Shelf-life of RA-4 Minilab Concentrates?

[edz]

Commercial mini-lab RA-4 chemistry sets seem to cost a fraction of the ambient temperature monochemicals.. some of the RA-4 minilab sets even appear to be more environmentally sound and safer, to provide better capacity etc. Cheaper. Better. All sounds great.. except that the stuff comes in concentrates for for at least 10 liters.. if not 2x10l or even 4x10l.. 10 liters is a lot... 20 liters is twice a lot..

The questions then are:
- How long can one (dividing into smaller bottles) store the concentrates?
- How long can one store the virgin bottles of concentrates?

 

[Thilo Schmid]

I sometimes buy minilab chemicals and share them with other amateuer photographers (as part of a buying group). The shelf life of virgin cans is at least two years if stored properly. I would expect that a full bottle of devided concentrate lasts as long, but I use them up before. The major advantage of minilab chemistry is that you can keep it in the tank of a roller transport machine until it gets too dirty. It will degenerate as fast as single-use chemicals, but can be refreshed by adding a small quantity of replenisher prior to the next use. However, you may also use this minilab chemistry one time without replenisher (e.g. in a rotary tube) and it is still more economic than amateuer/prof. chemistry

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (edz @ May 13 2003, 01:51 AM)</td></tr><tr><td id='QUOTE'>Commercial mini-lab RA-4 chemistry sets seem to cost a fraction of the ambient temperature monochemicals.. some of the RA-4 minilab sets even appear to be more environmentally sound and safer, to provide better capacity etc. Cheaper. Better. All sounds great.. </td></tr></table><span class='postcolor'>
Uh .. I would suggest that there are more problems here...

What specific chemicals are you referring to when you speak of "ambient temperature monochemicals"?

The RA-4 chemicals found in the "small" kits (I use JOBO/ Tetenal) are made to high standards of uniformity; one does not have the luxury - or burden - of modifying chemical composition from the resuts of "control strips". I'm not really familar with the operation of "mini-labs", but I would be willing to bet that the process is less tolerant of random variables.

Then again, what does the process look like? With Tetenal it is simply: Color Developer, One minute; Shortstop, 15 seconds; Bleach-fix, 45 seconds, and wash and dry.

Hmm... "better" ... I'm not so sure of that ... I know I have done color work with the JOBO that has "blown the doors off" some of the work of a well-respected nearby commercal color lab. I have the luxury of being able to make a *bunch* of prints to "get it right", without my local "boss" going into orbit over the expense ... but that added effort clouds the comparison of the two systems.

 

[Thilo Schmid]

Ed,
RA-4 is a good-natured process. The tolerances for CD and BX are relatively high above the required minimum values. C-41 is much more critical in this case. It is the same principle as B&W paper vs. film processing

You won't need control stripes in an amateuer/prof. lab environment. You will see if something is wrong with your process and it will not be a huge loss if you have to reprint a picture. This is different in a minilab process chain where several prints go wrong until you notice an error. And if your print looks good, you don't care whether your process is within the standards. It's still photography - not rocket science ;-)

BTW: you don't use control stripes to check whether your Tetenal or Jobo chemistry has finished, do you?

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 13 2003, 10:44 AM)</td></tr><tr><td id='QUOTE'>BTW: you don't use control stripes to check whether your Tetenal or Jobo chemistry has finished, do you?</td></tr></table><span class='postcolor'>
I will run "test strips" (a.k.a. "control strips") EVERY time I start a color printing session. The ColorStar is "re-zeroed" according to the analysis of the test exposure. Shifts due to chemical changes (i.e. oxidation) are compensated by adjusting the color filtration.

The RA-4 chemicals I am familiar with have one distiguishing characteristic when they are oxidized out: the color developer will darken from a "light straw" to brown.
When I am in doubt, the test strip will be acid test: color balance will so far "out" as to be unobtainable, and Dmax will be lousy when the chemicals are beyond use.

 

[edz]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>The ColorStar is "re-zeroed" according to the analysis of the test exposure.&nbsp;
</td></tr></table><span class='postcolor'>
I don't quite understand.. I "zero" my ColorStar to the paper and as long as the batch is the same I don't see the need to change. To chase the chemistry seems futile...


