Dry development of diazotype material - uses controlled drip of developer to regulate speed of flow through developing chamber

摘要

In appts. for the dry development of diazotype material, ammonia is added drop by drop at one end of the development chamber. A flow of between 3 and 15 cm3 per minute is suitable for a total volume of ammoniacal solution of 15-20 cm3. The overflow is situated at the other end of the container so that the liquid crosses the container at a speed of between 30 and 130 cm per minute. This ensures that the solution always has a sufficient concentration to produce satisfactory development of the diazotype material. The heating resistance and thermostat are chosen for a surface of 0.0125 m2 so that the solution varies only between 19 and 28 degrees baume in relative density.