A Simple Method for obtaining Perforated Supporting Membranes for Electron Microscopy
Journal/Book: Reprinted from Nature Vol. 186 No. 4718 p. 104 only April 2 1960. 1960;
Abstract: Laboratory of Electron Optics Czechoslovak Academy of Sciences Brno Supporting membranes with holes are usually used for testing the axial astigmatism of the objective lens in electron microscopy. In the case of specimens which are difficult to focus they facilitate the focusing. Supporting membranes with a large percentage of open area are of great advantage for mounting thin sections because the gain in contrast is considerable1. It applies also to specimens for testing the resolving power of the electron microscope or high-resolution work when a very thin film of collodion can be mounted on these perforated membranes2. The holes will then enable not only the focusing but also a continuous control of the axial astigmatism. Several methods for obtaining holes in supporting membranes have been described3-5. Mostly "Formvar" film is used; but to obtain reproducible results the methods are relatively complicated. We have developed a simple method for obtaining holes in collodion films. This method does not differ from the others in principle as it is based on the introduction of minute water droplets into the film; but it does not require any special equipment and makes it possible to prepare the membranes or nets very quickly and in a reproducible way. . . .