Development time vs. developer concentration

Hey folks,

I've been developing my negatives with HC110 (diluted 1:50) for a few months now. I was following Jason Brunner's recipe for the HC110 and so far, the results are coming out great! The development times aren't long, but I was wondering what the benefits of using a more dilute developer were. Does it produce smoother tones? Does it make the negatives more contrasty? Or even less?

Hypothetically speaking, if one were to use a more concentrated developer solution and calculates that the development time is 5 minutes, and later dilutes that solution and calculates a development time for 10 minutes, would the results be any different?

Thanks,

Jason

jasonjoo said:

Hey folks,

I've been developing my negatives with HC110 (diluted 1:50) for a few months now. I was following Jason Brunner's recipe for the HC110 and so far, the results are coming out great! The development times aren't long, but I was wondering what the benefits of using a more dilute developer were. Does it produce smoother tones? Does it make the negatives more contrasty? Or even less?

Hypothetically speaking, if one were to use a more concentrated developer solution and calculates that the development time is 5 minutes, and later dilutes that solution and calculates a development time for 10 minutes, would the results be any different?

Thanks,

Jason

Click to expand...

Jason, sounds to me like you need to establish some measurable (difference) criteria and perform some carefully controlled testing.

I started out with HC-110 at 1:31 (dil. B). Once I read the Neg and saw other dilutions mentioned, I decided to try a higher dilution, and now 1:63 (known as dilution H) it is almost all I use. Recently, I switched to Ilford's HC as well and retested two of the films I knew on HC-110. The results are nearly identical; same film speeds and within 30 secs on times.

The main (and measurable) difference for me going from B to H was increased film speed (based on calling .10 above FB+F zone I). FP4 was a 125 film for me at dil. B, and a 200 film in the same camera and same agitation at dilution H. It also seems to cause sharper grain and more contrasty shadows. The highlights never get unprintable at this dilution, barring a huge exposure error.

Development times are long (about twice dilution H), making minor inconsistencies batch to batch have less impact. I process at 75F to shorten the time, though. I agitate continuously for two minutes, then once every minute for two minutes, then once every two minutes for the remainder when doing normal or minus development. When I want + development, I keep it at one minute intervals.

When the developer is diluted this much, and it is standing there developing between agitations, the developer covering the highlight areas has its activity used up fairly quickly, while the less exposed areas take longer to exhaust the developer. Thus, the shadows get a wee boost while the highlights are creeping along. This is especially true when you don't agitate that much. D-76 at 3:1 is similar. This is the layperson's (AKA my) way of explaining it. Others here will explain it in more detail and more accurately, but that is the gist of it.

Tom, I guess it is best to do testing on my own. I am a very simple person and am not one to experiment, but maybe this will be the best for the long run.

2F/2F, thanks! I am a layperson myself Keeping things simple is the way for me. I tried reading a copy of the Negative by Ansel Adams, but it reminded me too much of chemistry class. I'll take another look at it this week.

Jason

jasonjoo said:

Tom, I guess it is best to do testing on my own. I am a very simple person and am not one to experiment, but maybe this will be the best for the long run.

2F/2F, thanks! I am a layperson myself Keeping things simple is the way for me. I tried reading a copy of the Negative by Ansel Adams, but it reminded me too much of chemistry class. I'll take another look at it this week.

Jason

Click to expand...

Yes Jason IMHO, you need to determine for yourself what developer/film combination gives you the result that best suits your artistic vision.

[QUOTEYes Jason IMHO, you need to determine for yourself what developer/film combination gives you the result that best suits your artistic vision.[/QUOTE]


Jason,
Tom is right.

Increasing the dilution has only one effect, that is to increase the time it takes to develop film.
If you maintain the same proportion of agitation to development time, the results will be the same.
If you reduce the concentration TOO far, the developer will exhaust before the film is correctly developed.
With HC-110, that might not be until 1+200 or so.

Different films respond differently to dilution. Some are linear, some are curves; departing from Kodak's data, you will have to work it out for yourself. It isn't hard.

I use HC110 and I keep Dil 'B' in a working solution. If I need to further dilute it I always can but why keep a week solution when you can weaken a stronger one as needed. As a matter of fact I'm gonna be playing with that when I get my Fomopan 100 4x5's.

You can use whatever dilution you would like as long as you 1. have a certain amount of syrup/stock per roll, and 2. have enough working solution to cover the film. With HC, it is recommended to dilute in a manner that will keep at least 3 mL of syrup in the solution per roll of 35mm/120. This means 0.75 mL per sheet of 4x5. With D-76, I think the min. is 2 oz. of stock in the solution per roll, which means 1/2 oz. per sheet of 4x5, but double check me on that one, as I think 1 oz. might still work.

So, say you need 3 mL of syrup to do one roll, and you need 250 mL of working solution to cover a roll completely. Divide the little one into the big one and you get your max. dilution that will develop the roll. It goes 83-1/3 times. So you can use it up to a 1:82 dilution. (1:79 is the easily measurable dilution that is closest.)

Which if developing two rolls would be around 1:39. At that ratio I would put processing time at about eight minutes.

Number of rolls would not change max. dilution, because you would need to double both the amount of syrup and the amount of working solution. For two rolls, you would need 500 mL of working solution to cover the film, 6 mL of which would have to be syrup. The ratio ends up the same because you doubled both parameters. And you can't guess a developer time without knowing what film it is and what temperature.

If you were talking about using a small amount working solution to process sheet film in a Jobo expert drum, it does not have to cover the film, so in this case the max. dilution would have to be lower. For ten sheets you need 7.5 mL of syrup, and between 210 and 350 mL of solution in a 3010 drum. You could use anywhere from 1:27 to 1:46, respectively. Using 250 oz., like I always do in this tank, max. dilution is 1:32, so I would just use dilution B (1:31). Then again, I never have ten sheets b/w of 4x5 that need to be processed the same way, so I just use the Jobo for color. Nonetheless, the theory still applies.

Thanks everyone for your help.

2F/2F, you mentioned everything I needed to hear!

Jason

Just one caution:

Don't do what I just did - confuse 1 - 7, with 1 - 6 (don't ask).

Grade 1 - 1.5, here I come .

Matt

Christopher Walrath said:

I use HC110 and I keep Dil 'B' in a working solution. If I need to further dilute it I always can but why keep a week solution when you can weaken a stronger one as needed. As a matter of fact I'm gonna be playing with that when I get my Fomopan 100 4x5's.

Click to expand...

I don't use a working solution at all. I just use a syringe to take the correct number of ml from the bottle direct to the water for the final solution. The syringes are often available just by asking the druggist, but they have them for sale as well. I believe their primary purpose is to feed medicine to babies.

Indeed, Matt. You have to be careful about how you state it. A 1:7 ratio is actually 1/8th stock. 1:31 ratio is 1/32nd stock. 1:63 ratio is 1/64th stock. It won't *that* make much of a practical difference, but you will be having a fun time measuring out 1/7 of a batch as opposed to 1/8.

Also, Don is correct that if you maintain a constant ratio of agitation to amount of stock used, you should get the same results at any dilution. However, getting the same exact results would defeat *some* the purpose of using a high dilution (film speed increase, more contrasty shadow detail, keeping the highlights in check). Therefore I do not keep the ratio the same, but switch to infrequent agitation in the last half of the development.

The point about dilution NOT being the cause of contrast control, etc., is important.

Too much time has been spent huddled over a Jobo,
spinning film all night at different dilutions, waiting for the magic to happen.

Unless agitation is reduced, no magic. So, dilution is important, but not the cause.