Low contrast negatives

[swmcl]

OK.

So. As we lower our concentration of developer chemicals we'll get more and more unreliable results. I'm sort of taking that as a given. Some of you may qualify this a little for me and tell me it is not so true for certain mixes and that some are better at being reliable and predictable at high dilutions.

I'm struggling here with my testing.

As I go to higher dilutions I'm trying to get a reliable low contrast negative. What I'm getting is a wobbly curve and the curve are not separating from one another as I would wish (the 5min and 6 min curves are too close to each other).

I'm also aware of the 'induction time' and that this will be affected by dilution also.

What is your experience ? Is a reliable low contrast negative possible ? (lets say lower than 0.5 or 0.48) Assuming a single process - not some split development or some such. Assuming the use of a Jobo tank in a rotary fashion.

It seems to me that FP4 in this case seems to not like really low gradients. I'm using Pyrocat HD at 4:4:300 in this set of results at 20 C and 6rpm in a Jobo 3006.

The results show nothing happening and them BAM! it takes off at a crazy rate of knots (for the dilution).

I should mention that I have some really nice predictable results at 5:5:300 and 6:6:300. 5mins at 5:5:300 is giving me 0.48 but it is too short to be reliable so I'm chasing low gradients and want the developing time to be lowish. I'm also wanting the strength of the developer to be strong enough to develop a really long SBR. I am cautious about a weak solution ever being able to develop stronger highlights. I'd rather have a stronger solution for a shorter time.

I'd be happy knowing I could have a straight line and reliable development of say 0.43 for say 7min.

I'll try to attach a simple pdf. The graph is on the second page.

Cheers,

Steve

 

[gone]

You are way beyond me on this post, but I do know that if you shoot w/ a low contrast lens you get low contrast shots (all things being relatively the same). That would appear to be the simplest way to go.

 

[Jim Noel]

I believe you need to try other developers which by formulation are low contrast developers. Some of these are D-23, LC-1 and LC-2 , and there are many others.
Also, my experience is that rotary with the same developer will produce more contrast than will tray development, semi-stand development or stand development.

 

[Doremus Scudder]

I second the idea to use a Metol-only developer like D-23 as well as to switch from rotary to another kind of agitation. Diluting the developer a lot will have a couple of results. First, you could exhaust the developer, with which the shadows and mids develop with separation, but before the highlights can be fully developed, exhaustion occurs. This results in a curve with a marked lower-density shoulder (a useful tool in some applications). If you have enough developing agent, and a high enough dilution, you should, theoretically at least, be able to reduce contrast by reducing developing time. However, this can result in a shouldered curve as well. A softer working developer like Metol might give you a straighter gradient and still have a workable developing time. BTW, I developed film in HC-110 at five minute times for years and never had a problem with that being too short (no unevenness). You might want to rethink your desired time.

Best,

Doremus

 

[cliveh]

You have far too many variables to ever get consistent results. Simplify your process.

 

[swmcl]

Cheers guys,

I know I am bordering on the limits with a low time. I do appreciate the comments about the setup but I do not have a choice with regards development routine. I simply cannot use stand development there is no equipment to stand-develop 5x7 film in daylight ( I do not have a darkroom). I am using a slow rotation to avoid excessive oxidation and am above the minimum amount recommended by Jobo for the tank I'm using (300ml - 210ml)

Clive, perhaps I have not explained things well but I am very much in control of variables. Perhaps you could be more specific with your comment ?

I am also seeing the same erratic behaviour with another developer at the low times. Predictability and reliability comes with concentration of chemicals.

So given the circumstances, (I'm using a long shelf life Pyrocat-HD in a rotary setup) what is the alternative ? A Metol-based catechol developer ? I wouldn't know a name of one. Any suggestions ?

Cheers,

Steve

 

[cliveh]

Clive, perhaps I have not explained things well but I am very much in control of variables.

Are you sure about that?

 

[Jim Noel]

One point which you may be overlooking is that the quantity of developer is what is important. If it is diluted, then a larger quantity of the diluted product is necessary.
For instance using HC 110 at a dilution of 1+7 from syrup may give me a development time of 5 minutes, and require one liter of the diluted developer to fully develop the batch of film.
If I use a dilution of 1+ 70 from syrup, which I often do, the total quantity of developing solution needed grows from 1 liter to 10 liters to provide sufficient developing agent. If I use only five liters of this very dilute solution, the active developer will be exhausted before the required time is up and will give weak negatives and irregular results.

