Kodak RA/RT Usage Advice (Replenishment)

Bumba · Dec 5, 2019

Hi, I've searched high and low to get as much information on this kit as possible but I've got some questions left.

I know many of you use it as a room temperature developer. I'm planning on using it in drums but I'm in the UK so the kit costs a fair bit (think it's probably cheaper in America). It's costing £120 for both the dev and blix 20l kits. I would like to use it as a replenished system if possible. I searched through the Kodak documents and got roughly a value of 14ml per 10x12 (10ml per 8x10) but this seems a bit low to me. I was thinking more along the lines of 40ml which is 1/3 of what my drum requires. Does anyone have any advice for a replenishment system?

Also are these chemicals best used at room temp or higher temp. I'd prefer to use it at room temp but it's not much issue heating them up if it increases the image quality.

Thanks for any help
Bumba

Wayne · Dec 13, 2019

Can't help on the replenishment question but you already answered the other part. There are a fair number of people using it at room temperature so I don't think you will have any troubles on that.

Bumba · Dec 14, 2019

Thanks Wayne. Do you know if its used one shot and with a pre wash?

koraks · Dec 14, 2019

If you use a replenishment system it's obviously not one shot. You can do one shot if you want; I personally replenish but I use fuji chemistry. I check pH a few times during a session and replenish to keep it within reasonable margins. This is with tray development BTW, but I'd do the same with drums.
I develop at room temperature; also tried higher temperatures but didn't note any benefits apart from shorter development times.

Bumba · Dec 16, 2019

Thanks Koraks. That helps a lot and I think I've got it planned out in my head how I'm going to do it. Could you give me an idea of how much you replenish per sheet and what PH level is desirable for both dev and blix. I was planning to replenish at 25-30ml per 10x12 sheet (320-390 ml/m2)

perkeleellinen · Dec 16, 2019

Hello Bumba - not sure if this is of any use. I use a Nova processor for RA4 with the Kodak chemicals. Each slot holds a litre and I normally replenish 100ml dev every ten 10x8 prints.

koraks · Dec 16, 2019

@Bumba, check out the datasheets for your chemistry; it will list the specific values for the stuff you use. Kodak usually offers excellent data and guidelines for this. I could dig up the values I use for the fuji stuff I use, but it will be different than Kodak's, especially the developer pH value which could easily be 0.15 more or less from "my" target pH. Generally it's somewhere around 10.25 for the developer. I think Blix is usually around 4.5.

Bikerider · Dec 16, 2019

I have used Kodak RA4 for around 30 years. The replenishment rate is 10cc of both developer and blix per every 80 sq inches (one sheet of 10x8) What I do is keep notes of each piece of paper I use including test strips and add the total area up at the end of the session. If it is over 700 sq inches I round it up and replenish with 100cc. It is designed to be used at 35C and developed for 45 seconds. I do not know of any official approved times for cooler temperatures.

Recently I have been using Tetenal RA4 and to be honest I personally find it NOT to be as good as the Kodak. I only used it because the Kodak was in short supply. It has been suggested to me that the Tetenal already contains the starter or the equivalent and that does not give the longevity which is the hallmark of Kodak. I have had to ditch the last lot because it went stale despite adequate replen. By longevity I mean replenished exactly as suggested by Kodak. I have used the Ektacolor RA4 in a deep tank for over a year and only changed it to let me get rid of the sludge build up!

Bumba · Dec 18, 2019

Thank you all for your help and its very insightful. I'm changing over from Tetenal to Kodak as the price of Tetenal is too much now (£70 for 5l). The Kodak is still expensive but I want to get the most out of it to reduce long-term cost.

Do any of you have any tips on storage. I normally leave blix as concentrate and mix up developer all together. Is developer more stable as concentrate or mixed solution? I usually use plastic bottles too and will probably stick to that unless anyone has had a bad experience with that method.

