RA-4 Chemical Recommendations

[shallabal316]

Are you asking about this because you are reusing or doing partial reuse? Because I don't think that will matter for the purpose of your question. And of course some people do partial reuse in drums with results that are satisfactory to themselves, which is all that matters.

You may not even need the rinse after development unless you experience problems without it.

I'm doing partial reuse. I either do 1-2 liters of working dev, pour out the 300ml for the tank, and exchange 100ml per 16x20. I have not seen a noticeable color shift, but I am also possibly lacking the appropriate lighting quality in my house to notice. Doesn't mean it isn't there.

I definitely did have issues that seemed to be corrected by stop+rinse between dev and blix. Major streaking across the image. Went to Dev>Stop>Rinse>Blix>6 Drum Washes>Dry Drum, and I have not had any blemishes since. Skipping the drum drying gave me a blemished print. Pain to dry between each print, but has become worth it to save the paper.

I use an ample pre-wet, which among other things helps bring the inside of the drum to the correct temperature, then do a brief ample rinse after the stop bath, taking care that the bottom of the drum get rinsed too. It't just a bit of insurance because there have been a few instances, especially using large drums, when a bit of previous developer somewhow still clinging to the bottom, or perhaps around the entry rim, caused a blemish. The final rinsing after the Blix step I'd classify as washing instead. And I do five or six changes of water for that, AFTER the final blix; so yes, considerably more thorough washing than in commercial roller-transport processors. Why? Just a hunch that the long term result will be better, more permanent. It certainly doesn't hurt. Those extra rinses aren't for sake of cleaning out the drum, but in relation to image permanence itself. After the print is removed, I always rinse it out by itself a little more, and even gently hose of the prints itself briefly before placing it on the squeegee board.

And Wayne is referring to re-use of chemicals in a drum, presumably with a bit of replenishment, and correctly states it in the context of being satisfactory to certain people. To me that sounds like, "good enough for government work" - not my own cup of tea, or should I say, day old cup of tea. And he correctly points out that a rinse after development is not standard practice. Well, a stop bath is, and I happen to add a minor water rinse after that, just for sake of a little extra insurance, that's all.

I'm on board with doing a process that gets optimum results. I just want to obviously do that as cost-efficiently as is reasonable. I guess I am having a hard time understanding what prevents optimum results from being achieved in a drum with replenishment. I'm only familiar with using rotary, so I should probably read up on roller-processing more to better understand the difference.

[Drew Wiley]

There is a bit of difference between predictable results and optimal results. For example, I never mix any more Dev or Blix than needed for a single day's session. Or, in the case of really big prints, I'll mix it fresh for every single print plus its own test strips. That gives me the cleanest hues. But with replenishment, you're likely to have some variance in both optimal and fully predictable results. Whether that variance is large enough to bother you all depends. I'll admit I'm quite nitpicky about my own prints and have much higher expectations than commercial-quality prints.

[Wayne]

My brain was equating the rinse after developer with stop after developer. So what I meant to say is you don't need the stop after developer, unless you are experiencing problems or doing larger prints, which you are. So in your case you do need the stop. But yeah, you don't need the rinse.

[shallabal316]

There is a bit of difference between predictable results and optimal results. For example, I never mix any more Dev or Blix than needed for a single day's session. Or, in the case of really big prints, I'll mix it fresh for every single print plus its own test strips. That gives me the cleanest hues. But with replenishment, you're likely to have some variance in both optimal and fully predictable results. Whether that variance is large enough to bother you all depends. I'll admit I'm quite nitpicky about my own prints and have much higher expectations than commercial-quality prints.

I've tried the "mix per session" method, but the kits I have used require way too much precision when mixing small batch (.25ml precision). I don't trust any of my measuring devices to that level. Something I'm hoping I can solve with some different chemical options.

My brain was equating the rinse after developer with stop after developer. So what I meant to say is you don't need the stop after developer, unless you are experiencing problems or doing larger prints, which you are. So in your case you do need the stop. But yeah, you don't need the rinse.

Gotcha. It was explained to me that the stop carryover can affect the pH and lifespan of the blix, so I added that in to the process without any further research. It's working well for now, but I should do some more reading into the pH thing to see if it affects the blix enough for me to notice or care.

Thanks for the insights everyone. It's great to get such a wide range of perspective on the forum.

[Drew Wiley]

Just get a few high quality measuring graduates, a minor investment.

[Wayne]

I've tried the "mix per session" method, but the kits I have used require way too much precision when mixing small batch (.25ml precision). I don't trust any of my measuring devices to that level. Something I'm hoping I can solve with some different chemical options.



Gotcha. It was explained to me that the stop carryover can affect the pH and lifespan of the blix, so I added that in to the process without any further research. It's working well for now, but I should do some more reading into the pH thing to see if it affects the blix enough for me to notice or care.

Thanks for the insights everyone. It's great to get such a wide range of perspective on the forum.

I'm no chemist nor will anyone mistake me for one, but I'm sure Photo Engineer weighed in on this at APUG at some point, and he was one. In a quick search I found only

The stop for B&W and RA4 can be the same as long as the blix pH is 5.5 - 6.7 and the wash is sufficient to remove all chemistry. This is for proper dye hue and stability.

PE

No mention of rinse, just wash, but it was a quick search. An alternative to always rinsing might be to just check the blix pH now and then. I think it should be 6.3-6.5 but don't quote me. You might also check it after using your rinse method through a batch to see how they differ.


EDIT: Idiot me, didn't even read what I posted. PE gives the blix pH range above, duhhhhhh. I read the 6.3-6.5 elsewhere but I'll take PE's word anyday.

I would think it would take a lot of prints before stop bath lowered the blix below that range, but obviously less with larger prints.

[rob4x5]

These Ra/Rt and Arista kits ARE starter. That's all you need. What you don't need is the replenisher or stabilizer, unless you have an automated roller-transport processor.

This is somewhat reversed. I don't use the Arista, but the Kodak RA/RT kit IS replenisher. Neither are "starter". You normally add starter to RA/RT (replenisher) and other replenishers to make developer working solution, but many have found it is not necessary and use RA/RT replenisher straight,

[rob4x5]

About all I can tell you can be found here:

www.photrio.com/forum/threads/bleach-fix-capasity.14655/