 

[ic-racer]

I processed some high-contrast recording film to continuous tone by using 16 degrees centgrade and 4min development.
(there was a url link here which no longer exists)

 

[swmcl]

OK. On Doremus advice I have mixed a Pyrocat MC developer this morning. Yes it isn't a 'metol only' developer. Here are two sheets ...

As you'll see the low-end response is better but the gradient is only slightly lower at 5mins than at 7mins. I do observe that it doesn't 'take off' like the Pyrocat-HD. The mix was 4:4:300 just like the Pyrocat-HD. So that is 4ml Part A : 4ml Part B : 300ml distilled water. I use a 4min pre-soak in distilled at all times for everything.

I'm trying to get a reliable method of getting flattish negs so that I have a high SBR capability on optical printing. I do realise that I may not achieve this but I would've thought many of you may have come across this before. If I can't do it then I guess those shots will need to be digitally printed.

The MC does seem a bit more reliable down low than HD. I have a very good respect for the HD. It is reliable.

 

[swmcl]

ic,

Thanks for the link. You've been down this road more than I wish to so I'll add a few of my thoughts.

I believe the drop in temp will be very helpful in the cause but ... I process outside on the back porch area. In an Australian summer it may be a little hard to achieve 16 C !! I have a large custom built aluminium tank into which I place around 45 litres of water which is passed through a 3000 litres/hr aquarium pump and then a 1k5W aquarium cooler/heater. I roll the drum by hand on a roller beneath the water surface. The cooler has made my life very much better and I could dial in 16 C on it and it would achieve the goal but it is not accurate and has about 2 degrees hysteresis. The main problem is that the 16 C will drift very quickly.

I have not had reliable results from Rodinal in a constant agitation environment. Although it was only a couple of months ago I do not wish to go back to it. I am happy with the Pyrocat and was hoping to use it because I have lots of it and it is long lasting. I believe Rodinal is best suited to a stand, semi-stand, tray or tank situation which is impossible for 4x5 and 5x7 sheets without a darkroom AFAIK.

The 7min curve with 4:4:300 PyroMC will give 10 stops on the scanner so I guess that'll have to be it ! I can tone it down to say 5min 30sec but as you can see the ISO is dropping substantially - something like 25 on the 5 min result (FP4).

Cheers,

Steve

 

[Doremus Scudder]

Steve,

Are you simply trying to find extreme contractions for optical printing high SBR subjects? I.e., what we Zonies would call N- developments? If so, may I suggest that you include the printing process in your testing. The film curve needed to reproduce well at contractions is often not a straight line. A definite shoulder (i.e., compensated highlights) is often desirable.

And, to expand your information base, you can do a lot of searching on what people do for N-3 or N-4 developments. For me, I've refined a SLIMT procedure in which the negative is pre-treated in a weak potassium ferricyanide solution before processing. I have worked out, through testing and trial and error, schemes down through N-4 that don't rely on greatly reduced development times or weak dilutions. Check out David Kachel's site and the pages on the "New Sterry Method" and "SLIMT." I find this method works very well (although I rarely contract more than N-2).

Another thing to note is that most good printers, when working with contraction negs, prefer to work with a too-contrasty negative and then use print manipulations to bring it under control. A straight print from a contraction negative in which the overall negative contrast matches the paper contrast often (mostly, for me) appears too flat. I like to dodge and burn plus pre-flash for those negs with really dense highlights.

In short, simply matching contrast ranges will not necessarily get you a good print. Try a test subject and then print it to see where you stand. Personally, I tailor my contraction negs to print on grade 3 paper (the curves seem to fit better) and like a neg that's about one Zone number too contrasty, which I deal with using manipulations and sometimes a softer working developer. It's all about local contrast and separation, not necessarily "fitting" the negative contrast to the paper.

Best,

Doremus

 

[swmcl]

Cheers Doremus,

I am living in a rental at present and cant make a darkroom. I have purchased and been gifted a number of enlargers and I have been collecting various bits and pieces in preparation. For now, I am simply trying to get my procedures sorted to stop getting thin negs ! I do prefer the stronger gradients but am still trying to get a set of low-gradient curves to fill out the Expodev possibilities I guess.

