RA4 mixing question
I finally go around to mixing my first batch of RA4 chemistry today, with the plan to get in the darkroom this weekend. I bought the two kodak 20L dev and blix kits from here: http://www.ag-photographic.co.uk/process-ra4-117-c.asp. This is a great kit as it is split into small bottles with the idea of making 4 x 5L sets of working solution, however I only wanted to mix 2L of working solution.
Unfortunately the small bottles only have basic mixing instructions - 3.75L water +part A, B & C + water to 5L. None of the bottles had individual volumes on them. I think I measured them correctly, but I'd appreciate it if anyone who has used this kit can confirm my measurements.
For the developer I measured part A=250ml, part B=150ml, part C=250ml. For the BLIX I measured part A=710ml, part B=1L. Please can someone confirm these.
Assuming I got these right, my next question is about using them in trays. My darkroom temperature is cold right now, probably 15 degrees C, so room temperature is very low for developing. I'm planning on using the small heater I use to maintain water temperature for C41 development. I wanted to just submerged this in the developer, do you think this will work?
As I only have one heater, I was planning on using the stop and blix as room temperature. This shouldn't cause a problem should it?
Thanks for your help.
Originally Posted by Simonh82
As for your volumes, this should list them
For the Kodak 20 litre packs you need:-
50cc of Concentrate A
24cc of Concentrate B
50cc of Concentrate C
and 80cc of developer starter.
This is for 1 litre of working solution, for 2 litres simply double the amounts.
They must be mixed in warm water (The temp required is on the main instructions supplied) or they do not mix properly.
For replenishment:- (I assume you are using a tank like a NOVA) The dilutions are exactly the same, but miss out the starter concentrate. If you are using a rotational development such as a JOBO, then you will need to use the starter for every mix.
I always store any unused developer in 500cc dark brown glass bottles away from the light and you will find this stays fresh for a long time. I also decant one of these bottles into 5 x 100cc dark brown bottles as I find 100CC is enough for one evening s work so you empty the bottle but the others have little exposure to air and oxidisation.
If you are using a tank like a NOVA, you will find that after finishing for the evening, and replenished the developer and replaced the floating lids. Covering the tank top with 'cling-film' will also help to reduce the onslaught of oxidisation. I have used a NOVA tank with replenished developer for up to 18 months before I had to drain it to get rid of the Tar de[posits
The Kodak datasheet I am looking at essentially says for RT developer (no additive):
25mL of Ektacolor RA Developer Starter
within 1 litre for working solution, and working solution being more diluted than replenisher.
Correct answers posted above... but all reports I've read indicate that Kodak RA4 developer (I bought the same kits as you) keeps better mixed to stock solutions than as opened concentrates. The advice I got here was to make up one full 5L batch of developer and store it in an aluminised mylar bag (wine/water cask).
I don't believe you need to mix up the blix and personally I think it's probably a slightly bad idea because (as a generalisation), bleaches eat fixes when mixed. I did find with the Kodak chems that you cannot run the bleach and fix separately; there are buffering agents in the fix that are required to get the pH of the bleach correct and remove all the silver. Running them separately gives retained silver in the prints (high contrast, low saturation).
For blix replenishment, I have mixed my bleach and fix concentrates into two "half mixes" (2.5L each) with water; when I want to do 20mL of blix replenishment I just use 10mL of each half-mix. That keeps them separate in the long-term on the shelf (combined only in the working solution) but makes the replenishment process pretty easy because I don't need to do dilution at that point.
If you're using a Jobo like me, oxidation is an issue. You will probably kill a 2L working solution from oxidation before it runs its official capacity, so you're better off (IMHO) running about 250mL of working solution, which means it gets turned over completely by replenishment (15mL/sheet, though in theory 10 is acceptable) every 16 sheets instead of 130. I've used only a few mL of starter (for the 250mL) and just kept on replenishing that and never starting a new batch. It keeps really well on the shelf, unrefrigerated, as long as you exclude oxygen with butane.
Edit: just saw your trays note; disregard the above. 2L will be fine I'm sure.
Last edited by polyglot; 11-01-2012 at 10:23 PM. Click to view previous post history.
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I don't know if we are talking about the same concentrates here but if we are simple maths tells me your dilutions will be too weak. Each of the bottles in the 20 litre kits I use which are labeled A and C contain 250cc of concentrate. The bottle marked B contains 120cc.(2 x A. 2 x B and 2 x C in the 10 litre kit).
Originally Posted by Athiril
Divide each of these bottles by 5 because the contents will make a total of 5 litres and you get the figures I gave before.
The replenisher solution must be the same as the prime solution.
I did make a slight error in the wording regarding the starter solution where (Kodak Ektacolour RA Starter) I quoted the 80cc for 1 litre. This is is for 2 litres, however the quantities of starter is not critical so doubling the concentration would not make a great deal of difference
I cannot say about the bleach fix because I don't use Kodak Blix. I have a much cheaper alternative.
As for mixing the whole kit or half the kit at once is bad practise Diluted solutions have a very limited shelf life compared with concentrates.(Not my words - Kodak's)
I have found this to be very true and in the 20 or so years of using these kits I have never had a problem with life of either concentrates or dilutions. The concentrate in part A is the only one that has a tightly restricted life when opened but this can be assisted by keeping it in a closed light tight container in a cupboard.
Last edited by BMbikerider; 11-02-2012 at 09:37 AM. Click to view previous post history.
I gave up on mixing full amounts and only mix enough proportionately for a single day's work session,
immediately prior to use (allowing enough time, of course, for the chemistry to reach temperature
equilibrium in the tempering box or water jacket). And I develop one-shot in drums. This has given
more consistent results than mixing a week's worth, for example, at one time. But I'm nitpicky about
Thanks everyone for the information. It sounds like I have probably got the right dilutions, although my developer part B, definitely had more that 120ml in. I'm not using starter, so I know that my developer may be a little hot, so to speak to begin with. At the moment I'm not looking for exactly repeatable results, just having some fun making some prints.
I'm going for trays at the moment rather than drums as i'm used to them and don't think I will mind working in the dark for a couple of minutes. I almost won a Nova quad a few months back, but the seller withdrew it just before the auction ended. Saying that, I have no idea where i'd store that when not in use.
I've read on here that the working solutions last much longer than the concentrates which I find really hard to believe. I don't want to mix up 5 litres at a time, partly for the fact I have run out of space to store anything and if I have even more giant bottles lying around my girlfriend will kill me. 2 litres I can stash away a bit easier and if I end up having to chuck the remaining concentrates from the opened bottles i'll think again but it won't be the worst loss.
BMbikerider - Were do you get the 10L kits from? the 20L kits seem like good value, but I'd prefer smaller size in future.
Here are the 10L kits:
But I prefer to special order from my local camera store.
Yes, it has been posted many times on this forum that working solutions of color developers, stored in glass (and possibly high quality plastic) jars filled to the top can have a very long life as oxidation is minimized. I use glass canning jars, readily available in different sizes. I always mix the whole amount at once and stored this way I have had RA-4 and C-41 developers last more than three years with results indistinguishable from fresh, and little change in color of the chemistry.
Originally Posted by Simonh82