Understanding RA4 replenishment formulas

Fatih Ayoglu · May 16, 2023

Dear all,

As I have started to print RA4 at home, currently using one shot method for each drum. Not quite sure but I think I am wasting too much chemistry. (Each 8x10 drum takes 75ml, each 12x16 drum takes 150ml chemistry). So I am re-reading the instructions for the RA4 Developer from Tetenal, specifically, SP160

So according to the manual replenisher is 9:1, so 900ml water to 100ml developer and then 160ml per m2, that will mean 16x 8x10 prints for me

The manual also provides 2 options for working solution
1) 700ml replenisher + 25ml starter + 275ml water to make 1 litre
2) 905ml water + 70ml developer + 25ml starter to make 1 litre

So am I right in thinking that, if I choose option 1, I just need to add 160ml replenisher for each 16 8x10 prints? Is it safe to use this method in drums? Obviously replenisher system works out cheaper but paper is more expensive the chemicals and I am not quite sure if replenisher option works for drums.

Many thanks,
Fatih

mshchem · May 17, 2023

Fatih Ayoglu said:
Dear all,

As I have started to print RA4 at home, currently using one shot method for each drum. Not quite sure but I think I am wasting too much chemistry. (Each 8x10 drum takes 75ml, each 12x16 drum takes 150ml chemistry). So I am re-reading the instructions for the RA4 Developer from Tetenal, specifically, SP160

So according to the manual replenisher is 9:1, so 900ml water to 100ml developer and then 160ml per m2, that will mean 16x 8x10 prints for me

The manual also provides 2 options for working solution
1) 700ml replenisher + 25ml starter + 275ml water to make 1 litre
2) 905ml water + 70ml developer + 25ml starter to make 1 litre

So am I right in thinking that, if I choose option 1, I just need to add 160ml replenisher for each 16 8x10 prints? Is it safe to use this method in drums? Obviously replenisher system works out cheaper but paper is more expensive the chemicals and I am not quite sure if replenisher option works for drums.

Many thanks,
Fatih

I looked at the instructions on Freestyle.
I believe that option 1 that you have above is to make working "tank solution" ie working solution developer.

The tank solution, prepared as you have in your example 1 can be used 1 shot, or collected and replenished with your ready to use replenisher that you have purchased 4x1 liter bottles from Tetenal.

Not clear what replenishment rate is from what I looked at.

Using one shot you should be able to get 15-16 prints from each 1 liter bottle of the ready to use (RTU) developer replenisher you have purchased.

mshchem · May 17, 2023

Ah, just looked further, replenishment rate is 160mL/ m2 of the RTU monoline developer replenisher. Add the replenisher back into your working solution developer discard any extra used working-strength developer after topping off your working bottle (tank)

mshchem · May 17, 2023

8x10 is roughly 1/20th of a square meter so 160/20 is 8mL.

So you mix up a fresh 1L os working-strength developer (your example 1)

You process 5 prints, using 90mL each time, you collect the once used developer in a beaker.

Then you add (8mL x 5) = 40mL of the RTU replenisher to your 1L bottle of working-strength developer, then top the bottle off, back to 1L with the used developer (if there is any extra used not needed to top off the 1 liter bottle this can be tossed)

Fatih Ayoglu · May 17, 2023

mshchem said:
8x10 is roughly 1/20th of a square meter so 160/20 is 8mL.

So you mix up a fresh 1L os working-strength developer (your example 1)

You process 5 prints, using 90mL each time, you collect the once used developer in a beaker.

Then you add (8mL x 5) = 40mL of the RTU replenisher to your 1L bottle of working-strength developer, then top the bottle off, back to 1L with the used developer (if there is any extra used not needed to top off the 1 liter bottle this can be tossed)

Thank you so much, exactly what I needed to understand how the method works after mixing all the chemicals.

Fatih Ayoglu · May 17, 2023

mshchem said:
I looked at the instructions on Freestyle.
I believe that option 1 that you have above is to make working "tank solution" ie working solution developer.

The tank solution, prepared as you have in your example 1 can be used 1 shot, or collected and replenished with your ready to use replenisher that you have purchased 4x1 liter bottles from Tetenal.

Not clear what replenishment rate is from what I looked at.

Using one shot you should be able to get 15-16 prints from each 1 liter bottle of the ready to use (RTU) developer replenisher you have purchased.

And you think, the replenisher method works for drum processing? Asking this only because with using drum, we aerate the chemicals quite a bit so some folks were saying for drum processing, we should go one shot method.

koraks · May 17, 2023

Your concern is valid and replenishment rates may need to be higher in drum processing. But I would propose to try it with the manufacturer's recommendations and take it from there. If you run into noticeable inconsistencies, you can always adjust your methods.

mshchem · May 17, 2023

Fatih Ayoglu said:
And you think, the replenisher method works for drum processing? Asking this only because with using drum, we aerate the chemicals quite a bit so some folks were saying for drum processing, we should go one shot method.

I use RA-4 one shot. Replenishment rates apply for roller transport machines and especially for minilabs. I have a little Durst RT machine that I've used, but mostly I use tubes or an old Kodak drum machine.

One method I have used in the past is to save the once used and mix this 50:50 with fresh.

With tubes and any machine use starter! I spent a day trying to figure out brown staining on prints, needed starter, I simply forgot to add it to the mix.

Fatih, I agree that the best way to use your "drums" my "tubes" is one shot.

Glad to hear from you, keep printing!

mshchem · May 17, 2023

I still use these machines

MattKing · May 17, 2023

If you are replenishing, you can use much larger volumes of chemicals, without there being any cost penalty.
That may help a bit with oxidation - less tumbling of chemical through the air, and more moving of paper through chemicals that are closer to being stationary.

Fatih Ayoglu · May 18, 2023

Thanks all. So if my math is correct, from 1litre of replenisher solution described on Tetenal instructions, I can get 30-35 8x10 prints. That uses 100ml developer and 25ml starter. If I use one shot, that is around 23 8x10 prints.

So to test how it will work, I will use 10ml replenisher per each 8x10 print and test this method for contact sheet printing where exposure/color does not need to be great. If it works great, if not go back to one shot method.

I'll report back in due time.

BW,
F

DREW WILEY · May 19, 2023

It's soooo much easier and more reliable to use drum chemistry one-shot, and mix only enough at a time for a daily session. I've never had good luck with Tetenal, but have reliably used Kodak RA/RT and its generic equivalents. Right now, I'm using the chemically-identical Silver Pixel kits from Freestyle. Drum brands differ one to another in their efficiency, and they need to be run level. Always use a correct temp water cycle first, to get the inside of the drum up to the right temperature before developing. I need only 1/2 US fluid ounce of Dev or Blix in an 8x10 drum, and only half a liter for a full 30X40 inch print drum; so if properly done, one-shot processing doesn't need to consume a lot of chemistry at a time.

If you do decide go the replenishment route, you want to monitor how consistent the prints are down the line. I'm skeptical they'll all come out the same. It's not like using a roller-transport processor designed for replenishment.

Understanding RA4 replenishment formulas

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