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SchoolTrack 4 · Film

LESSON · THE DARKROOM

Developer, stop, fixer

How a black-and-white roll becomes negatives in a kitchen: three chemicals, one tank, about half an hour.

STEP 01

Developer

Turns the hidden image into a visible one: it reduces the silver halides that saw light into black metallic silver.

ALKALINE · TIMED TO THE MINUTE

STEP 02

Stop bath

An acid bath, usually about 2% acetic acid, that cancels the alkaline developer and halts development at once.

WEAK ACID · 30–60 S

STEP 03

Fixer

Removes the silver halides that never saw light, so the film stops reacting and can face daylight.

THIOSULFATE · THEN WASH

Step by step

BLACK-AND-WHITE · MOST CHARTS ARE TIMED AT 20 °C

  1. 01In the darkLoad the film onto the reel inside a changing bag or a dark room, then close the tank. From here the lights can be on.
  2. 02DeveloperPour in at the chart's temperature, start the timer, invert the tank gently at set intervals.
  3. 03StopPour out the developer, pour in the stop bath, agitate for under a minute.
  4. 04FixerPour in the fixer and agitate for the time on its bottle. Fixer can be reused.
  5. 05WashRun water through the tank until the fixer is gone, then a drop of wetting agent.
  6. 06DryHang the strip in a dust-free room with a clip at the bottom. Cut and sleeve when dry.

WHAT YOU NEED

The home kit

Tank and reels

Changing bag

Thermometer

Measuring jugs

Timer

Drying clips

Work with gloves and air, keep the chemicals out of the kitchen cups, and follow the safety sheet and times printed on your developer and fixer.