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Colour instability on 3202


Laci

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Hello everybody! We are geting the following strange experience: for each batch of prits we are sending through on a 3202 the very first print will get out a bit magenta while all the rest from the batch are a bit green (2% of +magenta is fixing the difference - however, we are concerning about this jump from the first print to the next and the rest) ... and this happens again and again anytime whenever is a couple of minutes breack between two batches of prints  ... and, also, this is happening on all paper types and surfaces even the dayli setup and the emulsion number change calibrations were made up to 0.0 correction value for each. If somebody can give us a clue it will be highly appreciated. Thank you very much!

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Hello Eugene:

I like your packet on color variation, EXCEPT that it says to dump chemistry if it is "bad."  Chemistry can be "bad," but it can also be "weak,"  "too acidic," "too basic," or "too concentrated/too dilute."

I have seen a lot of labs dump perfectly fixable chemistry down the drain.  Adjusting pH, specific gravity is not that difficult with a little bit of skill, not that this is the problem here.

Perhaps you should put a link instead to Kodak or FujiFilm documents on processing control.

I know labs that dump chemistry if it is sitting for a month.  All they would have to do to save it is empty it into tanks, try to keep all air out with floating lids, nitrogen gas, then adjust the pH back up re-dilute it in a month.

You can keep chemistry good for a very long time and fix just about any problem except for BLIX / BLEACH / FIXER a lot of it dumped into the developer tank.

That is the one big nono you really can't fix, that and letting developer oxidize to the point that it turns to tar (just letting it sit out in the open with no lid, not running control strips ever, letting the machine run until the prints literally "die" they don't develop the developer has gotten so bad.

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Maybe you could do it little write up XXLtdlab on how it's done?

Most of us are not chemists so for quickness it's far easier to dump a problem chemical rather than spend hours messing around.

But I am interested in how you adjust & monitor PH levels, specific gravity, concentration etc?

Also how do you know what the PH levels etc should be for each chemical?

Getting back to the original topic, the most likely problem will be a faulty green AOM driver. This controls the amount of exposure for the green laser.

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Topic starter (TS) never mentioned that his lab was stopped for a certain time so I thought that he has color variation problem during a daily work.

Of course if lab was turned off for month and after that it has a color variations - the TS should suspect a chemistry first and only after it seek for another suspicious part of a lab.

And all information how to determine what component is dead on my web site was written presuming that lab has a chemistry in perfect condition.

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I know its a bit of "back to basics", but why not run a control strip to check the chemistry?

It seems that lots of folks have set up labs, but have not wanted to pay for a densitometer to run them. In my mind, you CANNOT run a good lab without control strips and a densitometer.

you do not have to run the strips every day (like the old days), just once a week, or when ever you suspect trouble.

It really does make it FAR EASIER to sort out your problems.

All the process control info is on the Eastman Kodak site, and densitometers can be had on ebay for a fraction of their original prices. and any distributor who sells paper and chemistry should also sell film and paper control strips (if they are a worthwhile distribtor!!!)

sorry for the rant, but I feel better now!

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Mr. Noritsu:  Thought I was reading my own post.

What's worse, you can get a used X-rite 810 for under $200.  It's cheaper than a friggin' magazine to hold paper, a hollowed out overpriced plastic shell.

Running a control strip first thing in the morning *EVERY DAY* saves the hassle of having to redo a job because of a chemical mishap overnight.  Even with internal calibration strips, there are two variables:  The lasers and the chemistry.

With a control strip (unless you abuse them) there is only one variable.

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Maybe you could do it little write up XXLtdlab on how it's done?

But I am interested in how you adjust & monitor PH levels, specific gravity, concentration etc?

Also how do you know what the PH levels etc should be for each chemical?

Well, I don't figure the pH levels out for myself!  :-p

It depends on the solution, but some are sensitive to pH, others specific gravity (weight of a certain volume, which can indicate if the chemistry was mixed incorrectly, has too much evaporation), and now with volumes dropping, you have to be critical of percent utilization (percentage of the tank that is turned over every week, because if chemistry sits, especially without floating lids or nitrogen to keep air out, it will oxidize over time and stop working, at which point you DO have to just dump the thing.