I feel so much more confident having done the tests. Everything I've done up to this point seems so chancy. In looking back at the data the Pyrocat MC curves actually do the same thing as the Pyrocat HD ones in that the curve for the shorter time takes longer to 'take off' but when it does it has a steeper gradient than does the curve for the longer time. So the behaviour is looking to be something that happens commonly. Simply I gotta keep away from those times ! The negs will look weird.

I downloaded the Kachel pages the other day actually but if I can't get it sorted in a simple way I'll go digital.

Thanks for your encouragement.

Steve

 

[Bill Burk]

... For now, I am simply trying to get my procedures sorted to stop getting thin negs ! I do prefer the stronger gradients but am still trying to get a set of low-gradient curves to fill out the Expodev possibilities I guess.

Well, sounds like you have a good plan (to fill out the ExpoDev possibilities), but not necessarily to stop getting thin negs. I have a similar goal, but I focus on avoiding thin negs.

On a recent curve family I did for TMAX 100, I used D-76 full strength to achieve high contrast possibilities up to 1.2 Contrast Index (CI), and D-76 1:1 to achieve about 0.40 to 0.70 CI

I haven't "filled out" the possibilities beneath 0.40 CI because I don't have a pressing need. If I did want lower CI, I'm thinking I would look into a Metol-only developer (Kodak D-20) or a POTA developer, because I don't like development times shorter than 5 minutes either.

Now switching developer to D-20 or POTA will reduce the effective film speed. Really. So I'd test for exposure index. Otherwise, if I were sticking with D-76 I'd just figure Delta-X justifies not changing the film speed all around with changes in development time.

I think 0.50 is a very useful gradient, especially if you use multigrade paper. Since you barely get down to 0.50 with your current arrangement, I understand why you would want the possibility to go lower. To fill in the possibilities as you say. I'd want to have a process that didn't back me up against a wall.

 

[swmcl]

Blimey Bill !

A CI of 1.2 ? What kind of density does that ? Hmmm. My best with my own brew is 0.96 and that goes through to 2.85 density in 10 mins ..

Mine was a mistake - not a deliberate thing.

Fun all the same.

 

[JPJackson]

This test was made with film developed in open tubes and trays as per Sandy King and David Kachel (late 80's article). I develop all my 5x7 sheet film in this manner. There are lower contrast possibilities ( less than .43) at shorter times. I usually develop for G=.5 or .47 for contact printing on MGFB classic.

 

[RobC]

to OP...

I don't know exactly how you produced those wavy curves but I'll assume it was by photographing an even toned subject.
Two factors which will give you wavy curves are changing lighting such as clouds passing by and also if you have shutter or apertures which aren't quite right. Apertures are set by mechanicals and depending on exactly how, they will sometimes not fully open up or close down. Its usually best to always close down to them rather than open up but you may need to also test the other way to see which gives you best result.
Then you have shutter speeds which are sometimes off. If you have set a shutter speed and then adjust aperture for a few shots you may get part slope based on a slow or fast shutter speed and then you change shutter speed and and use another set of apertures and get a different slope because that shutter speed is correct, fast or slow.

The whole point being your assumption its the development putting the waves in your test could be wrong and I strongly suspect its the shutter or aperture which is doing it.

So you need to first prove its not the shutter or aperture by doing some tests where shutter speed remains constant and adjust by aperture only and then another test where aperture remains constant and adjust by shutter speed only. If either of those curves are wavy you'll know which is causing the problem. Obviously lighting needs to be constant and target a normal CI for the tests using a known good devloper like D76.
And check light reading between each exposure to be sure it hasn't changed. A digital meter with .1 or smaller increments is best for this.

Only when you have done that can you start pointing the finger at the developer.

I am assuming that because you are targetting a low CI you are testing for a long SBR and with a long SBR you will run out of apertures you can use for the test so will have needed to change shutter speed or aperture as part of the test. i.e. one or both will have been changing.

 

[Bill Burk]

Blimey Bill !

A CI of 1.2 ? What kind of density does that ? Hmmm. My best with my own brew is 0.96 and that goes through to 2.85 density in 10 mins ..

Mine was a mistake - not a deliberate thing.

Fun all the same.

When you want to play with William Mortensen's lighting ratios, you need high contrast developing! So it opens the door to new ways of thinking that you can light your subject with a 1:2 ratio and develop to gamma infinity.