Thanks for all your help. I find colour printing is pretty fun and not too hard but looking after chemicals to be the biggest headache. If I can work it out then I'm sure I'll have more fun.

perkeleellinen · Dec 18, 2019

I mix up both dev and blix and store in one litre pop bottles with the air squeezed out. I've had success printing from chemistry like this that was two-three years old. Never had a mixed solution go bad, but had a few bottles of concentrate dev B go bad.

koraks · Dec 18, 2019

I've had plastic bottles of various kind dissolve in the developer, either as a concentrate or working solution. I generally store the concentrates of both bx and dev.

mnemosyne · Dec 18, 2019

Bumba said:
Do any of you have any tips on storage. I normally leave blix as concentrate and mix up developer all together. Is developer more stable as concentrate or mixed solution? I usually use plastic bottles too and will probably stick to that unless anyone has had a bad experience with that method.

First, please double check the correct designation of the kit you are using. I think the kit sold in the UK is RT/LU, not RT/RA. These are different kits.

I have found the RT/LU developer has excellent keeping properties when kept in 5 Liter wine bags ("bag-in-box"). The replenisher will keep for at least 12 months without degrading. Also, the actual developer tank solution is stored in similar bags between uses and will keep very, very long. I never keep partially full concentrates and always mix up the whole five liters.

I keep the RT/LU Blix replenisher in large PET bottles. Used Blix is kept in same 5 liter wine bags as developer. My current tank solution is about 4 years old (has been constantly repelenished, but with long/several months' intervals of storage/non usage in between) and doesn't show any signs of sulfurization.

Bumba · Dec 18, 2019

Thank you all once again for the help. The information is so useful.

Yeah my version is the RT/LU kit. I did consider the wine bag option but decided against it because I thought the thicker walls of a plastic bottle would protect better against oxygen but I guess it doesn't matter too much over a short period of time.

Still unsure about weather to store the blix as concentrate or mixed, only because I read a few things saying that the nature of blix is unstable and the part A and part B work against each other.

One more thing (sorry for all the questions), but to those of you that reuse chemicals, do you use a pre-wet or stop bath?

mnemosyne · Dec 19, 2019

Bumba said:
Thank you all once again for the help. The information is so useful.

Yeah my version is the RT/LU kit. I did consider the wine bag option but decided against it because I thought the thicker walls of a plastic bottle would protect better against oxygen but I guess it doesn't matter too much over a short period of time.

If you want to keep your solution for a couple of weeks, I agree that it probably doesn't make a difference. If you want to keep your solution over months or even years, which is ususally the case in a replenished system, I would strongly encourage you to re-consider.

The material of wine bags is a laminate containing a layer of EVOH. EVOH is a much better oxygene barrier than any of the materials currently used in typical plastic bottles. It was specifically developed aiming at its properties as an oxygene barrier, to protect food and beverages like wine from oxidization. In numbers, EVOH is around 10,000 times more resistant to oxygene permeation than HD-PE, which is a typical "high quality" plastic bottle material like the ones the concentrates of the Kodak kit are packed in.

The greatest benefit of the the wine bags is however that they are the only storage option that will keep the replenisher solution strictly and at all times separated from oxygene. Everytime you pour some replenisher from a plastic bottle, fresh air and oxygene will stream into the bottle. Zero air will stream into a wine bag when you draw off solution.

mnemosyne · Dec 19, 2019

Bumba said:
Still unsure about weather to store the blix as concentrate or mixed, only because I read a few things saying that the nature of blix is unstable and the part A and part B work against each other.

One more thing (sorry for all the questions), but to those of you that reuse chemicals, do you use a pre-wet or stop bath?

C41 blix has a bad rep for breaking down but it should not be confused with RA4 blix, which was different properties and is much more stable than C41 blix. As I have written above, I had no problems whatsoever with long term storage of Blix replenisher and tank solution from the RT/LU kit over several years (!) in PET containers and wine bags respectively. Store the blix at normal room temperature it does not like too cold temperatures, IIRC.

I reckon reusing the chemicals would make it difficult to include a prewet and a stop bath. The prewet will dilute your developer over time. The stop bath will change the blix pH over time. OTOH, it might be not relevant as long as you permanent "tank" solution is large enough (something in the 3-5 liter range).

Bikerider · Dec 19, 2019

Bumba said:
Thank you all for your help and its very insightful. I'm changing over from Tetenal to Kodak as the price of Tetenal is too much now (£70 for 5l). The Kodak is still expensive but I want to get the most out of it to reduce long-term cost.

