RA-4 chemicals: which Kodak product for rotary tank processors (Jobo)?

[tgtaylor]

If you use it aas "one shot," the 10L kit http://www.adorama.com/KKRADRRT.html will make 12.5L of working tank solution. For mixing instructions see the Kodak Pub CIS-49 Preparing Smaller Than Package Size Amounts of Kodak Procesing Chemicals on Kodak's website.

[SamReeves]

Starter is important for these developers and bleaches (especially in E-6 and C-41 if its required).
They kick off a seasoned tank solution which helps to minimize variations in color and density.
Kits like the kodak 1 gal e-6 and the c-41 1 gal dev have the starter mixed in or as part of one of the mixes.
A good thing about the starter concentrate is they last almost forever.
IIRC, In one of the kodak tech pubs i read they have the life listed as indefinitely.

Im sure you can use it without but the results can be unpredictable and repeatability can become an issue.
I accidentally forgot it once in the E-6 CD and it didn't look good to say the least.
RA4 may be a bit different in that you can compensate with a different filter pack.

It's not a big jump on the filter packs. That's always going to change a little between printing sessions. I've never used the starter with the Kodak RA-4, but then again I'm mixing the chemistry to be one shot for the developer. I've never replenished squat.

[IanMazursky]

I dont replenish developers either since i run it in a rotary tube, it mixes in to much air.
I spoke with a kodak tech years ago and he gave me some good reasons to use starter so i do
It was also needed when i used to run control strips and i was plotting everything.
Even used as a one shot, the plots went way to far out when i didn't use the starter.
Starter is inexpensive and shelf stable. If it says its needed for the particular chemistry i use just to be safe.
I know some of the color chemistry doesn't need it, maybe RA4 also falls into that category since you can compensate.

Im getting back into color here for my LVT so i have to start the plots all over again. Fun fun!
I still have starter from a few years back that is perfectly good so i will use it.
I guess at some point i can try to see if there is a big enough difference. But it doesn't seem to be worth the few pennies saved.

[tgtaylor]

Does the "RT" in Kodak Ektacolor RA Paper Developer / Replinisher RT stand for "Room Temperature?" I'm beginning to suspect it does and would explain why I'm limited to 10 to 15 second exposures at f16 @95F in a Jobo.

[IanMazursky]

RT stands for Roller Transport.
The RT set of chemicals where meant for roller transport processors.

"KODAK EKTACOLOR RA Developer Replenisher RT
This developer has built-in protection from oxidation and evaporation that makes it particularly suitable for roller-transport processors and continuous processors with low utilization."
http://www.kodak.com/global/en/busin...?pq-path=12552

Kodaks manual J-39 has a little more info on using Kodak RA4 chemistry in a jobo.

[tgtaylor]

The reason I asked was because PE and others on apug advised against using the starter if one was processing at room temperature ("RT"). As I never even thought about RA4 processing at RT, I thought the RT designation could stand for room temperature.

You learn something new every day around here!

[IanMazursky]

If PE said to use it without a starter i would take his advice.
He is the master of this alchemy!

When you run out of the RT, i would test the regular RA4 paper developer for the jobo.
I know a number of jobo users who use the regular RA4 dev and can expose at whatever they want.

I think Tentenal still makes a room temperature RA4 kit.
I bought one a few years back and didn't have much success with it.
But that could be due to the Ilfochrome printing filters in my D2 and my attempt at tray processing.
Not an ideal situation at the time.

[Larry Gebhardt]

I forgot to mention that when I use the Jobo I use 25RPM to keep the oxidation down.

Also get some of the Kodak Test strips. They will save you major headaches if you somehow contaminate the components, or mix improperly. I don't bother to plot them with a densitometer, I just run one periodically throughout the day. Visually you can get a good feel if things are going ok as far as replenishment, or if you aren't washing the drum enough and have contaminated your developer.

[al olson]

Thanks, Ian, your information may have solved my problem.

I have been using a DoMac roller transport for 10 years now. Initially, I was buying the RA-4 chemicals from an east coast supplier. However, I found the Kodak chemicals to be much cheaper so I reset the temperatures to use the Kodak.

My problem is that when I process paper 11x14 and larger, the last inch or so, depending on the color, becomes noticeably lighter. I have blamed this on the fact that after the end of paper passes by the lucite rollers that hold it in the bottom of the developer trough, it pops up out of the developer.

I have theorized that the developer has become locally exhausted at that point and misses a few seconds more agitation that the rest of the paper received.

I never had this problem with the other developer in the DoMac. The Kodak RA-4 works fine in the Jobo and I have been using the Jobo for my final prints. However, the DoMac is more convenient and I still use it for making test prints with a lot of refreshing.

I was never aware that there was an RT version of RA-4. I had never seen it stocked in the photo stores, only the non-RT version. From reading the Kodak links in your post, it seems that I should be using the RT to solve the DoMac problem. I am going to request that my photo supplier order a few gallons of RT with their next shipment.

Thanks again,