E6 chemistry question

Rob, I am sorry I have taken part of the stage from you. My apologies.

 

Ron, I examined at some images and did more thorough investigation of

the problem now I have more info to describe it. First let me

describe a typical histogram of the images in question. Each histogram

has a pattern that there is nearly nothing to the right 1/3 but has

nearly max value to the left 1/3. The middle 1/3 varies according to

the content of the image. I think this says low in exposure or not

enough development (too dense on the film). However if an image contains a piece of sky then the histogram does show some value to the

extreme right of the curve. This tells a lot about the contrast

problem as well.

 

I tend to believe the film was either under exposed or under developed.

I doubt it was under exposure as my camera is fairly new an is a

pro gear. The color balance problem may be caused by the fact the

film wasn't properly processed (or possibly not properly exposed).

 

Please see the attached image cropped out of an image which shows

a piece of sky and grass that is basically liveless. The original

scene was on a grassy hill full of sun shine and the grass was full

of spring colors.

DK, I think the gallon sized E-6 kit is slightly higher in price but

since it gives only a gallon so it is just about doubling the cost if

used one shot. I remember the old kit I used long time ago was quite

potent to process a few rounds for many rolls so I assume I could

get away with maybe two shots? If so then the cost is about even with

the 5L kit.

 

I really don't have any methodology in terms of testing with control

strips other than do it the standard way with some tweaking here there

to find the best setup and process. I have just about used up the

entire 5 liters and am still very lost.

 

I agree with you that the gallon kit is among the best E-6 chemicals from Kodak. The 5L kit is probably a hack or a rip off. I am sorry,

I love Kodak stuff but I really have some opinions about the 5L kit.

 

The problem I am encountering is not simply a 10CCM adjustment that

can fix. Another possibility of the problem may be in the CCD scanner

that I use. Well, it was a $2000 medium format CCD scanner at the time

I bought it new. It is not much used to have the CCFL light source

exhaused most of its usable lifespan yet.

sorry, dave, I meant the 5 liter kits were easier to mix than the previous one gallon set. first off--you had to dilute the reversal bath--no big deal, but in the end you were left with all these half empty little bottles to toss out. Then, for some reason, it seemed nine times out of ten, the bleach would have this crystalized sludge in about a third of the bottle--you had to first heat the concentrate up a bit and then while mixing, use a stirring paddle to beat the living hell out of the crud to break it up. Our processor (Wing Lynch) uses 5 gallons of the chemistry--we'd mix up a couple of gallons a week, endlessly topping off the tanks. Sometimes, we'd set the worst bleach bottles aside, and dig around in other kits to find ones that weren't so bad. Then, as the stock was dwindling down, you had all this solidified bleach to try to mix up. Lastly--we had to adjust the pH in every mix with sodium hydroxide. We still do this with the 5 liter kits, but in much smaller amounts. Like 10ml or so--not the 25-40ml needed before. I can remember adding even more, like 70 to get the plots right.

 

The best E6 chem, is repl. and the type mixed with starter etc--to get the speed & contrast right in a seasoned soln. One-shot is tough, because there is almost NO control measures beyond pH adjustment and dumping your chem & starting over. You can mess around with extending washes and raising & lowering wash temps, or changing first dev times--but in the end, if it comes down to sp. gravity adjustments etc--this usually means starting over or that you've screwed up your film anyways. because the chem is gone--it's one-shot.

 

The 5 liter kit is strictly one-shot. There might be problems reusing it, because it's not like the replenishable chemistry. The color dev, afaik, is used to completion in the process, and is triggered by carryover reversal bath. There used to be a wash between CD and conditioner--this has been replaced now by pre-bleach. The stabilizing action occurs in the pre-bleach and is triggered by carryover CD. So, I don't know for a fact--but I imagine reusing this chemistry would be tough on control without figuring out some sort of repl. scheme. On top of that--as you use the process, the activity will drop off and will need to be repl to reach a working state (seasoned). If you're not running control strips, you may have to live with varying speed & color etc as the process declines, and you'll have now way of tracking the repl amounts beyond eyeballing the film you just ran. The first dev times will change. It may actually run less contrasty, less hot--I don't really know. Kodak would probably advise you not to do this. The bleach would probably need to be aerated as well, if re-used. Fix would probably be okay. Final rinse is almost like photo-flo now, seems best to use it one-shot.

