How much liquid to fill in B&W developing tank

[roy_ramavarapu1]

<p>I am new to B&W film developing by myself/at home, and am getting started; please be patient with my questions. I have not developed any yet. I must write that this forum is an awesome resource for all kinds of information for the novice to the advanced levels, and I thank everybody who contribute their experiences.<br>

I will appreciate quantitative information for my question, please. I have a developing tank and insert two 35mm reels. I notice that the inserted reels leave a height of 0.9mm of free space to the brim/edge of the tank; the 0.9mm is measured from the spiral surface; this height is 0.5mm if measured from the rib on the spiral. All these heights are without the lid & cap placed. To complete the information on the heights, the height of this tank from the inside bottom to the brim/edge is 86mm (=8.6cm). I would think that the 0.9mm height is more important to consider as the film (wound into the spiral) ends at this height. I must also take into consideration that the developing liquids in this free space will be compressed when the tank cap lid is placed - some of the developing liquids could enter (due to the lid compression) any available free space in the tank lid baffle regions, and may even flow out the pour spout (this is covered with the cap). <br>

A related question: should there be free volume (empty space) inside the tank (with the lid and cap placed) to allow the developing liquid to move around when the tank is inverted. I also realize that any free volume at the top of the reels will be transferred to the bottom of the tank when the tank is inverted. Is this free volume and movement of the developing liquids required/a good practice, OR, should there be no free volume, no movement of the developing liquids, and the films stay 100% immersed ALL the time. [The feature of free volume would be resolved if only one reel has film, and the second reel is blank - that is, develop one reel only in the tank - this would be wasting chemistry, I think. However, the feature of fluid movement still remains].<br>

The same questions as above but this is for the case of the tank with one single reel only. With the reel inserted, the height from the spiral surface to the brim/edge of the tank (without the lid & cap placed) is 10.0 mm (= 1.0 cm). The same height but from the rib is 0.7mm. The height of this tank from the inside bottom to the brim/edge is 49mm (=4.9cm). The tanks and reels are same respective manufacturers. <br>

The same question also please for the case of 120mm film spiral. The tank I have has one 120mm spiral, and the free height to the brim/edge (without lid & cap placed) is now 16mm (=1.6cm) from the spiral surface; this height is 14mm (=1.4cm) from the rib. The tank height from the inside bottom to the brim edge is 81mm (=8.1cm) without the lid & cap placed. Please note that there is a lot more free volume in this case, and is the source of my questions: how much liquid to fill, and should there be movement of liquid inside the tank OR 100% immersion all the time. PN: this 120mm tank and reel are also same respective manufacturers as above.<br>

Thank you all very much, and your information will be deeply appreciated.<br>

Best regards to all.<br>

Roy Ramavarapu, 11 Jan 2014</p>

<p> </p>

[pics]

<p>Some free space isn't a problem in my experience. The slight amount of time the film may be exposed to air during agitation wont affect anything. I think a little air space helps ensure more complete agitation and helps facilitate the even spread of developer throughout the solution. The important thing is that the film is completely submerged when the tank is in the upright position in between agitation cycles. Also important is consistency. Before using a new tank, I place the empty reel (or reels) in it and then fill with water until the reels are completely submerged (plus a little extra to be on the safe side and account for spillage etc..). Then I measure this amount of water in a separate beaker/graduated cylinder and that is the total volume of mixed developer I will always use with that reel/tank combo.</p>

[bgelfand]

<p>Put the reel(s) in the tank, With the lid off, pour in water until the reels are fully covered. Pour the water into a measuring graduate. Read your answer from the graduate scale.</p>

<p>Yes, film will take some space, too. For a more accurate measurement, load the reels with film (either developed film or sacrificial rolls) before you pour in the water, but empty reels should suffice.</p>

<p>Yes. leave room for the chemicals to circulate with the lid on when you agitate. </p>

[john_shriver]

<p>Yes, definitely there should be air space in the tank, so that the agitation will move the developer around.</p>

[Rick Helmke]

<p>If you are using stainless steel reels you you should need 8 oz. per roll.</p>

<p>Rick H.</p>

[roy_ramavarapu1]

<p>Thank you very much for the superb and quantitative answers to my question(s). I will measure the amount of water as described (I have to use empty reels as I have only two sacrificial rolls of 36 exp film to practice with), and will note the data on each tank - I stick masking tape to the tanks, and write on them. I find this writing is necessary because the same kind of tanks/same manufacturer have slightly different sizes - this was pointed out in one of the threads in this forum.<br>

Also, I think the 120mm reel would need to be held in place in the tank with something stainless steel (plastic (Lego blocks??) may react with the chemicals) so that it won't move (actually slide up and down and possibly dislodge the film) during inversion/agitation. Thank you all again very much.<br>

Roy Ramavarapu, 11 Jan 2014</p>

[thirteenthumbs]

<p>The film, regardless or size or film format, must be fully covered with solution if doing inversion or stand development.<br>

Air space increases the chance that air bells will form on the film during development resulting in pin holes in the finished negative.<br>

I have filled any tank that I used for inversion processing anywhere from the base of the fill opening to top of the fill opening with no adverse effects or modification of time necessary.<br>

<br />Keep your chemical temperature constant and within 1°F of one another for optimal results, within 3°F for acceptable to very good results. A temperature difference of 5°F or more may cause problems. This includes the rinse water.</p>

 

[pics]

<p>There really isn't a way to completely ensure that air bubbles aren't induced into the developer, even if the tank is filled all the way to the top. The simple act of pouring the developer into the tank can cause them. One trick I learned (can't remember from whom or where), is to give the bottom of the tank a sharp knock against a hard surface (counter top etc.) at the end of every agitation cycle. Doing so should dislodge any air bubbles that may adhere to the surface of the film. I can't say whether or not it makes a difference and often times I forget to do it, but I've never had a problem leaving some airspace on the top of the tank. You also don't need to secure the reels inside the tank with anything unless it is some oddball style tank that calls for a design like this. As long as the reel can move up and down freely and readily settles to the bottom when the tank is placed in the upright position, you are ok. Once again, along with some airspace, the reel moving back and forth during inversions helps ensure thorough agitation and movement of the developer.</p>

[JDMvW]

<p>Since tanks differ in size and capacity, do as Brooks says:</p>

<blockquote>

<p>Put the reel(s) in the tank, With the lid off, pour in water until the reels are fully covered. Pour the water into a measuring graduate. Read your answer from the graduate scale.</p>

 

</blockquote>

<p>Since any excess will spill over, it's better to have too much rather than too little. Rap the tank, as said, to knock any airbubbles loose.</p>

[cj8281]

<p>It sounds as if you have a stainless steel tank. A plastic tank has a center core and a snap ring that will hold a single roll on the bottom of the center core. <br>

A stainless steel tank has no such center piece. For my 2 reel Nikor tank (stainless steel) for 2 35mm reels it requires 16 ounces (475ml) of chemistry, for a single 120 reel it only requires 15 ounces (450ml) of chemistry. If you are going to develop only one roll of 35mm film in a 2 reel tank, I would put the second empty reel on top and only use 8 ounces (240ml) for the single roll of film. The second empty reel will help keep the reel with the film loaded on the bottom. I sometimes notice that the reels may get stuck and not move around when I am done with an agitation cycle, a simple rap on the counter gets them freed up and settled on the bottom again. A rap on the counter is also recommended at the initial pour in to dislodge any air bells from the film.</p>