Do any of you have any tips on storage. I normally leave blix as concentrate and mix up developer all together. Is developer more stable as concentrate or mixed solution? I usually use plastic bottles too and will probably stick to that unless anyone has had a bad experience with that method.

My way with Kodak RA4 mix to initially make up 2 litres, this includes the developer starter.. You will have to do a bit of maths to work out the proportions. This will go directly into the will go into the nova deep tank as a fresh solution. I also make up 2 litres of developer replenishment solution and split these into 3 x 500cc glass bottles and the remaining 500cc will be split down into 5 x 100cc bottles to be used at the end of a session. The remaining stock solution will keep for a remarkably well for a good few months, especially the unopened bottles.

Each of the glass bottles can be treated with an inert gas to exclude the oxygen in the atmosphere or as I do. I heat the full bottles in a microwave ( Hope you have an amenable wife) Not boiling of course but to around 50-60degrees C. Then the bottles are capped when they are still warm. As the bottles cool, the small gap at the top of the bottles forms into a partial vacuum so loosing the oxygen. I have kept even pore mixed C41 for several months, and as RA4 is more stable you won't have a problem.

Bumba · Dec 19, 2019

Thank you guys so much for the information. You're like a fountain of knowledge. There's a lot to take on there and I feel ready to take on the colour printing beast. P.s. no wife as of yet so I get a lot of time to put into photography plus I'm in my 20s so I don't have many responsibilities.

If you guys feel I missed anything important then please feel free to add it.

Once again thank you very much for the information.

perkeleellinen · Dec 20, 2019

Be sure to report back when you start making prints.

I wish I'd tried colour back in my 20s but I believed all that nonsense about it being too 'difficult'. Now I have responsibilities and snatch any time I can to print!

Bumba · Dec 20, 2019

Yeah I was really on the fence about getting into it and so far it's been highly unproductive but I heard photographers saying how important it was to print your stuff. I never get on well with a scanner and Photoshop too so thought I'd take the plunge now whilst I have the time to dedicate to it and learn. Plus there's not much else to do when you're in the UK and 2/3 of the year it's raining haha

Bumba · Dec 22, 2019

I'm back already haha. All this stuff has just been running through my head recently. Anyway I decided that I'm going to keep 3l of replenisher in a wine bag and the other two in glass bottles for longer term storage. I decided on the ones with the flip tops (like bottles of Grolsch). I'm using the 3l bags and not the 5l ones because I process upstairs and have to keep chemicals downstairs so it would be a pain taking 10l or replenisher up and down. Would be a good work out though.

Anyway I was considering the blix and I've read that it needs oxygen to work. Is it a good idea to store it in glass with no air or should it be stored with a little air inside or in PET bottles where air can permeate a little of would the oxygen lead it to go bad. I'm looking at storage of around 9 months.

Also is it necessary to use distilled water or water with the oxygen boiled out for mixing for this length of storage?

Thanks guys

koraks · Dec 23, 2019

The less oxygen the better for long term storage.

Bumba · Dec 24, 2019

Okay thanks Koraks. I think I'm ready to tackle RA4 again. I'll report back when I'm up and running.

Bumba · Dec 26, 2019

I'm back already because I had an idea haha. Would this be a good idea?

Let's say that I want to store a litre of blix and have 150ml part A and 200ml part B. As it would be difficult to find bottles to store such small quantities without air inside could I store each part separately in 500ml bottles topped with water. Then you have 2 full bottles of separate part A and part B that are diluted. When you need the blix then you just mix the two components directly together.

Wouldn't this solve the problem of oxidation and also be stable or is this a bad idea and I've lost my mind?

koraks · Dec 26, 2019

Diluting the concentrates will reduce the lifetime of particularly the fixer part, but it will likely still last a few weeks to a few months in a full bottle. The bleach part will likely store well for months or even years. If you go this route, make sure you calculate the dilution properly since you'll have water in both bottles and that obviously needs to be added up. The volumes you have listed in your example don't add up to a logical dilution, but there's some margin for error when it comes to Blix (of course try to stick to the manufacturer's specification as much as possible).

Bumba · Dec 27, 2019

Oh man I wish I was better at Chemistry haha. I think I'll just store them as working solutions and save the headache of looking too much into it. I'm probably thinking too much about it

Kodak RA/RT Usage Advice (Replenishment)

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