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Measuring time between agitation


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Hello,

 

I want to make sure that agitation intervals during film processing

are consitent. It happens to me to forget agitations, especially when

development times are long.

 

The timer gives me only a signal when time is over. I was thinking

about a kind of metronome, that could give me acutstic feedback once

a minute/30seconds... Normal metronomes have about 30 bpm as minimum

frequency, whereas I would need 1 bpm!

 

Are there such devices?

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Dear Thomas,

 

Try a cheap cassette recorder with the times recorded on it. I have used this system for years. It is excellent, even when you are working in total darkness.

 

Be wary of anyone who tells you always to under-develop compared with the manufacturers' times, incidentally. What works for them will not necessarily work for you. I very seldom develop for less than the recommended times. This is unusual -- more people find that curtailed development suits them better -- but it is far from unique.

 

The manufacturer's times are almost invariably the best starting point. Why would they deliberately recommend anything that wasn't? And they are always careful to point out that these are STARTING POINTS.

 

Cheers,

 

Roger

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Roger Hicks hat geschrieben:

 

"The manufacturer's times are almost invariably the best starting point. Why would they deliberately recommend anything that wasn't? And they are always careful to point out that these are STARTING POINTS."

 

1. As reported in Anchell and Troop's Film Developing Cookbook, Bob Schwalberg had a 30-year-long dispute with Kodak over developing times. This discussion is a side-bar on page 93. Schwalberg recommended significantly less development than Kodak for Tri-X and D-76. Some of this may simply be carelessness.

 

2. There are numerous reasons why a firm might want to provide generous times. One is the belief, the mistaken belief, that modest over-development is better than modest under-development in cases of error on the part of the user. It also guards against developer weaked by age in storage before use as well as by oxidation and use after mixing. Developers are usually made 10% stronger than specified to withstand store-shelf deterioration. Together these factors can lead to signifant a degree of over-development if one is using fresh product.

 

3. Personal observation has shown that developing times are usually excessive in products that I have used, with few exceptions, on my own film, and with films that I have seen processed by others over the years.

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Dear Hans,

 

Your personal observation shows you one thing. Mine shows another. The main point I wished to make is that for some people, developing to a higher gamma is better; for others, lower.

 

Many novices believe that if they depart from the manufacturer's recommended times, they are doing something wrong. Then they are faced with the common advice from 'experts' that they should always develop for less time. If they don't follow that, they feel doubly wrong. A lot of Zone System advice can be summed up as 'overexpose and underdevelop', and if that works for you, fine. But it won't work for everyone.

 

I normally use the ISO speed or something very close to it -- though admittedly only when I meter properly, by reading the shadows with a spot meter for exposure and highlights for brightness range (development) -- and most of the time I develop for about 10 per cent longer than the manufacturer's minimum recommended time. It works for me. I do not presume to tell the rest of the world that it is the only route.

 

'Mistaken' belief? I wouldn't say so. Nor would the manufacturers. Another example of your presenting your opinions as fact.

 

Cheers,

 

Roger

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It should be pointed out that Barry Thornton in the book 'Edge of Darkness' argues that developing times supplied by manufacturers are often cut to one's advantage and provides convincing illustrations thereof. So, I have cited two experts who offer this advice (Schwalburg and Thornton). There are others.....
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Dear Hans,

 

Ten opinions -- no matter who the 'experts' are -- don't make a fact. I speak as onne who is sometimes called an 'expert'.

 

Ilford's development recommendations give close to ISO speed and contrast. If you don't want ISO speed and contrast, feel free to change your EI and development time. They say that; I say that. My only argument -- with your opinion and that of others -- is that you always need to over-expose and under-develop. Many do. Some don't. All I want to say is that no-one should swallow what the 'experts' say blindly.

 

As for the over-strength developers, words fail me.

 

Cheers,

 

Roger

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The following question has been forwarded to Eastman:

 

Dear Sirs:

 

1. I have read or heard in various sources that it is common practice to prepare developers at an extra-strength state to withstand shelf storage for extended period, so that 'normal' strength will be attained after a given period.

 

Can you enlighten me on this matter?

 

2. No doubt Kodak has been asked this one before: the 'silver content' of various films and papers is supposed to have been diminished by deliberate acts of Kodak to achieve greater profitability. Specifically, some have reported that films such as Tri-X have been changed to contain less silver. I would like Kodak to comment on this.

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Dear Hans,

 

I don't know what Kodak would say, but I do know what Ilford would say, because I have asked them. They were as amused as I by these fantasies. I'd put more faith in them than in Anchell and Troop. I could check with other developer manufacturers, but there hardly seems much point. Next time I'm talking to Geoffrey Crawley I'll see what he says; also Roger Parry at Paterson and John Herlinger at Fotospeed.

 

Putting more of anything into anything (silver into film, phenidone into developer) costs money. You therefore use the minimum you need to get the optimum results. The accountants who run the companies will allow nothing else.

 

The R+D of making 'new technology' films, and the cost of running two lines side by side (old & new) outweighs any savings on silver.

 

The reason words fail me on developer strengths is that you immediately run into the philosophical question of what 'specified' means. If they are made up 10 per cent strong, that becomes the new specification...

 

I am in touch on a fairly regular basis with quite a number of people in the industry who actually know what they are talking about. Even after aiming off for commercial secretiveness, I don't think I get too many lies.

 

Cheers,

 

Roger

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"The reason words fail me on developer strengths is that you immediately run into the philosophical question of what 'specified' means. If they are made up 10 per cent strong, that becomes the new specification..."

 

Well, the developer D-76 is published. If we mix up the formula and compare its activity to one mixed from a fresh package, we could see if there is any difference, no?

 

It is not unusual for products to be designed to age on the shelf before sale. Amateur photographic film is a perfect example. I feel sure it is not an isolated example.

 

Given the normal shipping, inventory/storage, and store-shelf time, there could be a substantial interval before anyone makes use of the product.

 

Developers deteriorate over time.

 

The 'aim point' for liquid Microdol-X activity, for example, could well be 9 months after manufacture, not 1 day.

 

Hans Beckert

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  • 1 month later...
I find something like a Gralab 300 is ideal for film- just watch the hand and agitate on the minute. The only time I miss an agitation cycle is if I'm doing something else instead of watching the clock. It wouldn't be hard to make an electronic timing circuit that would sound a short beep on the minute. I don't know of any commercial item like that, but there may well have been one. Tons of timer projects have been published in the electronic mags over the years, and there have been various feature laden timers offered commercially. If you keep a PC in the darkroom, use one of the shareware programs or write something in BASIC!
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I use an HP programmable calculator (48GX) and wrote a timer program for myself. <p>

It's very easy. You can have different tones of beeps. I also have it beep the agitation cycles and the finishing tones beginning 10 seconds before the time is up. I never need to even look at the thing, just go about doing other stuff and listen to the programmed tones. You can have different "programs" for different film/developer/fix combos. For example, you could have 1+300 Rodinal development with only one agitation cycle for 20 minutes or something, and more normal cycles for others.<p>

Lesser calculators may do nicely too.

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