DK-20

About the Developer

DK-20 is an ultra-fine-grain metol developer for photographic film, well-suited for processing light-sensitive photographic materials. Thanks to potassium thiocyanate (a silver solvent), it reduces grain size by approximately 25%, but reduces the film’s effective light sensitivity by about 30%.

Character

An ultra-fine-grain methol developer containing a silver solvent (potassium thiocyanate). It reduces the light sensitivity of photographic materials by approximately 30% and grain size by approximately 25%.

Best films

The source does not provide specific data on particular films; historically, it was intended for high-sensitivity roll film, where minimal grain is the most important factor, rather than maintaining full sensitivity.

How to Prepare and Use

1. 1Pour 500–600 ml of distilled water at 45–50°C into a container marked at 1 liter.
2. 2Dissolve the contents of the first (large) bag—sodium sulfite, borax, potassium bromide, and potassium thiocyanate—in it until all the lumps have completely dissolved.
3. 3In a separate container, dissolve 50–70 ml of the solution from the first container in 200–250 ml of water at 45–50°C, then add and dissolve the contents of the second (small) packet—metol.
4. 4Immediately combine the two solutions and let them cool.
5. 5At a temperature of 20°C, add distilled water until the level reaches the 1-liter mark.
6. 6Let the solution settle for 2–3 hours, then filter it through cotton wool.
7. 7Develop with fresh solution for 15–25 minutes at 20°C (for some films, the time may range from 14 to 31 minutes).