Nikon Labophot - Page 24

Failures
Causes
)
Actions
No sharp
• Out of focus
) • For preventing external vibration. use vibration-
picture
(Especially with high
proof table or rigid desk.
obtained
power objective and
• Select a place free from vibrations. such as caused
long-exposure)
by traffic. passers-by or motors etc.
• Momentary vibration-. Using NO fi Iters or others. elongate exposure time
(for color film. to 1/4 -1/15 sec.)• Lower the voltage. and elongate exposure time (for
black·and·white film).Note. however. for color film. that lowering of
color temperature and change of spectral character-
istics will be unavoidable.
• Incorrect thickness----+. Use a standard coverglass of 0.17mm in thickness.
of coverglass
(No.1 %)
(Especially. when
• Use objective With coverglass thickness compensa-
using large N.A. and
tion ring.
high power objective)
• Using dry objectives---+. Use no·coverglass type objective.
for smear preparations
• If other objectives are to be used. place a coverglass
on the specimen.
Fogging of
• Grease. dust or dirt----+. Clean the front of objective thoroughly. top surface
image
on optical surfaces
of projection lens. specimen. photographic lens.
condenser lens. field lens. etc.
Illuminated
• Condenser not
). Centering (Refer to P. 10)
image not
centered
uniformly
(This shows up
more conspicuously
in photography than
in observation)
Insufficient
• Aperture diaphragm---+. Generally. good resu Its wi II be achieved with
image
opened too large
aperture stopped down to 70 - 80% of N.A. of the
contrast
objective being used. (Refer to P. 10)
• Incorrect use of
). In metallurgical. interference. polarizing or phase
fi Iter
contrast microscopy. use of a green fi Iter or mono-
chromatic interference filter (e.g. peak wavelength= 546nm. half-value range = 30 nm) will increase
contrast.
• When contrast is to be increased for a part stained
with a particular color. use a filter whose color iscomplementary to the stain color (for black-and-
white film).
• Inadequate use of~. Stop down field diaphragm to a diameter slightly
field diaphragm
larger than the diagonal of picture frame.
(Refer to P. 16)
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