35-mm Black and White Negatives
- Developer: 1 part D-19 stock 2 parts water
- Fixer: full strength
- Photo-Flo: 1 capful in container of water
- Turn on water and adjust flow until level is just below top of overflow tube of nitrogen burst system.
- Wait until temperature reaches 20°C.
- Remove floating lids from developer and fixer.
- Place in sink.
- Turn on nitrogen tank with knob on top of tank. Do not turn knob on regulator.
- Turn switches on control unit to gas and burst.
- Place negatives in holder making sure negatives are separated.
- Place negatives in developer for 4 min.
- Rinse negatives by dipping in water 30 sec.
- Place in fixer for 8 min.
- Wash in running water (between developing tanks in nitrogen burst system or in separate container under faucet) for 20 min.
- Dip in Photo-Flo. Dry Store negatives in glassine envelopes.
- Place negatives in bucket and rinse with slowly running water until bucket is filled or ready to process.
- Rinse last negative for about 10 min.
- Place in bucket of 18% sodium sulfite for 15 min.
- Rinse in cold water for 20 min. Dip in bucket of Photo-Flo.
- Hang negatives on line to dry.
- Developer: 1 part stock Dektol 2 parts water
- Fixer: full strength
- Turn on water and wait until temperature reaches 20°C.
- Place solutions in trays: diluted Dektol, water, fixer, and large tray with water
- Place hose from faucet in final tray of water.
- Set condenser of enlarger for size of negative: 3 1/4 x 4 for TEM, 4 x 5 for SEM
- If necessary, place appropriate lens in enlarger.
- If lens is dusty, clean with lens paper.
- Place negative emulsion side down in negative carrier.
- If negative is dusty, remove dust with compressed air or soft brush.
- Place negative carrier in enlarger.
- Set sliding bars and paper stops on easel to give desired size of print and margins of desired width.
- Turn switch on timer to F (focus).
- Place sheet of exposed photographic paper emulsion side down in easel.
- Adjust enlargement to desired amount with switch on side of enlarger.
- Focus negative using magnifier.
- Position easel to include desired area of negative.
- Adjust light intensity with F-stop ring on lens.
- Set desired time of exposure on timer.
- Turn switch on timer to T (time).
- Replace paper in easel with unexposed Kodabrome II RC photographic paper emulsion (shiny) side up.OPEN BOX ONLY UNDER SAFELIGHTS.
- Press button on timer to start exposure.
- When exposure is complete, remove paper from easel.
- Immerse paper in developer quickly and completely.
- Print should remain in developer until it begins to look too dark. The print will appear lighter under white light.
- Transfer to water: 10-15 sec
- Transfer to fixer: 2 min
- Transfer to large tray with running water: 4 min
- Remove excess water by pulling squeegee across surface of print lightly.
- Place prints face up on paper or prop on side.
- Enlargement of negative should be determined before changing enlargement setting.
- Place clear plastic ruler in negative holder.
- Print ruler or measure image with second ruler and record measurement.
- Magnification factor = size in image/size of object Example: if projected image of 1 cm on ruler measures 3.5 cm, magnification factor of negative = 3.5
- Final magnification of micrograph = magnification of negative x magnification factor for print.
- Contrast may be increased by using a higher grade (number) paper or reducing exposure time and/or light intensity and increasing development time.
- Contrast may be decreased by using a lower grade (number) paper, increasing exposure time and/or light intensity and reducing development time, or placing negative in the enlarger with the emulsion side up.
- Place negative holder in drawer.
- Place box(es) of photographic paper in correctly-labeled drawers.
- Check fixer with drop of Hypocheck. If fixer is good, the drop will remain clear.
- If fixer is exhausted, drop will turn milky.
- If fixer is good, return fixer to storage bottle.
- If fixer is exhausted, pour out.
- Rinse tray thoroughly.
- Pour out developer and rinse tray thoroughly.
- Pour out water in remaining trays.
- Wipe all surfaces with damp sponge. MAKE SURE ALL SURFACES ARE CLEAN. DEVELOPER AND FIXER WILL FORM A CRYSTALLINE FILM AND WHITE POWDER, RESPECTIVELY, IF NOT REMOVED.
- Prop trays on side of sink to dry. Turn off safe lights.