First time doing RA4! Need some advice!

[Ryan282]

Hi,

I'm in the process of setting up a colour darkroom in the spare room of my apartment.
I will be processing the paper in my newly acquired JOBO CPA2 unit.
As I've never developed colour paper before, I'm unsure exactly which chemicals I'll be needing. Especially since I'm located in Sydney, Australia, and it seems there is no way to have RA4 chemical shipped internationally?

Despite this, I have found these 'ektacolor' RT chemicals by kodak.
https://www.photoresource.com.au/KODAK_EKTACOLOR_RA4_BLEACH_FIX_REPLENISHER_RT_25_p/6600985.htm

https://www.photoresource.com.au/KODAK_EKTACOLOR_RA4_DEVELOPER_REPLENISHER_RT_4_X_2_p/6600340.htm

Or, CPAC, who I hadn't heard of but were listed on the same site:

https://www.photoresource.com.au/CPAC_RA4_RT_DEVELOPER_REPLENISHER_6_X_10L_p/c10p1-1115.htm

https://www.photoresource.com.au/CPAC_RA4_BLEACH_FIX_REPLENISHER_4_X_10L_p/c10p2-1265.htm

I've also noticed that ALL these chemicals are labelled as 'RT' which I think means 'roller transport' which concerns me.


My questions:

1. Will chemicals labelled as 'RT' be able to develop colour paper the CPA2 processor? (I think I'll be using Fuji crystal archive). Will it yield good results?

2. Is there a way to have RA4 chemicals shipped internationally?

3. Will the above listed chemicals set me up to begin the RA4 process, or do I need any other chemicals? (e.g. Starter or stabiliser?)

Looking forward to seeing if anyone knows the answers to these questions, Thanks for your time!

 

[halfaman]

Here you have some information about Ektacolor RA-4 chemicals. (Yes, RT is very suiable)

http://imaging.kodakalaris.com/retailers-and-photofinishers/chemistry-agx/ektacolor-chemicals-ra4

Take a look to tech pub j-38. You need the Ektachrome starter with RT developer yo prepare working solution (not needed to replenish!!), it is also available in the site.

https://www.photoresource.com.au/KODAK_EKTACOLOR_RA4_DEVELOPER_STARTER_4_X_1_2L_p/6601090.htm

You need also an acetic acid stop bath to use between developer and blix (page 5 of j-39 document). Dilution is similar to B/W.

One important recomendation is to replenish the developer during the printing session to maintain consistency. I use 250 ml probes and I replenish 10 ml when developer solution reaches 240 ml mark. Between consecutive days I replenish 50 ml of each solution.

 

[Ryan282]

Here you have some information about Ektacolor RA-4 chemicals. (Yes, RT is very suiable)

http://imaging.kodakalaris.com/retailers-and-photofinishers/chemistry-agx/ektacolor-chemicals-ra4

Take a look to tech pub j-38. You need the Ektachrome starter with RT developer yo prepare working solution (not needed to replenish!!), it is also available in the site.

https://www.photoresource.com.au/KODAK_EKTACOLOR_RA4_DEVELOPER_STARTER_4_X_1_2L_p/6601090.htm

You need also an acetic acid stop bath to use between developer and blix (page 5 of j-39 document). Dilution is similar to B/W.

One important recomendation is to replenish the developer during the printing session to maintain consistency. I use 250 ml probes and I replenish 10 ml when developer solution reaches 240 ml mark. Between consecutive days I replenish 50 ml of each solution.

I truly appreciate your reply! Would you have any suggestions on a stop bath? I've heard you can use the same stop bath that is branded for black and white paper processing.

I've also heard that you don't necessarily need to use a stop bath? as shown in this video:


I'm not sure what you mean by 'probes,' but via your method of continuous replenishing, does this mean you never have to create a new working solution but just continuously replenish and reuse? I was under the impression that with each print you run through the JOBO, you also had to make a new working solution of developer and blix, i.e. 'one shot' use?

Sorry for my ignorance on the topic, I understand I have a lot to learn! It's all so interesting, and I guess you have to learn somehow!

If anyone else (who hasn't commented) reads this reply, please do let me know your thoughts also. Thanks

 

[Ben 4]

Hi Ryan,

I ended up using household vinegar (5% I believe) diluted 1:1 with water for a stop bath when I experimented with RA-4 a number of years ago. I initially tried a plain water stop but got occasional streaking on the prints. I read (probably in a thread here) that an acid stop would eliminate that and it did. Best of luck!

---Ben

 

[halfaman]

RA-4 is not one-shot use, you reuse the solutions all the time. That is why a stop bath and a replenishment rate are needed. The first will preserve blix bath longer and prevent streaking in prints, the second keep the activity of solutions consistent.

As stop bath you can use standard B/W acetic acid products in the same dilution. I don't know if citric acid is also suitable.

 

[DREW WILEY]

You're on the right track. I highly recommend Kodak RA/RT along with ordinary stop bath. Starter kits are all you need. However, I strongly recommend using it ONE- SHOT. This kind of chemistry is economical, and not having to fuss with replenishment saves you a big headache. Drums work best one-shot anyway. I also recommend mixing chem fresh - just enough for each printing session. You can look up charts from both Kodak and generic suppliers giving you small batch amounts. The less variables you have to contend with, the quicker you'll establish color balance and attain predictable results. Remember to use a pre-rinse (plain water at correct temp); I also like a brief water rinse between the stop both
and BLIX steps - this seems to greatly reduce streaking issues if you use enough water volume. You probably won't need a
lot of chem per se volume. Drums can be quite efficient if they are level. Be careful to allow your chem to reach correct temp
before use. I like 2 min steps at 83F.

 

[Mick Fagan]

What Drew said is pretty good advice, except use around 28ºC stay metric and you will be alright.

With regard to stop bath, I would suggest you use a bought one. Either Ilford, or Kodak or any photographic stop bath, not vinegar. There are numerous threads here about stop baths, people with great technical photographic knowledge always suggest using a correct stop bath.

Using a stop bath, will save your Blix from going off big time.

The Kodak print filters shown in that clip are really good and worth having.

Don't skimp on chemistry, possibly adding 5% extra chemistry by volume over the minimum written on the outside of the Jobo tanks will ensure you get very consistent development each and every time. I did RA4 printing with a Jobo up until the early 90's, from there I have had a roller transport paper developer.

For test prints, you can swirl the paper around a tray with warm water for about a minute, then attack it with a hair dryer; this will get you a finished test print far quicker than waiting for it to dry naturally. As long as the paper doesn't curl too badly, the heat is alright.

If at the end of summer and if there is a drought on, beware of pre-soaking paper with straight warm water. The water authorities use a flocculant which may or may not add colour streaks to your prints. I've had that happen a few times over the decades. For what it is worth, you don't need a pre-soak; I have yet to see any commercial machine roller transport machine with one and I saw a few and worked a few last century.

I would also use my right hand to help with the lifting of the tank on the Jobo, saves a lot of stress on what is probably an ageing machine. I do.

Mick.