</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>Shifts due to chemical changes (i.e. oxidation) are compensated by adjusting the color filtration.
</td></tr></table><span class='postcolor'>
Is not that want to compensate for the chemistry better seen as the need to modify the replentish regime to keep to a more standard level? The QC paradigm of control strips seems in our context to be just as well filled using our calibration negatives and the settings for the paper using "good" chemistry.. Or am I missing something?

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>The RA-4 chemicals I am familiar with have one distiguishing characteristic when they are oxidized out: the color developer will darken from a "light straw" to brown.
</td></tr></table><span class='postcolor'>
That's where these Mini-lab sets come in as they are designed to replentishable and have demand rates that seem perfect for slot processors--- for example 100ml/m^2 for Tetenal's Ecoline BX-MR.

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (edz @ May 13 2003, 01:13 PM)</td></tr><tr><td id='QUOTE'></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>The ColorStar is "re-zeroed" according to the analysis of the test exposure.&nbsp;
</td></tr></table><span class='postcolor'>
I don't quite understand.. I "zero" my ColorStar to the paper and as long as the batch is the same I don't see the need to change. To chase the chemistry seems futile...
</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>Shifts due to chemical changes (i.e. oxidation) are compensated by adjusting the color filtration.
</td></tr></table><span class='postcolor'>

Is not that want to compensate for the chemistry better seen as the need to modify the replentish regime to keep to a more standard level? The QC paradigm of control strips seems in our context to be just as well filled using our calibration negatives and the settings for the paper using "good" chemistry.. Or am I missing something?
</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 13 2003, 12:40 PM)</td></tr><tr><td id='QUOTE'>The RA-4 chemicals I am familiar with have one distiguishing characteristic when they are oxidized out: the color developer will darken from a "light straw" to brown.
</td></tr></table><span class='postcolor'>
That's where these Mini-lab sets come in as they are designed to replentishable and have demand rates that seem perfect for slot processors--- for example 100ml/m^2 for Tetenal's Ecoline BX-MR.</td></tr></table><span class='postcolor'>
One of the first questions I have is about the duty cycle in question here. I do not *reguarly* process RA-4 paper, and when I do, it is a "small volume" run. I don't think I've ever produced more than the equivalent of thirty 8" x 10" prints in a single day.
The second consideration *I* have is that my primary concern is quality, rather than economics. I am a "closet" - and recovering, perfectionist - after working in a Metrology Lab for many moons, one learns to control and modify a nearly overwhelming desire for perfection - something given to (the) God(s), but not mortal man. Modifying doesn't mean abandoment though ...

This discussion motivated me to visit Tetenal's web site. Glory!! Anyone who wonders if film/ chemical is "dead" should do the same -- they are putting a *bunch* of research into new chemicals, new materials, new processes. Interesting.

You spoke of "Tetenal's Ecoline BX-MR" chemistry. I couldn't find that anywhere, although that could easily be my fault. Their extensive caqtalog, in .pdf format, was not an easy one to navigate.

Interesting chemicals here that I am NOT familar with. I note the trend to powder (pearl) forms of RA-4 chemistry (must have a very long shelf life) as well as a "rapid" form requiring 28 (!!) seconds of normal developing time.

Which all leads to: Where are your sources for the contemporay Tetenal chemicals?
- and where are you located? It may be that some items, like "Protectan Spray" are not being imported into the USA.

You questioned whether "chasing" the chemistry (by re-zeroing the ColorStar) was worthwhile. I mix chemicals in volumes that I intend to use in a short period of time, usualy not more than a liter at a time. Modification of chemical compostion by analysis and the addition of required chemical agents is not possible with the "Kit" chemistry I use - or at least not mentioned anywhere in their data sheets. This is where the effects of "volume" come in - if I had prepared a large volume of chemistry to use over an extended period of time, the analysis - regeneration route would be the only way to go.
Hmm ... "as long as the batch is the same.." I'll agree with that, but, mixing fresh each time MEANS a "new" batch, and although the "batch" to "batch" uniformity is very good ... there are inveitablly *slight* differences in color balance which - uh - irritate a perfectionist. "The same" also would neglect the effects of time in storage - even with measures to lengthen shelf life, this stuff DOES deteriorate- and, as near as I can tell, at a more or less "random" rate.

Intersting that you speak of "demand rates". What specific process do you use, and what equipment?

Anyway ... I'll "re-ask" ... Where can I get this new Tetenal chemistry?

