When to Expose my Film During Processing

<p>I had been processing Kodak Tri-X 400 speed Black and White film when my "problem" occurred. I NOW know that you should open the film tank after your second set of chemicals to run water in the tank for a minute, but I ended up forgetting that small detail and opened my tank (with 2 rolls loaded) after I used the developer. I was very nervous at the end of my processing thinking my film would not develop, when in reality, my film ACTUALLY developed great negatives! Lucky me!! Could anyone tell me why this is, whether it's a timing "problem" or a chemical "problem" or if I just got lucky? Thank you!!</p>

<p>Usually it's best to leave the tank capped and protected against light until the negatives have been fixed. This is the safest method to avoid fogging or reversal effects.</p>

<p>However some folks will peek inside the tank during fixing. This probably does no harm, especially with rapid fixer.</p>

<p>I've read a few reports that negatives may be relatively resistant to fogging or reversal effects toward the end of the developing stage, and some folks report no ill effects from inspecting their negatives in room light (not a safe light) after developing but before stop bath or fixing. That seems unnecessarily risky to me.</p>

<p>I do not open the can overall until I'm ready to pour out the fixer. There's a light-tight system for getting liquids in and out for a reason. If there's any issue with getting out anti-halation dyes you might just do more agitation during the fixer step, it seems to get the purple out of my HP5+ anyway.<br>

Standard lab practice in the B&W class I'm in right now is:<br>

Developer (d-76 1:1) agitation for first 30 seconds than 5 seconds ever 30 for the time for that film on the chart<br>

Stop bath or water for 30 seconds of agitation<br>

Fixer agitated like developer for 5-7 minutes. I actually agitate the full first minute then 10 seconds every 30 and my HP5+ is no longer purple.<br>

Fully open the tank and recycle the fixer.<br>

Tornado wash the reels with film on for 5 minutes<br>

Swish them through a bath of (very) dilute photoflo.</p>

<p>Color processing instructions often tell exactly when you can turn on the lights, but it is rare for B&W.<br>

There isn't much reason to open during fixing.<br>

Once the stop bath has soaked far enough into the emulsion so that the developer is acidic, it should pretty much have stopped developing. Even so, there is still an effect from light through the process known as "printing out".<br>

Without development, but with enough light, silver halide will convert to silver. The effect is small enough that scraps of film exposed in the darkroom will normally clear just fine in the fixer, but with enough light, you should see the effect.<br>

Otherwise, many panchromatic films allow use of a #3 (dark green) safelight for a few seconds halfway through development. At this point, much of the sensitizing dye (that makes it red and green sensitive) has washed away. Green is the peak of human vision, so we can see the image with minimal light. I have never actually tried this, though.<br>

(The T-max films seem to have much more dye, and Kodak says not to develop by inspection for these films.)<br>

http://www.kodak.com/global/en/professional/support/techPubs/f4016/f4016.pdf<br>

But not much reason to do it unless you intend to do something based on what to see.</p>

<p>On the other hand, in printing I tend to turn on the lights soon after putting them in the fixer. I have never noticed any effect. Then again, with rapid fixer the fixing is pretty fast.<br>

Ektachrome before E-4 had a reversal exposure during processing. All steps after that could be done with the lights on. E-6 has a chemical reversal step, but doesn't recommend turning on the lights at that point.</p>

<p>Procedure is: dev, stop, fix, wash, open tank. Resist the urge to peek. If there is a problem then opening the tank won't solve it. :)</p>

 

<p>You are not supposed to open the tank until fixing is finished. Fixer is either the second or third chemical depending on whether you use stop bath. Normal order is developer, stop bath, fixer.<br /><br />If you opened the tank after developing but before the fixer and still got good negatives, you just got luck. i'm assuming you had it open only briefly. If you leave developed but unfixed film exposed to light, the image is supposed to fade away. Fixer "fixes" the develped image so that doesn't happen.<br /><br />Whether you got lucky or not, don't do it again. <br /><br />There are reversal processes where you develop the film to the point where you get a negative, then expose it to light before using a "second developer" that turns the film into a positive. But there are other chemicals involved and this is something that was done with slide film and reversal movie film. Not something you do with standard B&W negative processing.</p>