Nova Monochrome Uneven Development

[Dave Miller]

Ryuji,
My point was that I did experience the uneven development Mattg and yourself refered to, and my solution to its eradication was to follow the equipment manufacturers instructions, it was that simple.
I have since suggested that others pitch in with their experience since it is perfectly possible that there are several problems with multiple solutions at work here.

 

[pentaxuser]

Mattg. Once you have throroughly cleaned your slot, I'd be interested in what difference that makes.

As we can then rule out gunge as the problem it would be instructive if you can then make a print using the agitation that Dave Miller uses and Nova suggests, then one using simply the back and forth movement with no lifting circular motion and finally one in which you simply leave the print in the slot with no movement which might result in the local exhaustion problem.

OK this may result in two ruined prints but give you some peace of mind as to what does and doesn't cause the problem and may advance our collective knowledge.

In the meantime I think that Dave's suggestion that all Nova slot processor users pitch in with their experiences pertaining solely to this problem would also be very useful.

One of the issues with resolving problems via the internet is being sure that the "method for finding causes" is properly controlled and of course it cannot be but to use an analogy "if there are enough swallows, then we may be able to conclude it's Summer" and draw some conclusions while accepting some users' experiences will be different.

pentaxuser

 

[Matthew Gorringe]

Thanks for chipping in Dave,
I'm aware of the Nova insructions on agitation and have been following them as a matter of course with FB paper, although I was a bit lazy with RC (if you see below I confirmed last night that there is no problem for me with RC). While I ran the clip across the top for the example scanned, I sould have said that I always do the circular motion for the first 30 seconds, even with RC.

I do think that agitation is part of the problem though so it's good to hear other people describe what they do. Believe me I'm not being defensive, I want any other suggestions that could help. Dave, is your processor the Monochrome with the V shaped slots, curved, wall-of-a-dam type sides and waffle pattern plastic?

During my testing to eradicate the problem I've tried a lot of different variations on agitation from lots to little with a lot of different patterns in between. Once the lines appeared on FB paper I have been very conscious of not merely sliding the clip across the top. Of course the ideal way to agitate is in a random manner.

Last night didn't help at all, I used the bottle brush but without emptying the tank of it's reasonably fresh (1 day old developer). I also cleaned out the stop and fixer slots, again without emptying. BTW this tank is only 4 weeks old and it was emptied and rinsed with water only two days ago, it has processed 6 8x10 sheets since then.

This made no difference that I could see. I exposed 9 half-sheets of 8x10 MGWT FB and one sheet of MGIV RC to get a medium grey (as indicated on the analyser); to see the pattern clearly the depth of grey tone needs to be right in the middle of the scale. No negative in the enlarger and defocussed.

I then developed the sheets trying a range of different development times (2min-4min) and agitation methods while brushing out the dev. tank every two or three half sheets. I made every attempt to keep the emulsion side of the paper off the waffled surface but I don't think I was 100% successful.

The lines appeared on all the FB sheets where I'd given significant agitation. By doing the constant tone sheets I was able to see that the problem is worst opposite the clip and spreads from the middle of the sheet down so it's reasonably wide at the bottom; it forms a triangle.

The one RC sheet showed absolutely no evidence of uneven development. It used similar agitation but a shorter devlopment time in line with Ilford's recommendations.

I tried three of the FB sheets with very little agitation; lift slightly and side to side every 15 seconds. There was really very little movement involved. The lines dissappeared but the waffle pattern appeared, less noticable than the lines and spread more evenly over the half sheet.

There seemed to be no difference in the patterns between 2 and 4 minutes dev time which was tried with each agitation method, not the RC paper though.

Here's what I think, I haven't completely discounted Ryuji's solution because I haven't yet emptied the processor and cleaned with water and a bottle brush. However it seems unlikely that if I cleaned the processor as Ryuji does with the dev. in situ and still get the pattern that I will solve it by cleaning.

I think the problem is one of two things, heating up the emulsion during agitiation or, more likely, the waffle pattern making differing amounts of developer available to the print where it presses against the pattern. The lines could be caused simply by the clip returning the print to exactly the same height each time you stopped agitation, even for a few seconds, while the horizontal position is continuously variable. The reason I think it's not likely to be agitation heating up the emulsion is that with the consistently exposed sheets of paper I can see the pattern as underdevelopment, not over development.

