maintaining temps

[kavin_k]

<p>i decided to develop c41 at home and im getting ify results its not consistent every time my big issue is maintaining the proper temps, is there some sort of device i could use to maintain the water bath at a consistent temp? love developing at home since its fast I just need to figure out a way to make everything consistent</p>

[Sandy Vongries]

<p>Large fish tank heater -- good ones are rather precise.</p>

[kavin_k]

<blockquote>

<p > </p>

<p ><a href="/photodb/user?user_id=9277660">Sandy Vongries</a> <a href="/member-status-icons"><img title="Subscriber" src="/v3graphics/member-status-icons/sub1.gif" alt="" /><img title="Frequent poster" src="/v3graphics/member-status-icons/3rolls.gif" alt="" /></a>, Nov 04, 2016; 10:29 p.m.</p>

 

<p>Large fish tank heater -- good ones are rather precise.</p>

<p>Im actually a pretty big aquarium hobbyist myself, very interesting idea, but most of my heaters on go up around 90F for my kit its recommended 102F</p>

 

</blockquote>

[bebu_lamar]

<p>Constant temperature water bath isn't difficult to make any more due to inexpensive temperature controllers available today. However, even with constant water bath the chemical temperature is not constant. </p>

[JDMvW]

<p>We used to immerse the chemical mixture containers into a constant temperature water container. You have to start early to get things stable, of course, and monitor the temperatures before starting. If different temperatures are involved for different parts of the process, it got overly complicated and difficult.<br>

I'm afraid all my C41 stuff goes to Dwayne's nowadays. My slap-dash methods work OK for Tri-X and D-76, but .....</p>

[PapaTango]

<p>The key to water bath control is ensuring that the volume circulates--for equalization of the temperature in the entire volume. I tried immersable heaters and ended up with one end of the bath container far to warm compared to the distant side. Then I added a little recirculator pump (the sort used on small tabletop decorative waterfall windmills) and decided I had too much junk involved--a more elegant solution was called for.</p>

<p>Tried and true is the supply line flowing water method. It does not take very much more than a small stream to keep temperature constant. Here, a temperature gauge is attached to a faucet, and a hose inserted into the chemical container. Styrofoam ice chests work best as a "tank" as there is minimal loss. Here is an example of such a regulator and the best price I could find:</p>

<p><a href="http://www.adorama.com/dkwt2.html">http://www.adorama.com/dkwt2.html</a></p>

<p>Around $100-125 builds a nice, basic system. Mine is a Beseler, which in no longer sold. </p>

[glen_h]

<p>I did E6 some years ago (not long after it came out) with water baths in large print developing trays. I would fill them about as much as I could so that the tank wouldn't float too high.</p>

<p>A separate tray had plastic containers like you use for leftovers in the fridge, that have lids and you buy in grocery stores. Each chemical step goes in one, labeled so I don't forget which is which.</p>

<p>I had bowls of cold and hot water that I could pour into either tray. If the trays were the right temperature, and the chemical I was about to add was right, then I poured. There are two steps for E6, and one for C41 that you really need the temperature right. The rest should be close, but don't need to be so exact. </p>

<p>The C41 developer time is only 3:15, which with enough water, shouldn't be hard to keep the temperature close. A little more warm water in the water bath would help be sure. </p>

<p>The E6 times are longer, so one has to work harder to keep the temperature up, especially in a cold darkroom.</p>

[dhbebb]

<p>At one time I acquired several large dish (tray) heaters. These were so large that I had room for trays holding several jugs of chemicals and also several developing tanks. As a general rule, of course, metal tanks will conduct heat better than plastic ones and thus change temperature faster, on the other hand Paterson tanks have a facility for inserting thermometers during processing, which means you can immediately correlate the water bath temperature to the temperature inside the tank (bath might need to be one degree or so warmer). </p>

[donald_miller5]

<p>in the beginning i really obsessed over the temperature with a lot of labor intensive ideas. Now I just use a large bucket and getting better than when I started.. What made the biggest difference was making sure the chemicals were the right temperature. I use thick glass bottles so I let them sit in the bath for extended time while maintaining temp. For the short time that I actually use with the tank I found negligible variation in temperature. even if you take the tank out to invert it. Even if the bath drops by 1 degree over this short time the solution temperature change in the developing tank would be lagging. Also like Patrick said you want to avoid standing water. I found along the way surprising temperatures variations between top and bottom.</p>

[Ed_Ingold]

<p>Temperature is critical only for the first (development) stage. Thereafter it's important to keep temperature swings as small as practical to avoid thermal shock on the emulsion, and to assure the chemistry runs to completion.</p>

<p>For years I used a styrofoam box (used to ship sulfuric acid bottles) salvaged from the chemical supply room. I would mix hot and cold water, with good stirring, to reach the correct temperature (75 deg F at the time), and it would hold well enough throughout the process. I find that 100 deg F is more challenging, but still practical in this manner.</p>

<p>For a few hundred dollars, you can buy a thermostatically controlled mixing valve, which automatically tempers flowing water. At the newspaper, we used a large, shallow sink with a standpipe, which would keep the water level at about 3". Since the water was continuously flowing, stirring and spills were never an issue.</p>