P.S. How do I "split" quotes like that?

E.S.

 

[Thilo Schmid]

Ed,
I'm not that 101% in this case. Minilab chemicals behave much the same as single-use chemicals. However, it seems to be a better approach to replenish timely than to adjust filtration. In my experience, you will run into crossover filtration problems prior to getting a "too far out color balance". Dmax is usually my indicator, too. If Dmax is not dead black, I'll have to replenish CD.

In my understanding, a control strip is a well-known pre-exposed piece of paper that is analyzed with a densitometer. A test strip is more or less an indicator if something is ok or not. I sometimes use test strips to check if my BX is still ok (which is not that easy to determine as CD)

 

[edz]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
One of the first questions I have is about the duty cycle in question here.&nbsp; I do not *reguarly* process RA-4 paper, and when I do, it is a "small volume" run.&nbsp; I don't think I've ever produced more than the equivalent of thirty 8" x 10" prints in a single day.</td></tr></table><span class='postcolor'>
I don't either, so the question.. Its all low duty, sporatic processing whence my query about these chemistries.. as I mentioned 20l is twice a lot..

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
The second consideration *I* have is that my primary concern is quality, rather than economics.</td></tr></table><span class='postcolor'>
Of course... (and to have fun).. Lets face it.. If cheap was an issue it would all go to the drugstore chain where finished prints costs less than just my paper.

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
This discussion motivated me to visit Tetenal's web site.&nbsp; Glory!!&nbsp; Anyone who wonders if film/ chemical is "dead" should do the same -- they are putting a *bunch* of research into new chemicals, new materials, new processes.&nbsp; Interesting.

You spoke of "Tetenal's Ecoline BX-MR" chemistry.&nbsp; I couldn't find that anywhere, although that could easily be my fault.&nbsp; Their extensive caqtalog, in .pdf format, was not an easy one to navigate.
</td></tr></table><span class='postcolor'>
Its a newer Blix for medium throughtput. Did you have a look at the Ecoline family of RA-4 chemicals (Minilab):
http://www.tetenal.de/f_photo_mini_chemie_...ine_prod_uk.htm
The CD-SLR (developer) is 70 ml/m^2. They say for machines with high throughput but that's a nice low replentishment demand that seems right for slot processors.

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
Interesting chemicals here that I am NOT familar with.&nbsp; I note the trend to powder (pearl) forms of RA-4 chemistry (must have a very long shelf life) as well as a "rapid" form requiring 28 (!!) seconds of normal developing time.</td></tr></table><span class='postcolor'>
That's the amateur market, resp. press (to the extent that its not nearly now 100% digital) stuff. The C-41 Phototabs, however, I really do like!

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
Which all leads to: Where are your sources for the contemporay Tetenal chemicals?
- and where are you located?</td></tr></table><span class='postcolor'>
I am in Munich... and I guess I get stuff through various sources.

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
...I'll agree with that, but, mixing fresh each time MEANS a "new" batch, and although the "batch" to "batch" uniformity is very good ... there are inveitablly *slight* differences in color balance which - uh - irritate a perfectionist.&nbsp; "The same" also would neglect the effects of time in storage - even with measures to lengthen shelf life, this stuff DOES deteriorate- and, as near as I can tell, at a more or less "random" rate. </td></tr></table><span class='postcolor'>
The RA-4 process has, however, been designed to have a maintainable level of consistency... If not all the Kodak QC in the world won't mean anything other than that single test was OK but everything else was not.. same btw. with your "zeroing".. The commercial developers are designed to keep running for long periods of time and have been designed to "demand" a certain level of "polution".. that's why one uses starter for the initial bath (or one shot) should "old developer" not be available..

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
Intersting that you speak of "demand rates".&nbsp; What specific process do you use, and what equipment?</td></tr></table><span class='postcolor'>
I use all kinds of B&W and colour processes.. For film development its mainly between rotation in a Jobo Duolab (in the rotation part I use for C-1 the Tetenal Phototabs) or NOVA FP Dip and Dunk (the Press kits are good here).. For paper I'm quite biased towards slot processors.. alongisde the Duolab, I have a few Jobo Primas and a 12x16" Nova Club (basically a TriMate with built-in washer)... for large prints (16x20" and 20x24") I tend to use hand-rotated drums (one shot). Since colour printing is limited pretty much to 8x10" and maybe a 12x16" it goes into the Duolab (so the 12x16" colour are done "one shot" via rotation)

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
Anyway ... I'll "re-ask" ... Where can I get this new Tetenal chemistry?
</td></tr></table><span class='postcolor'>
Alongside Tetenal.. and Calbe in Germany.. you may want to look at Fuji-Hunt and Champion..