Tonight I will do the following:

1. Empty the tank and clean all three slots with warm water and bottle brush together (I've misplaced my instructions but I think Nova say not more than 30 degrees c max).
2. Mix fresh Cooltone developer, try it in tray and tank, side by side.
3. Mix fresh Dektol, try it in tray and tank side by side.

Obviously I'm getting frustrated and wasting a lot of expensive paper doing this, if you can describe your agitation procedure here that might just help.

Thanks very much everyone, Matt.

 

[Ryuji]

I think the problem is one of two things, heating up the emulsion during agitiation

This is unlikely.

or, more likely, the waffle pattern making differing amounts of developer available to the print where it presses against the pattern.

I doubt it. If this were the case, prolonged development with additional agitation would eliminate or at least greatly alleviate the problem.

If you see the lines mainly near the bottom of the slot, and not near the top, I wonder how thoroughly you could rub the slot in the area where you see the uneven development. To make it more certain, I suggest to take the solution out to vessels and then clean inside slots using the brush (with a long handle so that you can reach the bottom of the slot) and water. You don't need to use force to clean it but the surface has to be thoroughly rubbed off.

I do this while the developer is in place, but I do use a very good brush made to clean burettes. It has just the right level of tight fit in the slot, and the brush is attached to a very long wire support so that I can insert the brush to the bottom of the slot and clean that narrow end very thoroughly. You can buy these from scientific lab suppliers. Prior to this I used a tooth brush attached to a custom extension handle, but this wasn't very effective. Bristles are too stiff and too long to reach near the bottom of the slot. Plus, you'd need a much bigger brush than a toothbrush because the area of slot inner surface is very large. Washing brushes I found at supermarkets were not satisfactory because the brush was too soft and low density and also the wire and handles were too short to reach the bottom half of the slot.

Good agitation technique is certainly important, but using clean slot and fresh developer, I can get defect-free prints with not much agitation (a few up-downs every 30 seconds with 90 or 120 seconds development at 20C). When the development-inhibiting stuff builds up on the slot inner wall surface, increasing agitation to the level exceeding Nova's recommendation and using circular agitation does not completely remove the uneven development. When this happened, when I cleaned only half of the slot, I got defect only in the uncleaned part of the slot. This was one of the reasons why I came up with my recommendation to scrub the inner surface of the slot periodically.

 

[Matthew Gorringe]

Some success but...

This afternoon I cleaned the three slots with water and a long brush.

The brush I've used is a long handled bottle brush that I've taken to with a pair of scissors, it is not ideal as I can't get it into the corners because they're tapered and I am afraid of stressing the unit by trying to get it right down. I probably miss about an inch off the bottom but get any area that an 8x10 touches. Thanks Ryuji, I will find one of those tools and use it.

The pattern I previously saw has not appeared.

This is what I've done tonight:

1. Mixed fresh Cooltone at 1:9 21 degrees.
2. Used in in both Nova and tray concurrently
3. Used MGWTFB first, exposed as last night. Dev time 3 minutes. Both sheets show significant uneven development. The sheet processed in the tray was rocked continuously but is much worse than the Nova processed sheet. Although the Nova sheet was not evenly developed the pattern I had previously seen was not present, it was agitated every 15 seconds or so after the first 30 seconds.
4.Same test as 3 but extended the devlopment time to 6 minutes (one minute more than Ilford's recommendation). Again both sheets showed some, but much less, uneven development and again the tray developed sheet was much worse than the Nova sheet. Again I saw no evidence on the Nova developed sheet of the pattern I had previously seen.
5. Gallerie. 6 minutes. Woefully uneven devlopment on both sheets , again the Nova much better than the tray. Again no evidence of the pattern I saw previously.

The uneven development is very surprising considering I've been using fresh developer each time and have made prints with lovely solid blacks without any trouble before I noticed the pattern that prompted me to do this mid tone testing.

I'm halfway through the session and have just emptied the whole unit again, cleaned all the slots and am about to make up some Dektol 1:2 to see what happens when I repeat what I've just done with a different developer.

