MACO™ Electron Microscope Film
Processing
Developers and Developing Times
MACO EM and ES films can be developed in all commercially available developers. Electron micrography films will
preferably be developed in high-energy developers. We recommend LP-DOCUFINE HC and Kodak D-19, but
also Ilford ID-11 and Kodak D-76. The following developing times are for guidance, serving as starting
values for your own optimisation. Due to the specifics of processing, the end user may have to adapt
these values to meet specific needs.
|
Developer | Developing
time (min) |
|
LP-SUPERGRAIN 1+9 | 5 |
|
LP-DOCUFINE HC 1+7 | 4-5 |
|
Kodak D-19 1+2 | 4 |
Stop Bath
The stop bath primarily serves to neutralise any alkalinity retained by the film in order to prevent
a loss of fixing-bath activity due to increasing pH values. The following stop bath concentrates are
recommended. On the other hand, Kodak® fixer
should work just as well
|
Stop Bath | Time (min) |
|
LP-CITRIN 1+19 | 1 |
|
LP-CITRODUR 1+16 | 1 |
|
LP-ECOSTOP 1+7 | 1 |
Where a stop bath is not used, two intermediate washing cycles of 30 s each, at 20°C (68°F)
and permanent agitation, are recommended to avoid the carryover of developer into the fixing bath.
Fixing
For fixing MACO EM and EMS films we recommend LP-FIX SUPRA at a dilution of 1+7 to 1+9. This is a
modern high-performance fixing bath on the basis of ammonium thiosulphate. The necessary fixing time
can be found by determining the clearing time (fixing time = twice the clearing time). Where clearing
time is not determined, fixing for three minutes in fresh fixing bath at 20°C is recommended.
Washing
Ensure that the water-supply temperature is approximately 20°C. Washing for 5 min in running
water is then sufficient.
Wetting Agent
A final bath in demineralised, deionised, or distilled water (battery water) is recommended in order
to avoid drying marks caused by water hardness and to reduce static charges. Static charges will
cause the film to attract dust particles which will show as white spots on positive copies.
It is recommended to use LP-MASTERPROOF 1+200 to 1+100 for one minute, without agitation.
(This will avoid the formation of foam, see below. )
Overdosing wetting agents must be avoided. Wetting-agent solutions can only be re-used if several films
are processed in one session. Foam tends to stick to the film surface and will hardly run off. Therefore,
avoid foam formation when preparing wetting-agent solutions by adding the water slowly.
Kodak® Photo-Flo 200 Solution should work quite
nicely on both the MACO EM as well as the ES film.
Drying
Squeegeeing films is not advised as there is a great chance of scratching negatives. Following the
wetting-agent treatment, try to shake off as much of the surface water as possible. Then hang the film
to dry in a dust-free environment for several hours, e.g. over night. When drying films in a drying
cabinet, it is recommended not to activate the heating. Drying using a hairdryer is not recommended, as,
lacking a particle filter, hairdryers will tend to blow dust particles onto the wet, and still sticky
surface of the film. Particles adhering to the film like that are difficult to remove without afflicting
damage to the film.
Note #1:
After processing a more or less magenta to reddish tint appears on the film.
This slight haze has no influence on the photographic parameters and will
not manifest itself when a print is made from the negative. The reddish
tint will disappear within minutes under sunlight or after a short time
under daylight or UV light.
Note #2:
After processing a greyish haze can appear on the film. Reasons: The
distance to the safelight was less than 1.2 m or the safelight was
red/orange/yellow. Another reason could be that after the passing of years,
there can be some deterioration of the organic pigments that are used in the
making of the safelight filters and a new one should be obtained. To
improve results: Control the power/watts to the safelight, perhaps with a
dimmer switch and make certain that the distance is never less than 1.2 m.
Make sure the film developer is up to acceptable strength. If the slight
haze does not disappear also be using fresh photo chemistry, the
concentration should be increased respectively and the developing time
extended.
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Monday March 22, 2010
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