 

As for the cost--well, I don't think the one-gallon stuff is sold as a kit anymore. I think you buy it separately. Last I checked, it was almost 85 bucks street price versus maybe 40-50 for the 5 liter kit. It's the same as the 5 liter kit in regards to pre-bleach and final rinse and the newer sequence. Where I work, we buy large amounts of kodak chemistry & products across a gov't system--as a result, we do this on annual bids & contracts. The cost of the hazmat fee on the E6 kit is almost as much as the unit cost. The worst part about it, is the packaging. You order, say 50 kits, and then have to pay a hazmat fee for each, and your total doubles. Kinda like the downsizing of the 100 sheet 4x5 film boxes to 50. You have to order twice as much packaging to get what you need, and it winds up costing more than it did before.

 

 

Rowland--I've heard that from others. Had a tech complain to me that if they ran their process like kodak suggested as far as control plots--the fujichrome would like lousy. everyone runs kodak control strips though, even with fuji chemistry, so we've been getting the full range of tips as far as control goes. some are kind of unorthodox and involve treating the 5 liter kit as if it were the "real" E6 chemistry and seasoning the developers. Others involve adjusting the first wash temps beyond what kodak would recommend. Another involved a mix of what you might call aggressive sp. gravity correction on the color dev mixed in with a seasoning step. In the end--what worked was a hybrid of what Fuji techs had told us several years ago--extending the final washes, with slight addition of sulfuric acid to the color developer. Which in a way is bass-ackwards to what the Z-book would say to do for the plots, but it worked in bringing the plots together well within tolerances. What produced an acceptable chrome was to filter back with CC's in the end, which I think is pretty much par for the course as far as chromes go anyways. +/- 10CCs is in-control, but it's just annoying to have to do it with every stinking emulsion batch for years on end. You'd think maybe one, would be 2.5 pts or maybe 5, but no....sometimes they're even 15-20 pts.

 

What had happened--was that in trying to correct for "real" film--at the expense of the control strips--we ran into crossover where the higher values went green and the lower and midtones went magenta. Which meant that sometimes, the film looked okay, other times, it was freakishly "okay" in that the highlights were split. After several years of trying to deal with this--think we're going to switch back to EPN and EPY.

 

good luck all the same to the rest of you--me, I send my E6 out. I figure, why torture myself on my own time?

 

as they say: Opinions expressed in this message may not represent the policy of my agency.

 

 

 

 

Don;

 

Nitrogen is less dense than Oxygen, but with about 3x the partial pressure, it is just about as likely or more so to stay in the bottle as it is to be displaced by air. At worst, carbon dioxide will replace it and that at very low concentration.

 

Dave;

 

I see what you mean. The mid to low density range is rather magenta on my monitor. This looks like crossover or soft magenta toe which is either bad MQ or bad color development. Since there are no whites for comparison, I can't tell if it is retained silver, but silver halide and silver can appear like that in highlights. Are whites white?

 

DK;

 

Yes, why do E6. But then it is fun too. I do both E6 and cross processing and find I have more fun from the cross processed Ektachromes than I do from the normal Ektachromes. I think that the need to make the transparency films all look alike or similar has led to a proliferation of tweaks to the process to keep things going. As I have said before, negative films are easier to design, the processes are more stable, and the results are more uniform with higher quality.

 

This just seems to emphasize those qualities of negatives that I like so much, and emphasizes again those problems of transparencies that bother me. See the other thread on keeping of film. I find that negatives keep well, while all but Kodachrome slides fare poorly over the years in the dark.

 

Regards.

