For starters, this is how it looks:


At the far edge of the plastic 25L (5+ gallon) bowl is the immersion heater with built in thermostat, at the left end the smallish circulation pump – both bough at an hobbyist aquarium shop – total cost less than 50€. Visible is also the cheap digital thermometer I use.

The remainder are numbered 500ml PET bottles and caps with mixed Digibase C41-kit chemicals, plus the rightmost bottle – plain water. The rubber bands around the bottle necks allows to have them lie down in the water, attached to a clothes peg on the edge of the bowl.

This C41-kit comes with time descriptions for temperatures from 25 to 45°C;

  1. I have found 15L water in this bowl be just under the limit where the bottles still stand.
    As the dev-tank has a bit bigger bottom area it doesn’t stay upright – I have to remove some water before putting it down into the bowl.
  2. First make sure the water bath temperature is constant, at the the point you have chosen (read out from instructions).
  3. Read out the times from the instructions. I have chosen to sum up the times; so that I have “time points” where to switch liquids. I jot down these on a piece of paper before starting – see step 6 to understand why.
  4.  Load the film onto the reels in the dev-tank, using either your darkroom-bag or pure “darkroom” (whatever way you may come up with).
  5. Prepare for drying the film – rope and clothes pegs are the basic equipment, a place in a shower is very good.
  6. Start a timer, I use an egg-clock counting upward – therefore the summed up times in 2)
  7. Immediately after, start by pouring in the temperature adjusting water bath (rightmost bottle).
  8. Place the tank in the water bath, slowly remove excess water to make it stand steadily upright.
  9. Agitate! (Removes water bubbles for a starter)
  10. Leave the water in the tank, at least for the prescribed time.
  11. As there are 20-30 seconds left of the time; pour out the liquid, into the correct container for later liquids (do NOT mix caps or bottles)…
  12. Have the tank turned upside down to let it drip off a bit, turn it back as you still have enough time to prepare for the next step…
  13. At the prescribed time point, pour in the next liquid.
  14. Seal up container and wash up after the used liquid.
  15. Agitate the tank as prescribed in the instructions.
  16. For each liquid, repeat from step 11 .
  17. As the last liquid is in; prepare to hang the film to dry – run HOT water in the shower until there is steam in the room
  18. As the last liquid has been poured out; hang the film to dry,
  19. Check that there is no dust or bubbles on the film surface. If there is, make sure to have a minuscule amount of surfactant in water to spray with
  20. Allow to dry at least one hour and completely tack free, better yet 24h.

Analyzing C41 negative film development: