Questions for printing RA4 at room temperature.

I am about to try printing a 30x40 color photograph using a drum processor that has no temperature control capability, and thus, I will be processing the print at room temperature using RA4 chemicals. I also have a smaller drum for processing smaller prints that I hope to use for my test prints. I will be making a 10L mix of Kodak Ektacolor RA-RT developer replenisher. I will be using the replenisher solution and NOT the starter solution to develop my prints. I will start with a water prewet step and add a stop bath step just after the developer step and before the bleach fix. I have a number of questions:

1. Room temperature for my darkroom is around 60F. Is this a problem? Any recommended develop times? I was thinking about using two data points (68F, 2’30”) and (95F, 0’45”) to derive a straight line equation for predicting the processing times needed for a given room temperature. Is this approach plausible?
   
2. I will be mixing the RA-RT developer and RA bleach fix with Kodak RA additives for each chemistry to reduce oxidation. Will this be a problem for process at room temperature?
   
3. How sensitive is RA4 processing to variations in agitation? I have not figured out how to secure and 8x10 test print inside the 30x40 drum. My plain is to us a smaller drum for processing the 8x10 test prints and assume the difference in agitation between the two drums will NOT cause any visible differences in print density. Is this a reasonable assumption?
   
4. Of course, if RA-RT chemistry is agitation sensitive, then does anyone have any ideas of how to secure an 8x10 test print inside my 30x40 drum so that I can more closely mimic the actual agitation that the final 30x40 print will receive?
   
5. Eventually I hope to use Kodak test strips and a JOBO CPP2 to more accurately determine the development time needed for a given “room temperature”. The development time needed for a given temperature that produces an optimal test strip will be the development. I would repeat this process simulating a number of different room temperatures on my JOBO CPP2 processor. I would then plot the data and use curve fitting software to derive an equation to more accurately predict developer times for any given room temperature of the chemicals. Is this a realistic approach?

Thanks for any comments offered,

-Stephen

Why not heat the chemistry in a temp bath and run it at the 95-100F temps? Dev and blix times are only about 45 seconds at those temps, so the drift-down would be minimal.

I did hand-printed and processed RA-4 this way, up to 11x14 size before getting a processor (Fujimoto CP-31). Keeping the temps in a tempering bath worked fine and the temps and times were quite stable.

it would be a shame to waste 30x40 Endura (presumably) paper on experimenting at room temps, when the actual temps should be achievable.

As an aside, what are the "Kodak RA additives for each chemistry to reduce oxidation" ? I think I could use something like that. I mix up 10L of RA-RT chems for use in the Fujimoto, but the tanks I have are not sealed, though they do have floating lids. (Doran 10 gallon tanks) I am not sure how long the developer will be good for in that storage method. I thought about floating an argon/CO2 mix on top (in the storage tanks) but haven't gotten to that yet. So far I have been using the chemistry fast enough that it hasn't been an issue. But, I turned down the replenishment amount (it was set wastefully high, I think) so it should last longer now.

Thanks
-Ed

Ed, I have a CP-51 and adding the additives to reduce oxidation works very well. A few things to consider:

I remove the roller racks from both baths every evening and rinse them out. I then cover both baths with floating lids to reduce oxidation. You can purchase the optional floating lids from http://www.omegasatter.com/.

When I leave for a trip, I empty both baths into their own 2+ gallon containers with floating lids. I then flush and fill the baths with water so that the replenishing lines do not dry up. It is important to leave the cover of the processor open to vent moisture and minimize any damage to electronics. I have left my processor in this state for up to 4 months with no notable degradation in chemistry. Please note, I test my chemistry daily with Kodak test strips, a densitometer, and graph the results to check for compliance when I am running the processor. So when I say no degradation, I mean exactly that.

I am considering your suggestions about running the chemistry at 35C.

I process Fuji CA paper in trays at room temperature (20C) using Kodak chemicals (without starter) with absolutely no problems that I can detect. I develop for 2 minutes and blix for two minutes with a 30 second stop bath in between. I believe the processes go more or less to completion and therefore are not very sensitive to modest departures from these times and temperatures.

