black & white processing & printing

film developing

Make sure the darkroom door is locked and that the safelight is off. Carefully load your film onto a developing reel in total darkness, place the reel in the developing tank and put the big black lid onto it. The development sequence for Kodak T-Max 100 is:
 

develop in Kodak D-76 (diluted 1:1)	13 min.
rinse in water	30 sec.
fix in Ilford Universal fixer (1:3)	5 min.
wash	20 min
rinse in Kodak Photo-flo (1:200)	30 sec.
hang up to dry	~30 min.

 
The chemicals must be at 20 degrees Celsius. Our D-76 is kept full strength and must be diluted for use. You will need 200 ml of working solution for each roll of 35mm film and 400 ml for each roll of 120 film. Pour each chemical smoothly and quickly with the tank tipped at about a 30 degree angle and then put the little lid on. Agitate by inversion for the first 30 seconds and then for an additional 5 seconds every 30 seconds for the rest of the developing time. The developer should be poured down the drain after use. Fill the tank with water and drain and then pour in the fixer. Again agitate every 30 seconds.

Return the fixer to its bottle after use. Wash the film in the washing cylinder for 20 min. and then rinse in Photo-flo solution. Be careful with the wet film because it picks up lint and scratches very easily. The film drying rack should not be used for storage so please take you film away within a day or so.

After checking with a magnifying glass and light box to see which negatives are worth printing put the film in the enlarger and focus carefully. Usually you should start with a Multigrade filter #2, depending on factors such as the histological stain, subject contrast and negative exposure. If the contrast needs adjustment then change the filter. Higher number filters give higher contrast, lower numbers give lower contrast. If you have to go to #4 or above then the exposure time must be doubled. The exposure must be determined by a teststrip.

Good prints usually have no area that is pure white (other than the margins themselves) and none that is dead black. Instead there should be a range from very dark to very light grey with a full range of tones in between. Good contrast in the final print is almost as important as correct exposure and sharpness.

Light microscope negatives should not be enlarged too much or they will look fuzzy. Four inches by five is usually a good size, unless they must be larger. The final magnification of prints from the light microscope should not be more than 1000 times the numerical aperture of the objective. Typical numerical apertures and maximum print magnifications are:

The magnification of the final print will be:
(objective) x (nosepiece factor) x (tube factor) x (projective) x (camera factor) x (enlargement)

Make a test strip with exposure zones of 1, 2, 4, 8 and 16 seconds and then follow this developing sequence: