Newbie question for processing with CPE-2 Plus

Hi,

My CPE-2 Plus arrived today and was going to run my first roll of Tri-X 400 through it later on.

Can any users of the CPE or CPP offer advice on processing times and the issue of pre-rinsing. I believe I read somewhere (don't remember where) that if you do a 5 min pre-rinse at your process temp (20ºC) then you can use your normal hand agitation times as the film acetate layer, being wet, absorbs the developer slower, and more uniformly than otherwise such that this compensates for the constant agitation (rotation)... and that if you skip the pre-rinse then calculate on cutting development time 15% compared to "normal" (whatever your "normal" is using hand agitation).

Is this correct?

Regards,
Antonio

All I can say is that I do NOT 'pre-wet" and after analyzing exposure and times, have concluded that, with very few exceptions, "recommended" ISO indices and "recommended" developing times are *very close*. As I understand it, "pre-wetting" is supposed to insure uniformity of processing, but as for me, I could determine *no* difference with it or without.

I will use DRY "pre-temperaturing" to stabilize film temperature - a couple of minutes of tank rotation in the water bath before processing - but I've never really determined the necessity for that, either.

Your mileage my vary.

I do a "pre-wet" - a pre-tempering with water in.

I do that anyway; whether developing in tanks, trays, machines or buckets.

I used the Jobo recommended 5 minute pre-rinse and my standard development time when I started using my CPE-2+. Seems to work, and helps get rid of the anti-halation coating from Ilford Delta if you worry about that sort of thing If you have a Lift, it is little extra work.

Just run off a couple of comparison films if you are worried. There is plenty of scope for finessing your procedure once you have some examples of your own to compare. Anything I say is at best an approximation to your conditions. The nice thing about the Jobo is that it standardises a lot of the process.

I am (mainly) using mine for Delta 100 in 5x4 using FG-7 at 1:15 8.5 minutes, 21 C, EI 50. Exactly the same time as I use in tubes and tanks using one inversion every minute. So far, so good!

I use the 5 minute pre-wash and still find that I need to reduce my dev times by around 25%.
That isn't a suggestion. Many report that they use the normal time after a pre-wash. Nothing that you can do but test it in your own darkroom.

I am convinced that the pre-wash does help with producing more even development, though.

Thanks guys.

I ended up pre-rinsing 5 mins (all the purple anti-halation dye washed out!)

Then processed the Tri-X 400 @ 20ºC for 10 mins.

Stop: Ilfostop

Fix: Rapid Fixer

Ilfotol washaid.

= Negs look overdeveloped (thick), very dark highlight areas... either overexposed or overdeveloped. Will try 25% less development time next and see what that does.... The constant rotation of the drum has to have an effect on development, surely?

The machine sure does use a lot of water! Not sure it is worth it for a single film - faster and more efficient with hand processing. Time will tell.

antielectrons said:

Thanks guys.

I ended up pre-rinsing 5 mins (all the purple anti-halation dye washed out!)

Then processed the Tri-X 400 @ 20ºC for 10 mins.

Stop: Ilfostop

Fix: Rapid Fixer

Ilfotol washaid.

= Negs look overdeveloped (thick), very dark highlight areas... either overexposed or overdeveloped. Will try 25% less development time next and see what that does.... The constant rotation of the drum has to have an effect on development, surely?

The machine sure does use a lot of water! Not sure it is worth it for a single film - faster and more efficient with hand processing. Time will tell.

Click to expand...

Certainly John Tinsley in his Rotary Processing Manual suggests 5 mins pre-wash and then using hand agitation times.

You've lost me on using a lot of water. Are you referring to the amount needed for the water bath to maintain temp? My CPE-2 requires about 13 litres IIRC but if the developer temp is about 20 degrees C then unless the room temp is a lot colder than 20 degrees C then rotating above a water bath at 20C or rotating above just enough water to cover the heating element is unlikely to make much difference to the developer temp even over 10 mins. It may be worth trying rotation with just water in the tank starting at the correct temp and checking the difference after 10 mins. Different story of course if room temp is much lower. Then a full water bath is likely to be essential to form a heat "curtain" around the rotating tank.

Pentaxuser

I don't think you should try running a CPE-2+ completely dry. Make sure the element and temperature sensor are covered. You don't want to trip the overload because the heater did not turn off at ambient temperature.

Dense highlights usually indicate over development, but without seeing the shadows and mid-tone placement it is hard to be sure. The Jobo does keep stable temperature, and the pre-rinse does stabilise the tank and film. Unless you pre-rinse with a hand tank you may be running your developer a little cold.

I'm not convinced that the rotation in a partially full tank has much difference over 1-2 inversions per minute in a hand tank. If anything I think I under agitate by hand for normal processing.

The odd thing about using rotary tanks is that you have to allow for minimum and maximum solution volumes, and make sure you have enough active ingredient for the film area. You generally just add another unit of volume for each extra film with a hand tank.

There are enough changes in variables that you _have_ to run a test or two.

Hi,

The water comment was about how much water it takes to fill it (I read 7.5 litres somwhere, which is what I have been using).

Just found this in the ilford info leafltet for ID-11 - which supports info supplied by JOBO - that with pre-rinse use your normal hand times but without pre-rinse reduce time by 15%:

---------------------------------------------------------
Rotary tube processors have very similar
processing conditions to spiral tank processing by
hand, except they process with small amounts of
solution using continuous agitation and can be
pre-programmed. PERCEPTOL, ID-11 and
MICROPHEN can all be used to process films in
rotary processors using either stock or diluted
solutions 1+1 and 1+3 at 20oC (68oF).
Follow any guidance given by the processor
manufacturer when adjusting process times for
these types of processors. However, generally we
do not recommend using a pre-rinse as it can lead
to uneven development.
Without using a pre-rinse the given development
times will need to be reduced by around 15% to
compensate for the continuous agitation.
---------------------------------------------------------

I've had my CPE2+ for a moment now...

actually a month or two, but by the time I got all the necessary plastic bits to have it work properly, it's only been today I've started doing rotary processing.

When I measured the temperature of the developper (DD-X 1+4 for HP5+), it was 21.5°C, so I put in a time of 8 minutes instead of the 9 for 20°C.

The ease of use of the whole thing is pretty nice. Hey! No more staying in the bathroom all the time!

As to the result, it is nice, maybe a bit more contrast then with regular inversion, but that's OK for me for now, as those pictures needed it.

As to pre-wetting, most Ilford documents don't recommend it so I don't feel like doing it.

If the contrast is too high, reduce developing time by 10%.

You should aim for development by manual tank and rotary processing to have the same result.