Regarding development times

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Rho Sigma

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This question has been bothering me:

I develop in a small Paterson tank. From the moment I pour the chemicals, it takes a few seconds before they have all gone inside the tank. For 135 the difference is very little, but for 120 it can take about 10 seconds. Where do you start your timing, the moment you pour the chemical, or the moment it has all gotten inside the tank?
I'm guessing it shouldn't make an appreciable difference, but I'm still wondering what other people do.

Also, my searches didn't turn up anything, so apologies if the question has already been addressed.
 

Trask

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I pour, then start timing. As someone pointed out, the upper-most portion of the film strip (laying coiled on its side in the reel) will be the last to be be touch by developer when it is poured in. That that same portion will be covered longer by the developer as it is poured out. So in practice there’s no difference when you start timing, as long as you consistenlly do it the same. I start timing after pour in because I’m using two hands to pour, so can’t push the button on the timer until I can set the tank or beaker down.
 

Bill Burk

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Haaa I do it the other way around. I start time then pour. But you know... I think development doesn’t stop until I pour in the stop bath. And I don’t make allowance for that. I usually pour out just as the timer finishes.
 

Tim Stapp

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What ever method that you choose, just be consistant :smile:. That's what I've always been told!
 

Rudeofus

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Tetenals docs for their color chemistry state it succinctly: bath time is the time between the liquid touching the emulsion for the first time all the way to the next liquid touching the emulsion for the first time. This works at least for normal processing, i.e. if there are no long breaks between pouring out old liquid and pouring in next liquid. Note, that typical inversion tank process will get you slightly different bath immersion times for different areas on your film.

If process times are long enough, or if a bath runs to completion, it all doesn't matter much. That's one of the reasons why developer times should be >5 minutes.
 

Pentode

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+1

What you do is not as important as doing it the same way every time.

I start the timer after I pour in and I don’t pour out until the timer completes so, technically, my times are just a bit longer than I’m timing them for. I pour the stop bath as quickly as possible.
 

David Allen

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It actually does not matter which way you do the timing so long as you do it consistently the same very time. That way you will be able to adjust the time to get the correct development time for your working methods.

The sequence that I teach my students when processing their first roll of film is as follows (in this case Tri-X developed for 6 minutes at a dilution of 1:33 - as it is easier to measure than a strict Dilution B - in a Paterson tank suitable for one 120 film or two 35mm films):

First film development with Kodak HC110 1L Sirup:
Consistency (time, same agitation method, same thermometer, same measuring jugs, etc) and control of temperature are the keys to achieving reproducible negatives.

Prepare four one litre jugs. Mark one jug "Pre-wash", mark one jug 'Developer', mark one jug 'Stop bath' and mark one jug"Fixer".

Always use the same jugs for the same chemicals.

Fill a large bucket with plain water @ 20°C and use this for mixing all of the chemicals:
  • Pre-wash: plain water from bucket @ 20°C
  • Developer: 18mL HC110 syrup + 600mL plain water from bucket @ 20°C (suitable for one medium format or two 35mm films).
  • Stop bath: plain water @ 20°C
  • Fixer: 150mL ADOLUX ADOFIX express Fixer + 450mL plain water from bucket @ 20°C (suitable for four films when working to strict archival standards or for more when wishing to place economical use above all other factors).
  • Washing: plain water from bucket @ 20°C
  • Final rinse with wetting agent for a minimum of 2 minutes to a maximum of 10 minutes: 3mL ADOX ADOFLO wetting agent + 600mL plain water from bucket (x 2 jugs if processing two films). NOTE, if you live in an area with especially hard or mineral dense tap water replace the plain water from bucket with distilled water.
Pre-development sequence IN COMPLETE DARKNESS

Load the film(s) onto the spiral(s), place in to the tank, secure the light proof funnel lid and then the flexible top lid.

