Improved record keeping and photography of silver-stained two-dimensional electrophoretograms by way of "XRD images".

Kodak X-Ray Duplication film provides a relatively simple and inexpensive medium for producing full-size positive-image transparencies ("XRD images") from silver-stained two-dimensional polyacrylamide gel electrophoretograms. In these XRD images, the spot or band pattern of a polychromatic silver-stained gel is represented as black against a clear background, regardless of the color of the spot in the gel itself. Thus, XRD images may be overlapped with transillumination for visual gel-to-gel comparisons, may be easily subjected to scanning densitometry, and may have the exposure adjusted to provide the proper background for black-and-white photography. I describe here the details of the XRD method and the design of a new apparatus for producing XRD images in a wet-gel "contact-print" format, which improves the method.