 

Ron Mowrey

well, why do E6? sometimes I rue the day we started doing it in-house...however, it looks like in the next few years, as E6 processing opportunities dwindle down in my area could be a good thing after all. I have found the cost issue to be a moot point. It costs us about as much as our cost at the Q lab nearby. It's about even, and as far as time goes--we're only half mile away maybe, so that's not a huge deal. OTOH--we can do a shot, run half the film, make adjustments if needed, run the other half, break the set & move to the next shot. We can push & pull in teeny amounts to tweak the contrast and such--and get much quicker feedback in this way than with dealing with a lab.

 

As for longevity--we don't shoot color neg. I work in a historical preservation system--the archivists & conservators don't like color neg too much. B&W sheet films and some b&w rollfilm are used for the longterm file. 4x5 transp. and smaller formats for "illustration" purposes--i.e. not longterm record. There are microfilm labs in the archives as well that deal with public records and the like--I expect the microfilm to outlast the whole lot of the other stuff.

 

There's an archive that houses the records and large collections of various negs and images. There are cool rooms and cold rooms and such. In one of these rooms, we (I work for a museum in this system)--have several thousand old slides--kodachromes, anscochrome, ektachromes etc--dating back to the mid 40s. The Kodachromes have fared the best. For the most part, these slides are rarely used--mostly to make slide dupes or scans. They live out their lives tucked away in baked enamel drawers in the dark....

 

it's my understanding--not being an archivist or conservator--that for every ten degree drop in temp, the life of the film is doubled. Basically, in the best scenario--you'd freeze your color film in a pretty dry environment, free of ozone, peroxides, formaldehyde etc--using PAT approved enclosures and leave the film there forever--trying to maintain this temp/rh within maybe +/- 5% rh, and a couple of degrees. This way, you'd get thousands of years. If you look at a film like tri-x for example--as a b&w acetate based film--the LE (life expectancy) is pretty short actually. Around 50 yrs or so for normal office type room temps. It's only with the polyester based films, even at mid range type room temps & rh that you get into anything approaching an "archival" media. Color is just not there--not unless it's in pretty cool/cold & dry, and kept in the dark.

 

oh yeah--if you use it? it's not going to last as long as the stuff tucked away in deep storage.....then again, most people could care less about what comes down the road 50, 100 yrs from now. all in all though, color neg will still probably outlast most digital files. seems a shame with all these weddings being shot on digital now over color neg....just means in museums like the one I work in, in 50 years, they'll be copying faded inkjets and dye subs because the files are long-gone. It's already happening--in the past 5 yrs, I've seen more & more inkjets coming in as "photographs"--with no digital files anymore. As a photographer in a museum--can't tell you how depressing it is to shoot 4x5 chrome & b&w film of a crappy inkhjet for the "longterm file".

 

oh well, that's it for me--my opinions only/not my employers.

I used to run dye stability tests at EK. I know what you are talking about. Heat, humidity, light, and oxygen are the culprits. Formaldehyde is not a problem with processed film. It only hurts unprocessed film. Acidic or basic environments are not good for some photographic materials. Some like to be slightly acidic or basic. Iron contamination can hurt color films. The ferric ion can reduce dyes to their leuco form and then they can 'decouple'.

 

The lifetime of B&W films are long. Fifty to 100 years or more. Second comes Kodachrome and Color neg. I have good examples that are 50 years old right now myself that test as being near perfect. I have family B&W negatives that are nearly 100 years old. Most are in the range of 70+ years old.

 

Ektachrome fares worst. They are fading - turning red - after only 20+ years. This includes E1, E2, E3, E4 and E6. (well, I have some E5 and they are bad too)

 

Supra Endura paper is reputed to have a lifetime of 200+ years according to EK.

 

Electronic images on CDs and other media are reported to have a half life of about 10 - 20 years with todays technology. That is pretty short when compared with conventional photographic materials. There was an extensive article about it recently in the business section of our newspaper. Seems as if no one is addressing that one very earnestly IMHO.