<p>Again, for a few hundred dollars, you can (or could) get a rolling tank setup which used a thermostatically controlled water bath. That would be the best solution for home use, because it fits on a table top. In the old days, we needed cooling as much as heating. Now, at 100F, heating alone will suffice. A static, tempered bath is probably all you need for B&W processing, which has a lower set point and wider tolerances.</p>

<p>It takes a very long time to temper large bottles of solution, and a much deeper bath to provide adequate coverage. Stirring (or shaking) is necessary to achieve any sort of uniformity. If you use the same bath for developing, you need a stable platform so that you don't completely immerse the developing tank. At the newspaper, color chemicals were used in stainless steel dip tanks, sitting in a tempered water bath. For that you need a darkroom. A possible compromise would be to pre-measure solutions into metal containers, kept in the same bath used for developing.</p>

<p>Rinsing is going to be a problem. Don't even think about using a kitchen faucet to temper water. If someone flushes, your film might end up with a crinkle finish. I just used cold tap water, with a final dip in Photoflo and distilled water.</p>

[euangray]

<p>When I started developing my own C41 last year I worried about temperature but other than for the developer stage it really isn't as critical as some make out. 38 Celsius for 3 minutes 15 seconds for the developer, the rest can be anywhere from 30 to 40 Celsius. As with black and white, only the developer stage is critical. It isn't hard to keep a bath stable for under four minutes.</p>

<p>I use a Novatronic 150W submersible heater, which easily handles the job and is designed for it. You can get them from Firstcall Photographic here in the UK for £49. Once adjusted to the right temperature (a bit of trial and error), they're pretty accurate and consistent. Note that the larger the water bath the slower it will lose heat - but equally, the longer it will take to heat up. Use a plastic box for the bath rather than metal, plastic is a much better thermal insulator. </p>

<p>Don't rush the process. Allow the solutions to come up to temperature in their own time. Buy a precision thermometer and measure the temperature of the developer directly, not just the water bath temperature.</p>

<p>A further tip for consistency is to NOT use any developing kit which contains "blix" or combined bleach and fixer. These two solutions are antagonistic, they destroy each other. Unless you're going to develop in a very short space of time (i.e. days rather than weeks) the volume of film the kit can potentially process, you're likely to be disappointed with the results. I use the Fuji Hunt X-Press C41 kit, which goes for £45-£50 and gives five litres of each solution including separate bleach and fixer. Although nominally with a shelf life of only a few weeks once made up, the developer (the single sensitive component) actually lasts for months if kept in oxygen-impermeable bottles with no air inside (I use five one litre PET plastic mineral water bottles) at reasonably low temperatures.</p>

<p>Another tip is to note that the bleach and fix processes run to chemical completion. This means the time (nominally 6 minutes 30 seconds for each) is not a hard limit and, within reason, you can leave them to run longer. I give them eight minutes each - remember that time is ONLY critical for developer.</p>

<p>A Fuji kit will develop up to 80 rolls of film. If you won't go anywhere near this total in say six months or so, you may be best advised to save money and send the film to your local lab. That said, even if you only get half the quantity out of the kit before the developer degrades, it's still cheaper than sending out. - and you get the satisfaction of having done it yourself.</p>

[robert_hill11]

Sous vide cookers....works great!

[Wilmarco Imaging]

An insulated box, for example a picnic cooler, works well as a tempering bath. I have measured in-tank temperature of 100 deg F at the end of the fixer bath using this method. No electric heater needed. I use two 1 gallon (4 liters) jugs of hot water as "heat batteries", or emitters, in the tempering bath.

[glen_h]

Note that it isn't necessary that the temperature be right through the whole (only) 3:15. If you get the average temperature right, it is usually close enough. (You can't average 120 and 80, but if it goes from 105 to 95, the average 100 is close enough.)

 

For my E6 days, I had, I believe an 11x14 tray close to full for a 35mm (single reel) metal tank. That is deep enough to cover most of the reel.

 

Another 11x14 tray with water holds the solution for each step in plastic containers with lids that you buy in grocery stores for holding food.

Those keep the chemicals close until time to pour. For developers, measure the temperature inside the container just before pouring, and the water bath is close.

 

I had a bowl of hotter water that I could add some to the water bath, to quickly change the temperature.

If the bath is 1 degree cool, adding 10% of 10 degree hotter water, or 5% of 20 degree hotter water, will get it close.

Estimate the volume, and scoop away.

 

Over 16 rolls (two kits) I never had color that I thought was off due to processing.

[bebu_lamar]

Tempering bath is quite easy to build. I use a roaster oven and build a temperature controller that I plug the oven in. Edited June 23, 2017 by bebu_lamar

[tomspielman]

Yes, Robert and Bebu.

 

I used a roaster oven I found at thrift store along with a raspberry pi, a temp sensor, a relay, and a cheap aquarium pump to build a Sous vide / water bath

 

Great for cooking steaks and processing film !

 

If you're not into electronics or programming you can just buy a Sous Vide. They're not terribly expensive. Basically you use them to slow cook steaks (and other stuff) by sealing the steaks in bags, then immersing them in water whose temp is precisely controlled.

 

You cook film at much lower temps than steaks but it works well for both.