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
P.S. How do I "split" quotes like that?
</td></tr></table><span class='postcolor'>

Look the the [ QUOTE = ... stuff in the editing window..

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (edz @ May 14 2003, 04:44 AM)</td></tr><tr><td id='QUOTE'></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 03:36 AM)</td></tr><tr><td id='QUOTE'>
Which all leads to: Where are your sources for the contemporay Tetenal chemicals?
- and where are you located?</td></tr></table><span class='postcolor'>
I am in Munich... and I guess I get stuff through various sources.
</td></tr></table><span class='postcolor'>
Ah, Munich.

I've e-mailed Tetenal, requesting help for obtaining their products on this side of the "Great Pond".

Thank you for alerting me to the "latest" from Tetenal.

 

[DKT]

Here's a link to the Kodak chemistry site that deals with process control. If you go the processing manuals section, you can get to pdf versions of the Z books. They explain how to set up your process, use the control strips etc. and there's also info on that site about dealing with low volume usage for the chemistry.

http://www.kodak.com/global/en/service/che...hotoChems.jhtml

fwiw, control strips are pre-exposed film or paper from the manufacturer. they come in emulsion lots just like film does. kodak ships theirs same day packed in dry ice or packed with one of those frozen gel bags . you get them & store them immediately in a freezer, and every day you just pull out what you need. The box , comes with a reference strip that you read & apply certain factors to (for the emulsion of the strip)--these are the values you aim for and check your daily plots against.

KT

 

[edz]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 14 2003, 04:06 AM)</td></tr><tr><td id='QUOTE'>it seems to be a better approach to replenish timely than to adjust filtration.</td></tr></table><span class='postcolor'>My sentiment as well.. why also so-called constant developers and/or replenstishment of some sort too is appropriate to B&W chemistry.


</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 14 2003, 04:06 AM)</td></tr><tr><td id='QUOTE'>In my understanding, a control strip is a well-known pre-exposed piece of paper that is analyzed with a densitometer. A test strip is more or less an indicator if something is ok or not. I sometimes use test strips to check if&nbsp; my BX is still ok (which is not that easy to determine as CD)</td></tr></table><span class='postcolor'>This is where the Lici/Jobo ColorStar (and its Jobo's patent montebank mutation as Colorline] comes in very nicely. By examining the calibration prints made on the same batch (no need really for frozen specimens since the printing paper is not the same and one is looking to get good prints with a "wellknown" batch of papers and chemistry and not standardized process control) against a colour reference card--- a reflective colour densitometer is nice but not really demanded by this regime--- one can see monitor, control and adjust the chemistry accordingly.

 

[edz]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 14 2003, 05:46 AM)</td></tr><tr><td id='QUOTE'>Thank you for alerting me to the "latest" from Tetenal.</td></tr></table><span class='postcolor'>
What's also very interesting is the observation that all the NP ("No Plumbing" or waterless) sets are reserved for commercial and the amateur sets demand water.

Super-Stabilizers like Tetenal's STAB-WL not only brightens up the paper a bit and replaces the need for watering ("No Plumbing") but even, according to vendors, **increases** the archival qualities. its perfect for the 4th slot in a Duolab or Nova Quad and even the wash slot (instead of water) in a Nova Club or TriRapid.

The downside is that the typical unit of sale is enough concentrate for 100 liters or more.. which again.. looking at the replentishment rates that's a whole lot of stab.

Which brings us full circle, again, to the inital point of question.. How long can these concentrates be stored. A mini-lab may run through many liters in no-time flat but I'm quite far removed from being a "mini-lab"..

 

[Ed Sukach]

I recently (last week) opened a "reserved" set of Tetenal (JOBO) RA-4 Chemicals - Half-full bottles opened on 4 September 2002 and preserved with my dwindling supply of "Protectan" spray; stored at ambient darkroom temperature. All chemicals are *fine*. Test strips (ColorStar type) indicated *very little* sensitivity or color balance shift.

I *really* like the Tetenal chemicals - for both their longevity and results.