 

Ron Mowrey

Dave,

 

Just a few points on your processing with the Kodak 5L kit. From reading your posts, I think I see a few errors in your methodology. First you indicated that your kit has been opened for 9 months. How have the chemical concentrates been stored during this time? Second, you did not mention how long you kept mixed working solutions around. Third, you said you were mixing 500ml at a time. Mixing up chemistry in this amount can be tricky and the need for extremely accurate measurements is necessary. I usually consider 1L to be the smallest I�m willing to try. Fourth, for rotary tube processing, Jobo recommends 7:30 for all Fujichromes (16% over other E6 films) except Astia at 7:00 (10% over other E6) so processing these two films together is not recommended. Also, it�s not recommended to process Kodak and Fuji films in the same run.

 

I believe you are experiencing a processing error of some kind, not a camera or scanner one. I use the Kodak 5L kit with very good results, however, I have only used fresh chemistry and have a very consistent processing regimen.

Ron, I kept the chemicals in their original bottles tightly capped.

I understood this could be a problem down the road especially toward

the last few batches. 9 months was a long time too long to be reasonable.

But I had the problem from the very first batch when the chemicals

were fresh. Well, I had the first developer for 6:30 the first time.

The film came out too dark. I thought it was lack of exposure. I tried

another batch. Better but still not good. Then I realized I needed more

first developer time. I set it to 7:00, then 7:15 then 7:30. There was

some improvement but still not quite right. I started to question

the E-6 chemical.

 

I used the mixed chemicals right after mixing. They were fresh with no

delay. In my recent batch I did mix an Astia with a Velvia as an

experiment to see if the Astia would come out too light. No... But

the chemicals might have been too aged for the batch as they were

from near the bottom of each bottle.

 

You have a good point here about mixing 500ml working solutions.

It could be the problem. I use a 100ml and a 25ml measuring plastic

beaker from JOBO. For mixing a 500ml working solution it takes 12.5ml

of reversal bath concentrate. This is the hardest part. It takes

23.5ml color developer B and 35ml prebleach concentrate. All other are

not hard with my 100ml beaker. I think I was careful enough to be

as accurate as possible. But I could be wrong as for E-6 a small

error might mean a disaster. I'll try to mix 1000ml at a time next

time. BTW, I have not mixed Kodak and Fuji chromes in processing.

I will try some Kodak films sometimes.

 

I am still at a loss of what exactly I did wrong. I am attaching another image as another example. The image is much darker than I

thnik it should be.

 

DK, thanks for your detailed explaination of how gallon sized E-6

chemicals are difficult to use. I think I will try again with another

5L kit before attempting the gallon packages. Unless I have good skill

and experience and the needed volume of films to process I would be

looking for more trouble.

 

BTW, I processed 2 220 rolls with 500ml working solutions. Is this

too much for the soup? Maybe this is the problem.

Dave;

 

Your last post looks correctly exposed except the rock shadows are just a bit blocked up, but fixing that would wash out the sky and sea. It might be contrast alone, but again the soil appears too magenta indicating soft toe.

 

Have you considered that it might be the film. There was another post about some recent problems with some Fuji, and I refer you to the problem they had about ten years ago.

 

Try sending out a roll and see what happens.

 

Ron Mowrey

Ron, for all the slide films I have processed with my 5L kit all

resulted dark images, except very few that were probably over

exposed. The 2nd image I posted had the scanner exposure adjusted to

push the histogram toward right. It was really the same as sliding

the middle pointer of PS "levels adjustment" toward left. While the result looks brighter it does not have the color dynamics that I expected. It is still an image too dark.

 

I will try some Kodak chromes. I definitely need to get a fresh

set of 5L kit again. I may send one roll out for comparison. I'll get

some fresh films right out of my local pro shops rather than from my

fridge. I'll check my cameras to find any possible metering malfunctions.

 

With all that I should be able to rule out all other factors but

focusing on processing issues. I am still inclined to believe that

the 5L kit is responsible for my slides being too dark. I wish to

fimd myself wrong. Thanks a lot for all your replies. They are indeed

most invaluable to me and everyone else too. I will report back when

I have results in the near future.

