OPT407: Electron Microscopy
Spring 2010
Final Project
Introduction
As a photographic lover, it is common to
take a camera with me to record what I see into rolls of
films.
Compare to
digital sensor, film is a classical choice for photographer to take
picture
with wonderful colors and enjoy the surprise after 36 times shutter
release.
How films record images has always been
very curious to me, so I decide to use
microscopy to see the film structure in this project.
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Sample preparation
The samples are made
from several kinds
of films which I used before. Basically, they are black & white
films and
color films.
They are cut by razor blade or ultramicrotome
in order to have a clear cutting to see
the cross section of films.
All the samples are coated
with gold by sputter coating to ensure
conductivity.
The TEM sample is prepared by ultramicrotome.
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Analysis
Methodology
Scanning
electron microscope analysis was done using a Zeiss
SUPRA40-VP model SEM and Transmission
Electron Microscope analysis was done by a FEI Tecnai F20 at
the Institute of Optics at the University of
Rochester.
In
SEM analysis, secondary electron detector (SE2), InLens detector and
backscatter electron
detector (BSD) were used to collect micrographs.
BSD
detector are specially used to find out the position of silver particle
in film layers. X-ray microanalysis was down using
an EDAX x-ray spectrometer for compositional analysis.
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Results
and Discussion
From
reference, the basic films structure is noticed.
figure
1. The color film cross section.
figure 2. The B&W film cross section.
By using SE detector, The color film cross section could be seen.
There are several different layers in the cross section.
Three record layer and base are clear and the interlayer could slightly
been seen.
The image in color films is formed by dye. The silver particles are
already been moved out in film processing, so there is nothing obvious
under BSD.
figure 3. color film cross section
figure 4. record layers
figure
5. colored
layers
figure 6. pore structure in record layers
figure 7. InLens
In B&W films, not like color film, it only have one record
layer. However, the image is formed by silver particle left in record
layer, it is easy to figure out the silver particle contained in
gelatin in emulsion layer.
figure 8. B&W film by SE2 and BSD combined
figure 9. B&W film silver particle in
gelatin.
figure 10. silver particle in B&W film.
figure 11. BSD micrograph: a layer of silver in B&W
film cross section.
figure 12.
B&W film silver
particle in gelatin by BSD.
figure 13. The
silver record layer is only a small region in the film.
figure 14. B&W film by SE2
and BSD combined (BSD more)
figure 15. B&W film SE2, BSD cross mix.
figure 16. By EDAX, the silver layer shows a clear Ag pick.
figure 17. Ag signal in silver layer
from x-ray mapping.
figure 18. Silver particle from TEM.
figure 19. silver particle from TEM 2.
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Conclusion
The
color film layers are very obvious from cross section cuted by ultramicrotome.
However, the bad
part is there
are no metal particles in color film layers, so the BSD micrograph
shows nothing interesting in color film.
In
B&W film, most of the structure is base. There is only a thin
region of silver in gelatin.
Using
BSD detector, other part of the film turn black and only left a
shinning silver layer.
By
combining BSD and SE micrograph, surface detail and
composition can both be seen in combined micrograph.
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References
Films &
Filters <http://www.geog.ucsb.edu/~jeff/115a/lectures/films_and_filters.html>
kodak
color film
<http://motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_education_kodak_color_films.pdf>
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Acknowledgments
I
would like to thank Brian McIntyre for his guidence, advise and help to
use SEM, TEM and ultramicrotome.
I
also want to thank Andreas Liapis for
his assistance about sample preparation.
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