Development sequence with light on:
  • Pour the pre-wash into the developing tank, replace the flexible lid and start the clock.
  • You then start the clock at 00:00 and agitate the pre-wash constantly.
  • When the clock reaches 01:45 Pour the pre-wash out.
  • When the clock reaches 02:00 Pour the developer into the tank. First 30 seconds: Agitate the tank four times. Thereafter, agitate the tank once every 30 seconds. Agitation means gently inverting the tank so that the chemicals move to the top of the tank and then moving the tank back to an upright position. This should take approximately two seconds. After each agitation, you need to tap the bottom of the tank to ensure that any air bubbles are released so that the film is evenly developed.
  • When the clock reaches 07:45 Pour developer out of the tank.
  • When the clock reaches 08:00 Pour the stop bath in and agitate constantly.
  • When the clock reaches 08:45 Pour the stop out of the tank.
  • When the clock reaches 09:00 Pour the fixer into the tank.
  • Fix for manufacturer's recommended time.
  • Wash film using the Ilford wash method BUT make sure you thoroughly clean all parts of the tank (place film in a jug of plain water from bucket whilst doing this) before following this method.
Bests,

David.
www.dsallen.de
 

Sirius Glass

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Start timing at the beginning or end of the film, but be consistent on the fill and empty.
 

pentaxuser

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If consistency is that important and the lack of it amounts to about 10 seconds max then unless 10 seconds makes a real difference to the eventual negative, does it really matter? Unless the development time is very short and most times are not what is say the practical difference in say a negative developed for 10 mins and one developed 10 mins 10 seconds?

It may have been said by Roger Hicks only on his website and not here on Photrio so was never challenged but he mentions that if you decide to extend development from 12 mins then there is little point in extending the time unless it is more than 30 secs

So what is the minimum dev time where 10 secs makes a difference that can be seen in the negative that cannot be "corrected" in the print i.e. a noticeable difference that will show in the print which most people will recognise?

pentaxuser
 
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Rho Sigma

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what is the minimum dev time where 10 secs makes a difference

Yeah, particularly with C-41 dev, where 10 sec amounts to a substantial portion of the entire dev time. If I remember correctly, I've seen 15 seconds quoted as push time for C-41.
 

RalphLambrecht

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This question has been bothering me:

I develop in a small Paterson tank. From the moment I pour the chemicals, it takes a few seconds before they have all gone inside the tank. For 135 the difference is very little, but for 120 it can take about 10 seconds. Where do you start your timing, the moment you pour the chemical, or the moment it has all gotten inside the tank?
I'm guessing it shouldn't make an appreciable difference, but I'm still wondering what other people do.

Also, my searches didn't turn up anything, so apologies if the question has already been addressed.
from the moment it has all gotten into the tank until it is all empty again
 

Bill Burk

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from the moment it has all gotten into the tank until it is all empty again
That works too. I sometimes hesitate because the timer switch is near the ceiling. Do I start time and pour or pour then start time... I agitate for the first 30 seconds and then rap hard three times.... so I have to start the timer first (or lose track of 30 seconds).
 

Kawaiithulhu

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I'm definitely not a cork sniffing connoisseur of technique, but with the new (to me) Jobo here I religiously do the same thing every time: start the timer then pour + when timer ends then dump + start next time then pour + etc...
In this way no matter how many weeks it's been since my last roll the results will be the same because I've removed several variables from the process by following a simple and repeatable sequence.

And when you're dealing with irreplaceable negatives simple and repeatable is nice.
 

pentaxuser

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I accept that with C41 and 3 mins 15 secs, 10 secs might make a difference although my slowest filling and emptying tank is a Durst which might take 7-8 secs and my Jobo tanks for C41 are due to their design considerably quicker but with B&W development, times are a lot longer. Yes my "I wonder" statement fell on stony ground but I still seriously wonder if we are seeking spurious accuracy. A strict regime might make us feel better and I am not immune to this feeling but I do wonder if it makes a real difference.

pentaxuser
 

R.Gould

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I mainly use Paterson tanks, and I start timing when the developer is all in the tank, and start pouring out around 10 seconds before time up, so that it is empty when times up, it takes around 10 seconds with my oldest tank and perhaps 8 seconds with my newest, and slight differences in between, and with around 18 minutes in Rodinal 1/50 for my favorite film I can't see that 10 seconds will make any difference to the final negatives, I can see that for E6 or C41 films where developing times are much tighter that it could make a difference, but with black and white, where the developing times are longer, and the flms are a bit more tolerent, then ten seconds is nothinfg
Richard
 