Dave;

 

Thanks for the feedback.

 

I wish I could help more. I have heard a lot about problems with both Fuji and Kodak E6 products on this forum. I do work with reversal, but not enough to be a real expert IMHO. I hope that there has been nothing 'broken' in E6 or with the films lately.

 

Good luck and keep in touch.

 

Ron Mowrey

Rowland--you might find some of this interesting. I don't know if you're familiar with the Image Permanence Institute at RIT? I've been to a couple of their archiving seminars in the past--they have alot of good publications, and some of them are available online now for free. Unfortunately the color film guide is not, though. Check out the software download-- the "Preservation Calculator" and it's accompanying pdf pamphlet, "The IPI Guide to Acetate Based Film Storage". Also, there are some new software guides on here now--dealing with mixed media storage , and a good pdf guide to digital output materials for consumers. The scrapbooking section is very good as well, if any of you are involved with this kind of thing. Very informative reading about the Photographic Activity Test and what consumers should look for in safe materials as fas as "archival-ness" goes.

 

BTW--check out the Stored Alive interactive, for examples of light & dark fading.

 

http://www.rit.edu/~661www1/sub_pages/8contents.htm

 

I mention this, because the lifespan of film is not just the image--but the base material as well. Obviously a base like nitrate, was highly unstable--but we have nitrate negs that have fared better than the earlier "safety base" acetate negs--which have shrunk & in some cases buckled the emulsion off. I've opened old filing cabinets that stored negs, and the smell of the acetate based film would about knock you over when you opened a drawer. You'd have a headache for the rest of the day....and that's with "safety film". The base that almost all rollfilm is on to this day. Sooner or later, time will catch up with that stuff.

 

my opinions/not my employers.

Dave--looks to me like a contrast problem in part, but it's hard for me to evaluate color on a computer screen--sorry. I've had some real tough times over the past couple of years trying to get our fuji to run neutral. Today, my boss & I were talking to a q-lab tech who told us fuji just runs magenta-red. Which, according to our in-control Kodak strips, would pretty much be case in point.....

 

That said, here's some stuff to try if you feel like tinkering: IF your film is running magenta, try adding sodium hydroxide 5N to the color developer in small increments. This will be tough if you're mixing smaller quantities. Right now, we're adding 10ml to the 5 liter amount. You can get this in dry form from kodak and carefully weigh it & mix or get in a set liquid dilution from chem supply houses like Fisher etc. *Be careful when you use it*. Fuji runs magenta-red, if the color dev is too acidic. Green-cyan, if it's too alkaline. You can also push it to the other bias with sulfuric acid--get this premixed at 5N from the chem supply houses as well. It's possible to extend your final washes--and wash out some sort of magenta dye in the film. You can also soak it out in final rinse, not unlike the magenta stain that comes out T-Max films in hypo clear. You can vary the first wash temp a bit to effect color balance as well. If it's a bleach problem, you should be able to rebleach in fresh soln., or even aerate the soln. as well, and correct. There could be multiple problems going on though, which is why a trial & error methodical approach is helpful, not much fun, but that's the way it goes.

 

hope this helps.

Dave,

 

According to Kodak's E6 troubleshooting diagnostic chart it says:

 

high contrast with sharp density gradations between highlights and shadows can be either First Developer time too long or Color developer too dilute.

 

Of course this applies if you in fact have a contrast problem, hard to tell from the scan

DK;

 

Thanks for the information. I did so many dye stability tests that I'm frankly tired of them!

 

I know the effects of light, heat and humidity on C41 materials and EP2 materials from 1965 to 1990. I ran tests for many of those years and kept track of them afterwards.

 

I am familiar with the need for a stable support. One that does not crack, craze or explode. Acetate film support up to 50 years in age seems to be ok kept under ordinary conditions as does FB and RC paper, although, IMO early RC may be marginal from some manufacturers.

 

EK spends a lot of energy on dye stability and support stability.