Warren Nagourney

hi Steve -
Thanks for the info. I have a CP-51 also but need to overhaul/clean it so haven't gotten it up and running yet.

I do the same with my CP-31. I drain the chems to their own bottles after a printing session, then do a 2 full fill-run-drain cycles with water in all the baths, and rinse all the racks. Also I run the replenisher unit with water to flush those lines too. It takes a while to do all that but it seems like the best idea.

Good to know that with the additives and in containers with floating lids the chems are good for at least 4 months! Impressive. I should really get into the densitometry and test strips stuff someday soon too. That's just a level I haven't gotten to quite yet.

What additives are specifically used? I've bought chemistry from pakor.com and elsewhere and haven't noticed those for sale. I probably just overlooked them. Presumably something from Kodak designed for the purpose? Is it one additive for both Dev and blix?

Since you have a CP-51 you could use that as your chemistry tempering unit. Just fill up the dev and blix, get them to 34-35c or wherever you run them normally, then drain off what you need for the drum processing from the drain lines on the CP-51. Instant tempered chemistry. ;-) The 6L capacity would be much more than needed for a 30x40 print, which would probably only need about 1L of chemistry [or less], presuming that would cover the surface in the drum you are using.

I have some 30x40 paper but haven't thought of how to use it yet, so I am interested in how it goes for you.

-Ed

Thanks Warren for your input. It gives me the confidence I need. This is my first 30x40 print I have sold for $950, and I have never tested this approach. So its got to work. I sell tons of 16x40s and 20x50s which I can process using my Fujimoto CP-51. Of all the sizes I offer, the only one I cannot process using my CP-51 is the 30x40 size, and I really do not want to have to buy a 32" processor just to handle a size I very rarely sell.

Ed, I use Kodak Ektacolor RA-RT developer and Trebla's (cpac imaging) Trecon RA Bleach-Fix. Trebla's bleach-fix is notable less expensive than Kodaks so I save myself some money. I have had no problems mixing the chemistries.

The additive I use for the developer is Kodak Ektacolor Developer Additive KP126497. It can only be added to the replenisher solution and not the starter solution. For the bleach-fix, I use Trebbla's Trecon Topping Solution. This additive can be added to both the replenisher and the bath in part because there is no difference between the two solutions.

Steve - thanks for the info on the additives. I will seek those out.

Good to know about the cheaper Trebla Blix. The Kodak RA4 blix is not too bad price-wise. Certainly not as bad as the C41 bleach... (now that is expensive... plus the hazmat shipping.. ouch.) But good to know Trebla works fine and is cheaper. I use RA-RT for my stuff too.

how tough is it to run 20" paper through the CP-51? I have read that getting it aligned and started straight can be a real pain.

thanks
-Ed

When I run a 20x50 print through, it is coming out of the wash/dry unit at the same time it is still going in. You have to sit in the dark because you cannot stuff it all in the paper compartment and close the processor lid. It is quiet impressive, and it took me a while to figure out how to make 16x40s and 20x50s. Now its no big deal.

I have made my own paper feed alignment board that mounts to the side of the cabinet that the CP-51 sits on. It is highly adjustable and takes only about 10 minutes for me to align my paper feed, the developer unit, and the wash/dry unit. I have written a document that outlines the procedure I use if your are interested.

You will also have to make some modifications to the 2nd roller rack in both the developer unit and the wash/dry unit to prevent the 20x50 paper from jamming. This is because of the way I cut my paper from a 40" roll that results in the paper's curl occurring lengthwise. The way I cut 16x40 from a 40" roll, the paper curl is widthwise and will not jam in the roller racks. I also roll the 20x50 paper around a 3" tube with the emulsion facing out to diminish the lengthwise curl, and then I store it inside a light-tight 4" tube.

hi Steve -

I'd definitely be interested in hearing more about that, and the document detailing the paper alignment jig. That sounds like a great solution. It sounds like the curl can result in jams, correct? (without modifying the racks, that is). Thanks for offering up this info and furthering the state of the art with the CP-51.

re-rolling the paper sounds like a good idea. I had thought of that but hadn't tried it, as I haven't had to use roll paper yet.

-Ed
(ed @ edsawyer . com, btw, if you have documents you want to send)