 

[Matthew Gorringe]

Repeated the same test with Dektol 1:2. Dev time 3 minutes. Both MGWTFB and Gallerie much more evenly developed. This time Nova slightly better than tray. I'd say they're so even that I'd never have noticed anything if they were proper prints rather than flat greys. I will wait until all of these tests are dry before trying to work out what it all means.

 

[Bob F.]

Three mins in Cooltone with MGWT-FB sounds like it might be too short as both that developer and that paper both require longer than average time to achieve full development - that might explain why the Dektol versions were more even as it probably needs less time for full development that the Cooltone. You tried at 6 mins too, but at what temperature? The Ilford times assume 68F/20C. Much lower than that will effect speed of development.

Did you try the "first emergence" method? Put the print in the developer and note the time. Wait until the shadows just start to appear and note the time. Continue to develop for 5 times the difference. For example, if the shadows start to appear after 40 seconds, continue to develop for a further 200 seconds (3m:20s). This will ensure full development regardless of the temperature of the developer (within reason). You may find that 4 times is sufficient, but try 5 times at first to err on the safe side.

It looks like the cleaning has solved the banding problem however, so that's a good thing! You just need to ensure you are getting full development now.


Cheers, Bob.

 

[Matthew Gorringe]

Hi Bob, 21 degrees c, first immergence at about 45sec. 6minutes development almost as uneven as 3 minutes. I'm used to using an immergence factor as I have been using Gallerie until opting to give Warm Tone a try.

Previous to this testing I had made some good prints (apart from the pattern in the sky) that appeared to have lovely blacks, these were devloped for 3 minutes in developer mixed from the same concentrate. If I try this developer and paper combination again it will be for 7,8 or 9 minutes.

I expect that the uneven devlopment problem may have exacerbated the banding I was seeing.

 

[Ryuji]

Mattg,

First of all, congrats on eliminating the annoying pattern imprinting problem. That problem is very annoying so it's very nice to hear about one more success (I heard from many Nova users since I first posted on this issue).

The uneven problem is a bit of mystery, though I do know some developers are more prone to uneven development than others. Do you have a scan of such uneven prints? Do you get uneven prints by tray development? (A quick scan without any adjustment will suffice.)

 

[Bob F.]

Hi Bob, 21 degrees c, first immergence at about 45sec. 6minutes development almost as uneven as 3 minutes. I'm used to using an immergence factor as I have been using Gallerie until opting to give Warm Tone a try.

Previous to this testing I had made some good prints (apart from the pattern in the sky) that appeared to have lovely blacks, these were devloped for 3 minutes in developer mixed from the same concentrate. If I try this developer and paper combination again it will be for 7,8 or 9 minutes.

I expect that the uneven devlopment problem may have exacerbated the banding I was seeing.

Can't see any problem there as far as your technique goes (like I'm an expert! )... Very odd: rapidly running out of ideas!

Might be worth tying some freshly mixed developer from a new bottle as the stuff you have may have died (unlikely, but possibly worth a try: uneven development after 6 mins does sound like the developer may have gone to the big waste dump in the sky, or the paper has gone there first...).

Cheers, Bob.

 

[pentaxuser]

I once had a problem that was down to exhausted developer. Unfortunately it doesn't stop working completely. You get a print of sorts but it lacks "punch" and looks "veiled". I wasted a few prints before I took action.The key was noticing that when a different neg required a different grade, it didn't turn out that way. I coudn't alter contrast or remove the veiled effect.

Try printing at say 2 grades higher. If there is very little or no difference in the higher grade print then it suggests that the developer is exhausted.

The effect was not dissimilar to using out of date paper but from what you've said this is unlikely to be a cause unless your paper is very old. I was using Polymax which I got free with other items that I had bought from the seller who had had it for quite some time as he had stopped printing long before selling his darkroom items.

pentaxuser

pentaxuser

 

[Matthew Gorringe]

I haven't been able to get any sort of scans yet on my last tests, I have only been using a document centre for previous scans and it isn't able to show the flat greys as I can see them. I'll have to find someone to help me out with a proper flat bed scanner.

I'll also make some more tests tonight with Dektol that has been in the unit for a few days and then replenished, just to see what happens.

Just to restate that, even with the Dektol, the prints made in the Nova were more evenly developed than those I did with constant, but gentle, agitation in the tray.