Electron Projections of Thin vs Thick Sections
Electron images are projections through plastic-embedded specimens. Sections of conventional thickness (@ 70-100 nm) are essentially two dimensional and structure in the third dimensional is often erroneously extrapolated. This can be remedied by reconstruction of serial sections. However, since each section is a projection, they must be thin enough (ultrathin-25 nm) to adequately sample the entire volume or continuity of structure may be missed. An alternative means of visualizing thick sections is by stereoviewing the section viewed from a 7 degree tilt differential . When the two stereopairs are viewed by the left and right eye separately, three dimensionality of the volume is perceived. The anaglyph method of doing this requires red-cyan glasses.