High-quality virus images obtained by transmission electron microscopy and charge coupled device digital camera technology

The introduction of digital cameras has led to the publication of numerous virus electron micrographs of low magnification, poor contrast, and low resolution. Described herein is the methodology for obtaining highly contrasted virus images in the magnification range of approximately 250,000–300,000×. Based on recent advances in charged couple device (CCD) digital camera technology, methodology is described for optimal imaging parameters for using CCD cameras mounted in side- and bottom-mount position of electron microscopes and the recommendation of higher accelerating voltages, larger objective apertures, and small spot size. The authors are concerned with the principles of image formation and modulation, advocate a better use of imaging software to improve image quality, and recommend either pre- or post-acquisition adjustment for distributing pixel intensities of compressed histograms over the entire range of tonal values.