Professional PK RA-4 (RA-4 standard process at 35 degrees C)
We suggest you use this kit with equipment with a thermostatically controlled processing temperature, set at 35 degrees C.
Development can be carried out in both roller and standard tank processors (e.g. Jobo processors).
The Professional PK RA-4 pack contains colour developer Part 1 (250 ml) and Part 2 (250 ml) bleach fixing bath, Part 1 and 2 (500 ml each) to make up 5 litres of working solutions. You can also make part amounts up.
The main advantage of this process is the short processing time. This dramatically reduces the time spent waiting for filter and exposure samples.
In full, closed bottles the baths keep for about three months and roughly 4 - 6 weeks if the solutions are partly used. Up to 3m2 of paper can be developed per litre of working solution if you use drums for processing. That means sixty 8 x 10-inch cm sheets!
If developing in processors, in addition to standard processing (45 seconds at 35 degrees C), a shorter process can also be used, with a 35 second development time at 38 degrees C, if a pre-wash is included before development and a stop bath is put in between the colour developer and the bleach fixing bath.
Choosing 38 degrees C for the process temperature, with processors such as Jobo CPP3, means that other 38 degrees C processes, 0-41 and the E-6 three-bath process can also be used without having to change the temperature of the water jacket.
Because of the high output when developing in drums, it is useful to change the solutions in stages. Replace one-third of the working solution with fresh solution after each procedure.
Example: use 90 ml of working solution for two 17 x 24 cm sheets. Collect the solution used after each stage. Use 60 ml of this with 30 ml of fresh solution for the next step and throw the rest away. Repeat as often as you like. The processing times are the same; only the bleach fixing is extended by 15 seconds.
If the prints have above-average black areas (e.g. with low-key photographs), the chemicals in the baths are stronger than usual. In this case, we recommend abundant replenisher and extending the development and bleach fixing time by 1 minute each.
It is possible to make up part amounts from the concentrates and once opened; these concentrates will keep for about six months if protected from oxidation. Using Tetenal's Protectan helps in this respect.
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The specific replenishment rates for this kit for use with a Nova are as follows:
The replenishment rates for the Nova tanks are 10cc per 8 x 10-inch print, and after 100cc has been replenished (per 800sq inches or equivalent), you should be top up with plain water to the working level if needed.
Do not replenish with more developer as this will reduce the working life of the developer because there is 'starter' in all the kit. This replenishment also applies to the Blix bath.
Capacity is approximately 15 square metres for 5 litres of working solution.