Maintaining Temperature for RA-4

Snapshot · Feb 6, 2007

Hi All,

I have recently developed some prints using RA-4 chemistry that consists of Kodak products. I'm using a tray system for paper development and I'm finding the temperature of the chemistry temperature drops pretty quick. I'm in Canada and my basement darkroom is about 62F and a cold cellar that is about 55F thanks to that cold weather. Great for keeping paper cool but not great for keeping liquids at 83F to 86F. A space heater that I'm using can get the temperature to almost 70F but it's still not enough to keep the liquids warm.

As you can imagine the cooling of the chemicals results in inconsistent results. Does anyone have any tips or tricks that I can use to keep the temperature even or at least above 83F?

Nick Zentena · Feb 6, 2007

Drums are great for this.

Other then that maybe a heating mat? The kind used for seed starting. Place the trays on the mat.

Photo Engineer · Feb 6, 2007

I use RA-RT developer replenisher with no starter and 2' at 68 degrees F. It works just fine as long as you keep the temperature constant, but this low temp is easier to maintain.

This is an excellent way to do tray processing of color paper.

PE

Snapshot · Feb 7, 2007

Photo Engineer said:
I use RA-RT developer replenisher with no starter and 2' at 68 degrees F. It works just fine as long as you keep the temperature constant, but this low temp is easier to maintain.

This is an excellent way to do tray processing of color paper.

PE

I can maintain this temperature fine. Does the RA-RT replenisher have any peculiarities I should be aware of? For example, is it a one shot mix or can I get the same number of prints for equal volumes of standard Kodak developer? Thanks in advance for your reponse.

Snapshot · Feb 7, 2007

Nick Zentena said:
Drums are great for this.

Other then that maybe a heating mat? The kind used for seed starting. Place the trays on the mat.

I have some drums and a motorized roller. Is there any information on how to use them in this context? Does temperature matter in this regard? I would presume that would be the case.

I can try the heating mat idea as it seems like a good idea.

Nick Zentena · Feb 7, 2007

Do a pre-wash with water at the target temp. That's about it.

You'll need a water bath to keep the chemical at the right temp but that's not too hard to manage.

The drums should easily keep the paper and chemicals at the right temp during the process. The water bath will deal with the chemicals.

Photo Engineer · Feb 7, 2007

The RA-RT developer replenisher can be used in a tray for an entire evening session. I forget how many 8x10 prints / liter but it is in the EK instructions.

If you use a pre-wet and/or a drum processor it is one shot.

PE

PHOTOTONE · Feb 7, 2007

Photo Engineer said:
The RA-RT developer replenisher can be used in a tray for an entire evening session. I forget how many 8x10 prints / liter but it is in the EK instructions.

If you use a pre-wet and/or a drum processor it is one shot.

PE

if I recall correctly, the RA-RT developer replenisher comes as a concentrate that you dilute with water to make "working solution" replenisher? This is what you are using in a tray, the dilute 'working solution? And, at room temperature, you are getting repeatable results at 2 minutes developing time? What is your time (at room temperature) for the Blix? do you use a water or acetic acid stop bath between?

Photo Engineer · Feb 7, 2007

At 68 degrees, I use 2', 30", 2.5', and then wash at 75 deg for about 5 - 10'.

I don't need to use a stop, although you can if you wish. I do.

It is 2% acetic acid. Once you go light, you can see the blix action take place. When dark areas clear up, that means the blix is about finished.

The developer replenisher comes in 10 liter size and I split it and make 5 liters at a time. I mix as directed and use no starter. It works just fine but the starting color balance is about 10Y different than at 100 F. I have only tested this with Endura paper.

More detailed discussion and some samples are posted on PN.

PE

Snapshot · Feb 7, 2007

Photo Engineer said:
It works just fine but the starting color balance is about 10Y different than at 100 F. I have only tested this with Endura paper.
PE

Is this an increase or decrease for the 10Y. BTW, thank you for your advice. I purchased some replenisher today and hope to get some pictures developed next week.

I'm going to also try the drum and see which results are better.

Photo Engineer · Feb 7, 2007

Well, I would suggest adding about 10Y to your filter pack, but that is just a guesstimate OTOMH.

PE

Snapshot · Feb 7, 2007

Photo Engineer said:
Well, I would suggest adding about 10Y to your filter pack, but that is just a guesstimate OTOMH.

PE

Will do! Thanks for the guidance.

Maintaining Temperature for RA-4

Privacy & Transparency

Privacy & Transparency