RA4 process in a Durst rcp40 VSN

[borgunto]

Hi everybody!
I've just found for a few euros an used Durst RCP 40 VSN (variable speed) processor. I'd like to use it for RA4 process. I am aware that this machine was designed to work for the old – and slower - Ep2 process, but, since it has variable speed, I was told it was possible to process RA4 too...

Well, if I I modify the speed of the machine in order to obtain a developing time of 45 seconds, as a result, the blix time goes to something like 30 seconds (the three tanks of this processor are not of the same size)...

What is it better to do?:

1) to leave the blix at 30 sec (with an acetic acid stop bath in the second tank)?
2) slowing the machine, in order to obtain 45 sec in the blix (of course, I'd have, as a consequence, a slower developing time and I should compensate with a lower temperature)?
3) to fill the second and the third tank with blix?
Has anybody an experience with whis kind of machine and RA4?
Thank you for your kindness!
Damiano

 

[Mike Wilde]

RCP20 here

Mine was re -geared for RA-4. It is a fixed speed machine. It now runs 1' tank 1 and 3. tank 2 runs stop. The temperature is adjusted to suit the time/ temp to get full blacks, but no fogging in whites from over developing. The I scavenged the pumps and heaters for a water bath tempering solution for e-6, and now run my ra-4 in a fijimoto cp-31, variable speed set for 45' for each of three eqaul sized tanks.

 

[PHOTOTONE]

I had an RA40 (still have it, but not in use). The Developer and Blix racks are exactly the same length, so the time in each solution should be identical. The Stop rack is of course smaller. If you set your variable speed to give a 45 second develop time, your blix should also time out to 45 seconds. HOWEVER...the RA40 machines do not have a spray-bar in the inlet of the developing rack to spray developer vigorously on the paper, thus you MAY find that you need to extend the overall time of the machine to achieve adequate developing. To get even development with a 45 second develop time, the developer in later machines was vigorously sprayed (under the solution level) directly up onto the paper as it entered the developer rack. This is much more vigorous movement than the slow recerculation given with the RA-40 set-up.

 

[borgunto]

I had an RA40 (still have it, but not in use). The Developer and Blix racks are exactly the same length, so the time in each solution should be identical.

ciao Phototone and thank you! unfortunately mine - model RCP VSN - has different dev and blix racks...

 

[Chan Tran]

The developer time must be right for the temperture, so I would not mess with it. The Blix time longer than standard isn't much a problem but in this case shorter and I have found problems with short blix time.

 

[stefan4u]

High Damiano et al !!

Just remarked that You posted your question here too, so lets spread information a bit
Taken from http://photo.net/film-and-processing-forum/00REc2

...

The VSN Series is indeed a bit changed to obtain better Dev. Blix time ratio for EP-2 Process, that's why the Blix rack is smaller. There should be an option for mounting a wash and dry unit too, nice animal...

Back to your question, the older rcp 40 VS does have two independent thermostats for Dev and Blix. If this is still given at the RCP40 VSN I would increase the blix temp to something about 40°C. If there is only one common thermostat (which is possible, different processing needs are already considered through changed racks) I would try to prolong the Dev. time slightly (~10sec.) and use a more concentrated Blix ...


...
A Day later…

Nice to hear that your machine have two independent thermostats. Everything will be fine if you take 35°C for the developer (at 45 seconds dev. time) and 40 till 42°C for the blix (assuming that you use "regular" chemistry, not the room temperature stuff)

By the way, do you have a decent thermometer? The temperatures shown on the thermostats knob are not necessary correct.

The stop bath was necessary for EP-2 to prevent overdeveloping, staining and stripes during slow transport from developer to blix. It's not mandatory in RA4 but a benefit. Blix will keep longer and you probably get better whites. I always used a 5% acetic acid stop bath in my older (non "VSN") RCP, the only drawback is it's smell...

If you don’t replenish your chemicals it will be good to increase the temperatures for about 0.5°C after each square meter of processed paper to compensate activity loss. You can’t do this without limits, but it will help to get constant results over the lifespan of the chemicals. This is something you have to work out mostly for yourself by “try and error” because it depends on used chemical brand, grade of exhaustion and storage time / conditions…

Regards from Germany,
Stefan

 

[borgunto]

Thank you Stefan, thank you everybody:
finally yesterday I could do my first print with the RCP 40 VSN..

As suggested by Stefan I increased the temp of the blix to 40 C° and everything worked fine: I am very pleased with my first color prints!!

Just another question: I'm going to use the machine tomorrow or on Saturday, so I left the chemicals in the processor (lazybone...): is it better to drain the chemicals, store them and wash the machine every time?

Thank you for your help!
Damiano

 

[stefan4u]

Congratulations

Nice to hear that your processor is in use! The Durst RCP VSN series definitely deserves to be used, nice machines...

It would be better to drain the chemicals and rinse the tanks, this is inconvenient, I know. But this is no comparison to the inconvenience to clean all racks / tanks from developer residues, if stored too long in the machine. Before this happens you will have problems with oxidation products, grabbing for dye couplers and leading to pink whites (depends on chemicals and paper). It will be no problem leaving the chemicals a day or two in the machine, but for longer times the developer is stored better bottled, in a cool place. This is for sure a bit “overcorrect”, but I’ve learned my lesson…

My current developing machine, a Thermaphot ACP 305 was in semi-professional use till it broke. Repairing the unit was not that difficult, but oh boy, cleaning all the racks took me days (probably more a week)

Regards from Germany,
Stefan

 

[PHOTOTONE]

The developer will "tar" up if it sits, and the Blix will decompose and leave huge amount of whitish sediment. Best to drain and rinse everything up.

 

[Mike Wilde]

I second the comment to store out of ther machine

Mine came to me drained but never rinsed. Never have I meen more intimate with rubber gloves anddilute toilet bowl cleaner, and then scrub, scrub, scrub, rinse, and then scrub agian.

Once I left blix in the tank, and it started to sufate out - little silver bits started to flake out as well. That was a close one; now I drain and store unless I know I am back at it the next day. If that is the case, I pull and rinse my racks, and lay saran plastic wrap over the tops of the tanks.

 

[borgunto]

When should I replenish?

Sorry, another question...
when would it be better to replenish the chemicals:?
a) at the end of a printing session, just after draining and storing the chemicals in their canister?
b) at the beginning of a new printing session, pouring the replenishers in the processor racks?

thank you all!