Pentode

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I accept that with C41 and 3 mins 15 secs, 10 secs might make a difference although my slowest filling and emptying tank is a Durst which might take 7-8 secs and my Jobo tanks for C41 are due to their design considerably quicker but with B&W development, times are a lot longer. Yes my "I wonder" statement fell on stony ground but I still seriously wonder if we are seeking spurious accuracy. A strict regime might make us feel better and I am not immune to this feeling but I do wonder if it makes a real difference.

pentaxuser
Perhaps in that specific context it makes little difference, but Im a firm believer in sticking to a strict regimen because it not only eliminates variables that could hamper repeatability but it also establishes a sort of discipline that carries over to when we do need that kind of precision.

I’m intrinsically lazy. I’d rather not fuss over details. Sometimes we have to. Rather than trust myself to decide whether or not a specific situation requires precision and accuracy, it’s easier to just take that choice away from myself: ALL procedures in the darkroom require precision and accuracy. There; now I’ve left myself less room for error.
For me, it’s the only way I can get repeatable results.
 

MattKing

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With respect to developer, I'm a "fill the tank, start the timer, finish the time, dump the tank" sort of guy.
I might very well be a "start the timer, fill the tank, finish the time, dump the tank" sort of guy if I were to start c-41 or E6 processing.
 
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Rho Sigma

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Personally, what I've been doing is to start the timer, fill the tank, and add 8 sec to dev time to compensate for the time it took for the chemical to get in. But I cannot say I've been consistent. I've been rather cavalier with longer dev times.
 

Sirius Glass

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Start timing at the beginning or end of the film, but be consistent on the fill and empty.

from the moment it has all gotten into the tank until it is all empty again

Which ever one chooses just be consistent will all chemicals all the time. If one is consistent, then times can be adjusted if necessary.
 

Agulliver

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Use the same procedure consistently so that if you find you prefer different timings to the published ones, you can use your own.

But really...10 seconds here and there isn't very important. Most development times are 8-10 minutes....10 or even 20 seconds is not going to make much difference.

My own personal preference with a Jobo 1520 is to use an app on my phone which gives three beeps before the timer begins....I pour during those beeps. The pouring often continues a couple of seconds into the timed development. But it really won't make a difference to the negatives. Even on films which have development times more like 6 minutes, ten seconds represents 1.667% of the time.
 

pentaxuser

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I time development with an old darkroom alarm clock. It's a very good clock and one of my more essential pieces of equipment. It is divided into sections of 5 mins which are then subdivided into 4 sections of 15 secs. Am I out by a few seconds at the end of each time I develop?You betcha! Have I noticed the difference in my negatives? Well I can't say I have.

Would I feel better and more on top of my film development game if I was absolutely accurate? Quite likely, but I am having therapy to counteract it :D

pentaxuser
 

Bill Burk

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I'm definitely not a cork sniffing connoisseur of technique, but with the new (to me) Jobo here ....
Weren’t you putting together a WWII era darkroom? Haaa a Jobo must look conspicuously out of place...
 

Huub

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I am with Pentaxuser when it comes to developing B&W film: 10 sec doesn't matter that much.

Another factor to consider is temperature control. I do have some decent thermometers, but a good 0.1 c reading is hard enough for me. Half a degree more or less (the difference between 19.8 c and 20.2 c) would already amount to about 5% difference in development time, which translates to 30 sec with a development time of 10 min. Then there are these warm summer days when my darkroom is so warm that it gets problematic to keep the developer temperature constant during the 10 min it takes to develop the film. In all these cases i do compensate of course, but always with steps of 30 sec.

I also keep in mind that I want to develop my films to a certain contrast and that film shot in high contrast situation will be developed shorter then those in lower contrast. The difference between a N-1 development and an N development is about 30%:: 3 min in case of a development time of 10 min.

This is not saying that it is ok to use sloppy technique, but to be as consistent as it gets and to use some common sense when it comes to guestimating the right development time.
 
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