Room temperature ? (Not temperature of chemicals).

[mal_thomas]

Hello,

I understand the chemicals need to be at 20C (68F). I always ensure all my solutions are at this temp..no drama there.

 

Now on cooler days it is easy to maintain my ambient room temperature at very close to the same temps.

 

However it is mid summer now (temps around 38C-40C+) and, even with the whole house AC on, it is very difficult and expensive to get

the room down to anywhere near those temps.

 

So, my question is, whilst I always use my chems at 20C(68F), how critical is the ambient room temp? I can easily get my developing

room down to 24C(75F) on most really hot days. Is this ok, or do I need to wait for cooler days to develop my films?

 

Cheers

Mal,

Oz.

 

(Ilford films, 35mm and 120, Ilford chems, Rondinax 35U and 60 daylight tanks)

[Sandy Vongries]

<p>There is a relationship between developing time and temperature. Cooler (reasonably) equals longer processing, warmer equals shorter. I have been in your situation (with Kodak chemistry) , and it can work. You can also use water baths for your developing canister. Check with Ilford, info is likely available. Cheers.</p>

[steven_clark]

<p>Air has almost no heat capacity, while water has one of the highest heat capacities by weight you can find. The short of it is your air temperature has probably nearly no effect if you can keep your chemical temps in line.</p>

[mal_thomas]

<p>Thanks Sandy,<br>

Am able to easily manage the temp of the chems, as you say, add cold/warm water baths as required. <br>

But do you think if the room itself is a bit warmer it will have any detrimental effect ? I can experiment of course, but I have a roll of 120 I am keen to develop from a recent trip, so I don't want to spoil it. would rather wait till the weather cools :-)<br>

Cheers<br>

Mal<br>

Oz</p>

[Sandy Vongries]

<p>Suggest a dry run -- bad film or no film with water, monitor your tank temps every couple of minutes through the process. Then you'll know. B&W is pretty tolerant, color not so much.</p>

[maris_rusis]

<p>No! Chemicals don't have to be at 20 Celcius. I reckon this temperature is a historic accident left over from the early days of photographic research when Northern Temperate Zone tap water would conveniently run at 20C or thereabouts. Higher temperatures mean shorter processing times which is a huge convenience if you have a lot of film to do.<br>

<br />My darkroom airconditioner is set at 24C and my preferred black&white processing temperature is 30 Celcius. Typically a sheet of film that takes 11 minutes to do at 20C takes 4 minutes at 30C. That's a big reduction in dark time if there are dozens of sheets to do. And the higher temperature does not hurt film at all. And the short time does not cause non-uniform processing if you work smoothly.<br>

There are time versus temperature charts which enable you to adjust development time for whichever temperature is most convenient. This approach actually enables increased precision because temperature is technically hard to adjust and stabilise but development time is trivially easy to measure and repeat to the second.</p>

 

[aplumpton]

<p>What Steven said (and Sandy in his first posting and also Marius). 20 C (or 68 F) are just normal ambient temperatures in some places, so that was chosen by the manufacturers for base line times and temperatures. But you can vary the temperature as long as you keep it relatively constant during the processing and for those relatively short times the air temperature, as Steven said, will have little or no effect. Ilford (and others) publish with their chemical fact sheets a graph of temperature versus time. The only problem going to higher temperatures with some brands of roll films (35mm, 120), daylight developing tanks (pouring in, pouring out times being important) and available developing agents is that the effective time of development becomes too short (of the order of 5 minutes or less) to accurately measure and reproduce when higher temperatures are used. You can dilute many developers to extend the time, but that can also produce different grain, contrast and resolution in some cases, that may or may not be desired. </p>

[mal_thomas]

<p>Thanks for that chaps, some new ideas/options to ponder. Appreciated.</p>

<p>Cheers<br>

Mal<br>

Oz</p>

[thirteenthumbs]

<p>Developing times of less than 5 minutes are not recommended due to risk of uneven development. Maris is lucky if he has good development at 4 minutes and is probably very experienced in his work flow.<br>

I have processed color C41 @103°F/39.4°C in a 58°F/14.4°F room on a tile counter top using a 110°F/43.3°C tempering bath and had less than 1°F temperature change throughout the processing session. A pan or sink at the desired temperature as the chemicals + a little ice can keep 68°F-70°F tempering bath stable in a 75°F-80°F room easily. The tempering bath should cover half the storage bottle. Most developers have times for 65°F to 75°F.</p>

<p>Fill the developing tank with water the desired working temperature and monitor how long it takes it to change 1°F/.5°C if using 68°F/20°C. Now time again in a tempering bath. Other chemicals and wash water can shift 3°F/1.5°C without ill effects.</p>

[bruce_watson1]

<p><em>No! Chemicals don't have to be at 20 Celcius.</em></p>

<p>Not exactly. It depends on the developer. Developers that contain hydroquinone will give different results depending on developer temperature. This is because the hydroquinone is more active at lower temperatures. This can be used as a tool.</p>

<p>For example, a metol/hydroquinone developer like D-76. If you lower the developer temperature, developer action is more hydroquinone and less metol. If you raise the temperature, the opposite happens. So, if you have film that needs some contrast boost, you lower your developer temperature (and of course compensate development time properly). If you want a somewhat softer image, you raise the temperature.</p>

<p>When in doubt, 20C is your friend.</p>

<p>As to the air temperature. Higher air temperature will of course eventually raise the temperature of your developer solution until air temp = developer temp. The question is, how long will this take? You can actually work this out mathematically, but it's hardly worth it. It's largely a function of the temperature differential. And you can control the equalization process easily enough with a tempering bath and some ice cubes.</p>