 

Tests include light, dry heat, and wet heat. Reports have been made at SPSE conventions on the results of some of those tests. The culmination of these are the new Endura papers with an expected life of over 200 years. That exceeds some B&W estimates.

 

As I said above, these factors as well as oxygen affect dye stability, indeed the stability of all photographic materials. I am just happy that I have 100 years or more of photographic records of our family going back to the Civil war.

 

I have a photograph of a great great grandmother who was a personal friend of U. S. Grant and the photo depicts her in her dress that she wore to the inaugural ball for Grant. That is a piece of our family history. We have a piece of the dress as well.

 

I am quite aware of history and its value. Good stable photographs are part of that history.

 

Thanks.

 

Ron Mowrey

Hi Rob, thanks for doing the research for me to help.

I do observe that it is in part a too much contrast problem.

And I also feel it is an image too dark issue as well. One of

the reason for too much contrast I agree is probably too long the

first development time at 7:30. I don't understand why JOBO says it

needs to be increased from the standard 6:00 to 7:00 or 7:30.

I probably should lower the rotation RPM of the JOBO processor a bit. At 75 rpm I just feel it is too much (constant) agitation. It is

strange to have to increase time while having a constant agitation.

It doesn't make sense to me.

 

Hi DK, It is true that it is hard to judge the color balance of an

image provided that yours and mine monitor can be very different

in color alignment. I think once the film is not properly processed,

which is shown on its abnormal density and contrast, the color can be

off a bit. It may not be too meaningful to determine what the problem

is by looking at the image on the monitor. BTW, it is funny that my

6x7 images all look not very sharp on my monitor. But when I print

them on my inkjet printer they are very very sharp.

 

I think I will not take the route to try tweaking the soup by adding

additional chemicals. A stable and repeatable E-6 process is highly desired. I do have a very good PH meter that I once tried and determined too costly to keep it up daily but only used occasionally.

I would like the density to be correct (an even distribution shown

on the histogram) then if there is a color balance issue I can always

correct it with photoshop. If I run a large production lab and use

large tanks of chemicals then it will make very good sense by tweaking

the soup to keep it in optimal condition.

 

Ron, I really wonder why JOBO says I need to increase the first

developer time. I agree it may have something to do with the contrast

problem. I increased it to 7:30 trying to reduce overall density but

it also increased contrast.

 

Anyway, I used to shoot exclusively C-41 only except long time ago.

I switched to chromes to look for better color saturation and finer

grain when shooting landscapes. I think I do like the colors and

the grain better but all that is ruined by the density and contrast.

It's already 9 months passed and it is not solved yet. Comparing

with E-6 process C-41 is really nice and easy life.

 

Dave

dave--we don't use a pH meter. don't even own one...for one thing, they're prohibitively expensive for our sort of use. I'd rather put that money towards something else, to be honest...that said, we're doing this based on control strips. We run a strip with each run, or else do one with the first run of the day to see how things are going. If there's a problem, we'll just run control strips 'til it's hammered out.

 

Here's my suggestion--get a box of control strips. Get the short Kodak strips, they run about 50 bucks for 50. They ship them same-day in dry ice. Keep 'em in the freezer until you need one. They come with a reference strip. If you had a densitometer, you would read this strip & apply correction factors--given out by Kodak both with the particular emulsion batch of control strips, and updated on their site as a result of audits of the Q lab system. The point is to have a realistic reference for everyone to be working against. These new values, become your processing "aims"--that you track the control strips you run against in control plots.

 

Okay, what if you don't have a densitometer--this would in itself be overkill and cost prohibitive for most home processing. You can use the reference strip on your lightbox to eyeball gross density and color changes. The strips are pre-exposed grayscales really. There are parts of the strip, that your eye won' be able to really tell much about. But the midtone areas, and even parts like d-max and d-min mightbe of some use.

