</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.
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.
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.
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?