[3dem] amplitude contrast valuesHi,
David Gene Morgan
dagmorga at indiana.edu
Mon Jul 21 10:02:23 PDT 2014
Hi,
I'm trying to do some automated defocus determination (initially trying
Niko's ctffind3 program) and would like some input on appropriate
amplitude contrast values for various types of samples. I know that ice
embedded images usually are said to have an amplitude contrast of 0.07
to 0.1. I also know that with protein/nucleic acid complexes in ice,
amplitude contrast may need to be set a bit higher (say to as much as
0.15 for some data I worked on awhile ago).
But I don't have any sort of feeling for appropriate values of
amp;itude contrast for different sorts of negative stains (either cryo
negative stain or standard negative stain). It should be "high," but I
don't know how high might be appropriate.
If anyone has either some practical or theoretical insight into this,
I'd appreciate some suggestions. Also, does anyone know about an
appropriate amplitude contrast for a standard Au/Pd waffle grid?
Thanks in advance for all your help.
--
David Gene Morgan
Electron Microscopy Center
047D Simon Hall
IU Bloomington
812 856 1457 (office)
812 856 3221 (3200)
http://bio.indiana.edu/~cryo
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