Truly, a geek!Prior to that I had decoded the Temp-Time formula from the Kodak Darkroom Dataguide wheel and ran the program on my 1984 Atari computer using a program I wrote in BASIC.
I agree with you on consistency. Even my fabulous Jobo, I don't really know what the exact temperature is in the drum. I use the Jobo lift, it's not temperature controlled. One thing that the Jobo has going for it is consistency. If the room temperature is consistent, and I follow the same pre-heat routine, I will have the same outcome.Thermometer accuracy aside, (consistency is equally important), there may be an issue with temperature drift over the development period if you don't have access to a tempering bath ala Jobo type devices.
See John Finch's Youtube channel, Pictorial Planet, for an interesting approach to adjusting development time to compensate for temperature drift. Basically the technique is to measure temp before development to establish base time. Then measure temp at the halfway point in development and see if there has been a change in temp. For each 1 degree C change adjust overall time by 10% to get new overall time. For example you start off with a calculated time of 10 minutes, at the 5 minute mark you temp has dropped by 1 degree C so your new overall time is 10 minutes plus 10% = 11 minutes. As you are now halfway through your development you split the difference in the time increase so your new total development time is 10.5 minutes. Similarly if your temp change is +1 C, (some developers produce an exothermic reaction), then your new total development time would be 9.5 minutes.
I normally keep solutions at room temp, (no tempering bath), and am developing at between 18 C and 24 C. I calculate my development times from the Ilford chart and seems to work well for the limited range of developers I use. No stand processing. I will be investigating and testing the above approach to handle temperature drift for the next film I process.
I tend to overdevelop black and white, it's a bit of a bad habit, carried over from my youth. It's easy to correct for when printing, it's not a best practice though. MHOFWIW.I'm nowadays suggesting everyone develop their negatives with 15% more time. Nothing is more sad than underdeveloped negatives. Overdeveloped negatives might be a bit denser but printable + on the safe side. And 15% is not even real over-development ..
Just curious.
As I mentioned in another thread, I recently discovered, quite accidentally, that my thermometer was one to two degrees off, which explained why I wasn't getting the negs I was expecting from past experience with the same film/developer combo.
So, replaced the dial thermometer with a digital cooking thermometer. So now, on the display, I have 1/10th of a degree Celcius, very precise, but, I'm starting to wonder, too precise?
Putting it another way. If I have a 10 minute development time for a chemistry at 20 degrees C, I know I must to about 9 minutes if my chemistry is at 21 degrees. Now what happens if my reading gives me 20,5 degrees? Do I keep 10, go to 9, or split in half and choose 9:30 as my development time?
I've actually answered my own question and decided to split the time in half in such a case, with anything under 0,4 being rounded downwards, and above 0,6 upwards. Don't think it makes that much of a difference, but I'm the type to like all his "i"s dotted and "t"s crossed and being a bit anal about it - at least as far as photography and the photographic process is concern.
So, out of curiosity, how many are on the psycho-rigid side of things concerning temperature, and how many have a life's-too-short attitude?
You only need to be within+/- 1degreeC for the developing temperature; everything else is obsession.
Agree here too.You only need to be within+/- 1degreeC for the developing temperature; everything else is obsession.
I tend to overdevelop black and white, it's a bit of a bad habit, carried over from my youth. It's easy to correct for when printing, it's not a best practice though. MHOFWIW.
I've actually answered my own question and decided to split the time in half in such a case, with anything under 0,4 being rounded downwards, and above 0,6 upwards. Don't think it makes that much of a difference, but I'm the type to like all his "i"s dotted and "t"s crossed and being a bit anal about it - at least as far as photography and the photographic process is concern.
So, out of curiosity, how many are on the psycho-rigid side of things concerning temperature, and how many have a life's-too-short attitude?
Looks like you are overstating temp bath. So long as every step is poured in at given temperature, it will continue to be stable enough. Only when room temperatures are vastly different from chemical temp will it matter to do it all in a bath. So it IS important to keep liquid temps quite close at every step (without trying to be SPOT on, but it's not hard to have it all within 0.5 C). Besides plastic tanks (Paterson, Jobo, and anything in between) are poor heat conductors. Temp inside does not change as much over processing time. And with pre-wet at given temperature it is all ready to go at start of actual processing.If you're developing without a tempering bath, or controlling ambient temperature, you are not even controlling the development process to within several degrees... My answer, is "close enough, no adjustment" because the adjustment is built into the process--times are given as minutes that represent ranges. Even with E6, I don't see differences until my process temp (which I would define as the average temp in the film tank during development, and don't get into whether this is a integrative number) is more than 5 degrees cool.
If you want to be "spot on" the process temp is what needs control, not the temperature only when you pour it in. That's the reason all the B&W charts are standardized at 68, standard lab room temp, so your tank temp won't wander enough to matter. 1/10 of a degree won't enter into the matter.
OTOH, I add a minute to all B&W times from the Massive Chart, because they always come out too thin otherwise. Optimized for scanning?
Probably demonstrates factors built into your workflow that you have self-adjusted for....
OTOH, I add a minute to all B&W times from the Massive Chart, because they always come out too thin otherwise. Optimized for scanning?
"Stable enough". My darkroom, today, is 66°F. In 15 minutes in a metal tank a 70° initial developer temperature will fall to very close to this temperature. If anyone is arguing that they need to pay 0.1°F (or, really, 1°) attention and is not measuring their end-of-run temps, they don't know what their temps are during the run. It's common with E6, which requires 106° for the recommended time/temp, to warm the chemicals to 108-110 for the anticipated fall to get an average during the run of 106°.Looks like you are overstating temp bath. So long as every step is poured in at given temperature, it will continue to be stable enough.
Probably to compensate for 66°! I don't bother to temper B&W. And I like more contrast.Probably demonstrates factors built into your workflow that you have self-adjusted for.
F or C, 5° is an order of magnitude more than 0.1° the discussion started with. That's how I can argue.And by "5 degrees cool" what is that? I have no idea what you mean by it, let alone F or C? By being this imprecise in response, how can you argue what matters?
"Stable enough". My darkroom, today, is 66°F. In 15 minutes in a metal tank a 70° initial developer temperature will fall to very close to this temperature. If anyone is arguing that they need to pay 0.1°F (or, really, 1°) attention and is not measuring their end-of-run temps, they don't know what their temps are during the run. It's common with E6, which requires 106° for the recommended time/temp, to warm the chemicals to 108-110 for the anticipated fall to get an average during the run of 106°.
I doubt many here are really watching their B&W temperatures very closely other than the initial temperature and have no idea what happens after that. Luckily, most people will have ambient temps close enough to intended chemical temps that it is "stable enough". Decades ago in newspaper and other working labs (EVERYTHING was Tri-X in D-76, of course) there was a posted time to use, the developer was in a 5-gallon tank with a spout at room temperature and the thermostat never changed, so it all came out OK. Mixing new chems, when needed, was done at the end of the day so the temp would stabilize overnight. Not very many people get that stability now.
Probably to compensate for 66°! I don't bother to temper B&W. And I like more contrast.
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