Photography

35-mm Black and White Negatives

  • Under appropriate light conditions (for most 35-mm films, this is total darkness)
  • Remove film from cassette. For disposable cassette, use can opener to remove one end.
  • For reusable cassette, bang extended end on counter.
  • Unwind film being careful to touch only edges.
  • Tear or cut off tabbed end if desired. Roll film onto reel.
  • Place reel in tank.
  • Place cover on tank.
  • Turn on lights.
  • Follow directions for dilution of developer and time and temperature of development recommended for film.
  • The small developing tank holds about 500 ml.
  • Agitate every 30 sec.
  • Empty developer by inverting tank without removing lid.
  • Rinse 30 sec in running water without removing lid.
  • Fix in Kodak Fixer or Rapid Fix for time recommended for film.
  • Remove cover of tank and empty fixing solution.
  • Wash 20-30 min in running water. Dip in Photo-Flo.
  • Hang and place weight on free end.
  • Dry overnight.

TEM Negatives

Solutions

  • Developer: 1 part D-19 stock 2 parts water
  • Fixer: full strength
  • Photo-Flo: 1 capful in container of water

Procedure

  • 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.

SEM Negatives

  • 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.

Prints

Solutions

  • Developer: 1 part stock Dektol 2 parts water
  • Fixer: full strength

Preparation

  • 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.

Exposure

  • 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.

Development

  • 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.
  • Dry

Magnification

  • 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

  • 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.

Leaving darkroom

  • 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.