Part 1 of this series, in the August '94 issue of this newsletter, contained an overview of digital imaging for TEM. The key point was that digital imaging systems are getting better and costing less. This article contains a brief summary of the pro's and con's of digital imaging for TEM.

Although different laboratories have different situations, there are common issues that all can consider when evaluating the value of a digital imaging system for TEM.

Information Density: As things stand today, atypical 1024 pixel by 1024 pixel digital imaging system cannot compare with film! Typical film used for EM can display feature sizes as small as 10 μm. This is like having a film negative made up of 10,400 pixels by 7,800 pixels. Put this way it's tough to see how a factor of between 7 and 10 can be ignored.