As for not setting the pH values by trial-and-error testing, nor the specific gravity. . .  http://www.kodak.com/global/en/professional/support/techPubs/cis61/cis-61.pdf  This is Kodak Current Information Summary (CIS) 61.  It's pretty recent, and I do know sometimes the values change slightly as the formulae are modified improved.

Developer has to be BASIC (pH above 7.0 is basic) to reduce exposed silver halides to black metallic silver.  Solution has to be acidic (pH below 7.0 is acidic) to stop development (stop bath).  

Sometimes, solutions go out of whack on the pH and become too basic or too acidic, causing over- or underactivity.  A simple adjustment of pH can fix otherwise "bad" chemistry.

Just dumping some 28% acetic acid or another acid into the working tank can save hundreds of dollars.  Alternatively, potassium or sodium hydroxide (bases) are used to reduce acidity and make the solution more basic.

It really is a simple matter of adding it to the tank solution until the pH number is correct.  Formulae and a knowledge of chemistry speed up the process, but it needn't be complicated.  Probably quicker than mixing a fresh tank checking any one of a number of problems and remedying them (short of bleach killing the developer, total oxidation of the developer).

Specific gravity readings are a great way to determine the RIGHT amount of water to add to a tank that has had evaporation over the weekend.  Just read the specific gravity, of a properly mixed solution, and add water as appropriate to bring the reading back up.  Multiply by the number of liters or gallons in the tank and then add how many mL/ fl. oz. necessary to bring the specific gravity back down to the proper level (not much one can do to bring specific gravity up, without dumping chemistry and adding replenisher, this is a chemical mixing problem though).

What else. . . starter has bromide and chloride particles (silver HALIDES are AgCl, AgBR, and AgI, mostly the first two) that are similar to those left behind during reduction of halides to black metallic silver.  The ions reduce activity of the developer.  These are more difficult to measure, and involve specialized chemistry, not widespread, easy methods such as pH checking, specific gravity measures, but can be used in addition to control strips to determine the need to modify replenishment rates, see if a particular large batch of blank or fogged film/paper has affected activity, particularly important in developer(s in E-6).

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  • 2 weeks later...

Sorry ... I have to apologize because I haven’t mentioned that: the lab has been out of business for a few weeks and then recently moved into a new location where we had some accommodation troubles like we couldn’t get the proper room temperature (was going too low during the night and there were big variations during the day too).

I was reading this interesting debate regarding the chemicals, and I have to admit that there are some good points, but, just to "cool down the spirits": the chemicals are fresh and well mixed ... I agree that  most of the times we should start any trouble investigation with the control strip but no chemical problem will give one print a bit magenta and right after a few greenish and after 3-4 minutes all this happens again for the next batch of prints in the same way, and then again, and so on - the chemical troubles are giving consistent shifts in one direction and they usually go from bad to worst.

Anyway, thank you for all your inputs, however, even I was suspecting the Green AOM myself too, I preferred to wait for a couple of days and, well, after some intensive printing and yes, after, we reached to get an constant and proper room temperature in the place where the lab is installed, the color jumping has stopped, so it seems that we don't have to change AOM - at least for now.

I'm new to this forum but I will look forward to be more active, and who knows, I may meet you again on some other topic.

One more time: thank you very much!

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Yeah, Laci, that's an electric problem.

Of course, before lasers, that could happen with lightbulbs too. . . anyone remember condensation on printer lenses?

I hope I didn't come across as condescending.  A lot of people on here go "the chemistry's out of whack, so I 'll just dump!" whereas they're willing to learn how to program e-proms and CPUs, check voltages, amperages, resistance, write their own lines of code, anything with the IT, but nothign with basic school-aged chemistry?   8)

Good for you for being on the ball with the chemistry shifts, and bonus points for not calling it "pink!"

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