graduated cylinder, and a 4 liter beaker will be needed to mix the fixer and developer concentrate with water and their replenishers.

Technical data

More detailed technical info can be viewed on the web following these links. http://www.kodak.com select Medical and Dental, select Medical Solutions, select Medical Films. On this page are links to descriptions of the films, the chemicals and processors.