<p>For example, I found that the ice from my main freezer is the right size and temperature to lower the temperature in my Jobo's tempering bath by 0.1C / cube. If I measure it at 21C, ten cubes brings it down to 20C like clock work. If you have ice available, air temperature becomes nearly completely moot.</p>

[Bill Bowes]

<p>Hello everyone. Put all the above advise to work in one, simple step. Use an Igloo cooler to hold enough chemicals and water (rinses) and keep them at whatever temperature you choose for developing by adding cool / warm water. Using Nikor 450ml tanks, this set up has enough liquid for two 35mm or one 120 roll, and using the Ilford method of rinsing, you will have archival negatives. Bottles are re-cycled beverage types. 970ml for the big ones, 570 for the two green ones (developer and fixer). If you are not the Martha Stewart type (that's me!), the Igloo also keeps the "clutter" down. Enjoy, Bill</p><div></div>

[craig_shearman1]

<p>I've developed film for 40 years and I've almost always done by B&W at 75F. I get cold easily, so that's the temperature I keep my house at, and it conveniently means that all my chemicals are always ready to go with no need to warm them up or cool them down. A huge convenience when you're in a hurry.<br /><br />Yes, development times less than five minutes can, at least in theory, make it more difficult to get even development. But Tri-X in D-76 is about five and a half minutes, so that's not a problem. And C-41 is about 3:15 (at 102 or is it 103) and that works just fine.<br /><br />When I worked for newspapers, we never went any cooler than 75 because we were always on deadline -- the temperature gave us a quick developing time and mean we didn't need to lose time getting the developer to the right temperature.<br /><br />Kodak's development charts show times for temps anywhere from 65-75.<br /><br />As for temperature affecting contrat, I prefer to start with a "standard" negative and adjust contrast in printing. In 35mm or medium format, it's seldom that every shot on a roll would need the same adjustment, so that rules out changes in development most of the time, at least in my experience. If it works for others, I have no argument against it, just saying it's not something I have found necessary.</p>

[david_l3]

<p>I used to live where my darkroom was 57-59F all year. Now it's 77-78F in the summer, and tap water is >80F. Here's a trick to enlighten oneself. Measure your developer temperature before you pour it into the tank, then when done, pour it into a plastic bucket, and immediately measure the temperature again. If ambient temperature is much different from your processing temperature you will get a shift. I finally realized it's the weight of the tank/drum, and the contents (reels, film, etc) that are room temperature before you start. The mass of the drum/tank hardware heats, or cools, the developer, sometimes significantly. I have seen 5 degrees difference. If you know the difference between the entry and exit temperature of the developer, you can make slight adjustments to temperature or time. Take notes and faithfully repeat the details that resulted in successful negatives. </p>

[glen_h]

<p>The heat capacity of water is much higher than air, so it will warm up fairly slowly.</p>

<p>If it is in an open container, water solutions will cool much faster from evaporative cooling, like soup in a wide bowl. So, it is easier to keep them cool than warm.</p>

[mal_thomas]

<p>Thanks for all the feedback. Appreciated.<br>

Using Ilford's own tables of development times, it seems I can reduce the dev time for FP4+ to 05:00 mins at 24C/75F (currently using LC29 at 07:30, constant rotation, 20C/68F).<br>

But if I change to DD-X, their own Development Chart states I can go 08:00 mins at 24C/75F (for FP4+) - no conversion necessary.<br>

It drops down to 05:30 for Delta 400 too - which is what I am hanging out to develop. How lucky is that ? I just bought a bottle of DD-X the other week :-)<br>

I need to run some tests methinks.</p>

<p>Cheers<br>

Mal<br>

Oz</p>

[steve_mareno1]

<p>My kitchen has two sinks. One is used to catch the drips from inverting the developing tank (grr), and the other sink has a few inches of ice water w/ ice cubes floating around in it. That's where the chemical gradients sit w/ thermometers in each of them. When they get to the right temps, they come out of the bath, sit on the counter, and I start my developing. I've set the developing tank back into the cold water in between inversions, and not done it. No difference in the negs, and this is in Florida where it is often pretty hot in the home. </p>

[glen_h]

<p>To summarize, it is the temperature of the chemicals that matters. If the air is hot or cold, it will eventually bring the chemicals to that temperature, minus evaporative cooling. </p>

<p>I put my tank in an 8x10 print developing tray to catch the drips. I think the biggest loss of Diafine, which pretty much doesn't wear out, but eventually you don't have enough left, is drips. </p>

<p>But then again, with Diafine I don't have to worry about the temperature at all, between 70F and 85F. As well as I know, it develops close enough to the same at all those temperatures. </p>

<p>I also never worried about the temperature for black and white print developing. Find the exposure for 60s or 90s at the current temperature, usually between 65F and 75F for me.</p>

[mpo]

<p>If you are willing to spend some money, you can end all your troubles buying a Developing Timer with Temperature Compensation like this RH Design <br>

http://www.rhdesigns.co.uk/darkroom/html/processmaster.html<br>

It's all you'll ever need, I bought mine six years ago and I completely forgot about temperature issues.</p>

[mal_thomas]

<p>Great little gadget there Marcelo, but as you inferred a little pricey - AUD$400 buys a lot of film :-) <br>

Also the probe wont fit into my tanks (I have never used Patterson tanks for developing my films).<br>

Appreciate the link :-)</p>

<p>Cheers<br>

Mal<br>

Oz</p>