3.25 minutes

<p>I will be developing my first color neg. film soon. The chems are on the way. When I develop bw film it takes about 10 to 15 seconds to empty the tank at the end of development (and about 10 to 15 sec to fill the tank). Kodak instructions for tmax always say that development times shorter than 5 min may produce unsatisfactory results. I develop bw at times somewhat longer than 5 min and even tho my times are not exactly as the Kodak chart suggests, the results have been fine. However, with c-41 process, the development time is 3 minutes 15 sec. This short time has all the makings of consistent dis-satisfaction with the result due to the imprecision of the timing (+/- 10+ secs.). How do you make the times precise? Is it possible to lower the temperature by 30 degrees F or so, and use a longer time <em>with results every bit as good as the preferred higher temperature? </em></p>

<p>I am using Tetenal C41 chemicals for the first time and the instructions show different processing times for three different temperatures.</p>

<p>Standard development at 100 degrees is 3 minutes 15 seconds<br>

Longer development at 86 degrees is 8 minutes<br>

Rapid development at 113 degrees is 2 minutes</p>

<p>You will get the best results at full temperature, 3 minutes, 15 seconds. You will get "off" color curves at any other temperature, as the process is designed around exact diffusion rates through the many layers in the emulsion.<br>

The shorter time is OK because the temperature is a lot higher, so the developer will diffuse in quickly.<br>

Ideally you should fill the tank with developer, drop in the reel of film in total darkness, and put the lid on. But filling it through the spout should work OK as well.</p>

<p>The way I would do it is to start filling so that when your clock hits 3:15 you are just full, then when emptying, start pouring out so that when the clock hits 0 the tank is empty. That means, practically, starting in flow at 3:25, and starting out flow at 0:10.</p>

<p>But John's method, using two tanks, one for the dev to drop the film into and another ready for the next step, and make the changes on the spot of the clock, is best, if you have a dark place to do the switch.</p>

<p>The basic rule is, if you're always going to do it "wrong" at least do it exactly the same wrong each time.</p>

<p>I always process color by timing from when the tank is full to when I start to dump it. Always get excellent results. The extra 10 to 15 seconds does not have a noticeable affect. I have compared my processed negatives to those processed by a high end pro lab, no noticeable difference.<br>

Keeping the temperature within 1° of the desired temperature is critical.</p>

<p> If I understand you correctly, Charles, you pour in all the developer, then start the timer, time for 3' 15", then pour out the developer then pour in blix. It seems to me that adds nearly 20 seconds of development. It takes me about 10 secs to pour in and 10 secs to pour out. Even with all the developer out, it seems to me there is still residual development going on until the blix is added. I'll try it your way anyway. I intend to presoak at slightly higher temp. </p>

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<p>If I understand you correctly, Charles, you pour in all the developer, then start the timer</p>

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<p>Correct., time for the desired time, pour out, proceed to the next step.</p>

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<p>Even with all the developer out, it seems to me there is still residual development going on until</p>

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<p>Development will continue until the developer absorbed by the film has exhausted or has been stopped by another agent.</p>