 

If you choose not to go this route--then try making your own test strips---shoot a graycard and bracket a bit on either side. Blow off a blank (d-max) frame or two. Maybe even do a d-min frame or two. Shoot several rolls at the same time & throw them in the fridge. Make sure they're all the same emulsion batch, all the same date. I'd probably do all US--no gray market. Fuji US starts with a 74101 barcode number. If there's a 90, 9021 etc prefix? This is gray market. Buyer beware. Kodak has a "made fresh for the US" logo.

 

Alright, take a roll of this to a local lab you trust. Run it. Run another roll in your process & compare. The lab, if you trust them--will be your reference. If you've written down or remembered your normal exposures, and the brackets, you *should* be able to figure things out a bit & extrapolate film speeds (EI) and color balance etc--even fine-tune your first dev time. One thing you could do, is figure out how many frames it takes for your simple test--and repeat these over & over on a single roll, that you can do clip tests of instead of burnng a whole roll.

 

Boring? yes. But it's about the only way you can get a handle on the control of the process. The one advantage making your own test strips will give you is in that you'll be using the same film you shoot with. Control strips don't often match the "real" film, as much as show the general health of the process.

 

FWIW-- I've always wondered about jobo's recommendations for first dev time as well. I have two thoughts on this--one, could be a problem with the chem oxidizing in the run itself, from the skimpy amounts used in their tubes and the constant rotation. Secondly, chrome films are often rated high for most people. I've never shot Velvia at 50, more like 40. Same goes for Provia, it's more like 80 for me. I've always assumed Jobo was giving the film a slight push to account for this real speed. Just my opinion though--I'm not a jobo user.

 

Good luck & hope this makes some sense.

btw--when you run the tests or the control strips, make sure you either run them alone, by themselves in the same orientation in your tube. OR--run them in the same spot with each run of film. The fact of the matter is, that there are often processing variations within the tube itself, and even with other amounts of film, that will throw the strips off. It's important to do the tests in as close to the exact same way everytime. In practice, the plots don't really measure the same from run to run or day to day--they cycle up & down a bit, in random fashion almost. If you begin to plot the same way for a few runs in a row--they call this a trend, which is usually not a healthy sign of things to come. A process that's actually in-control, will be as much as a half stop plus or minus in film speed, and as much as 10 CCs in color. Just as long as you're consistently within the variables, you're okay.

DK, if I were to run a commercial lab then I would definitely keep a

ph meter up and ready to put it to work every day. It can be very

dependable to keep the ph value of each chemical bath in check.

With a ph meter working and control strips run daily (or even shorter)

best quality work can be achieved without too much headache. Well,

the headache is probably in keeping the ph meter in prime condition.

That is not trivial to me.

 

I do have a very good Macbeth digital color reflection/transmission

densitometer that works well. I have never used any control strips

so far in my home lab. Thanks for the info about it. If I were to

run a commercial lab I think your advice is certainly the best and

with the instruments I have I am sure I will sort out all the myths

and get good results there. But my home lab is really a hobby lab

that does not have any volume. I may run one or two batchs of films a

month in summer but much fewer in winter. For such small volume it

would be an over kill to get into the kind of tweaking your are talking

about.

 

But I think I got a real problem that I have no much clue of what

went wrong. So I probably will do as much as I can to trouble shoot

the bug. I may not go too deep into what you suggested though. It

would not be practical for a home hobby lab to get that far.

 

BTW, there is a possible cause of problems in my JOBO ATL-2300.

Whenever the processor is used it needs to go over a cleaning (rinse)

cycle to flush and clean the processor after the final run of processing. It prepares the machine for the next run in future

time. Well, after such cleaning cycle there is always some residue

water (about 20 or 30 CC?) of water remaining in the hoses between

chemical supply bottles and the processing drum. If I run a batch

of film with 500ml or even less chemicals the water will actually

dilute and possibly contaminate the chemicals. This only happens to

the first batch after a cleaning cycle. All following runs will be

fine. Unfortunately I rarely run more than one batch at a time.

This really adds another variable into the complex problem. JOBO

says nothing about this bug of their machines. I don't know if it

is a real issue or not.

 

Thanks for all your input. Have a great weekend.

 

Dave