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DIY machine for agitating method replacement

Wednesday, December 30, 2009

since i start to develop my film by my own, my craziness is influence in my developing tank too.

Manual Developing film will be doing a standard action, agitation. Whether you do a rotating the film or turn up side down, you still have to agitate. You will have to concentrate on your agitate to get a good result. And the result are depend on your agitation, each people develop film with his own way. You cant leave your room, you cant take a phone call, you cant even smoke, otherwise your film will be ruin.

Why we need to agitate?

Here's why:

The only developer doing that's actually doing the work of developing is that which is in contact with the film. After a developer molecule has reacted with a silver halide, it is used up-it can no longer react with the silver halides.

If the developer is not moving, the molecules won't move around very much. This means that immediately above the areas of higher density, the concentration of unused developer molecules drops off, and the rate of development slows down very dramatically. This means that areas of high density essentially stop developing.

The problem doesn't exist as much in areas of low density, as there aren't nearly as many silver halides reacting as to exhaust the developer. Thus, in areas of low density, developing continues at a greater rate than it does in areas of high density.

Thus, over the course of the development time with no agitation, the shadow areas will get more development than the highlight areas, resulting in lower overall contrast.

Conversely, agitating provides a continual supply of fresh developer to the surface of the film. By agitating once every thirty seconds or so, you are keeping the amount of development essentially the same for all areas of the film.” Taken from Ben H at yahoo answer.

I don’t like this, I am not a patient man, I like to cut my film so I don’t have to wait for 36 roll finished, I even cut the developing time from 8 minute with 20 celcius to 4 minutes in 30 celcius. I still like the result.

And the agitating process of course is the most thing that I don’t like. I don’t want my developing result depend on my emotion. I want to create a simple machine.

The first thing is I want to make a rotation motor to move my dev tank. But I read some article about agitating continuously will create effect bromide drag, Bromide can drift downwards during some conditions causing streaks, if agitation is insufficient. It can move opposite to the agitation direction if constant unidirectional agitation is applied.. The jobo machine are rotating continuously, but very slow. Well creating motor with very slow rotation means lot of gear and calculation. Its not suitable with my craziness too.

So my idea is shaking continuously. Just a Smooth shaking.

I took my motor on broken massage machine (he he he, it's not broken but I destroy it to understand how the vibration created). Actually it just a simple motor with unbalance weight, so the motor will shake when rotate, its so simple idea. And I have to destroy it to understand the method.

And how to attach it, just glued the motor on the red cap ( if you have a dev tank like me) powered the motor with nokia mobile phone charger and the dev tank will shake smoothly. If you look at the water inside it you will see a small wave and the water are slowly rotating too.

Let’s talking about the result

first test using a exhaust chemical ( been used for six time)

no phothosop adjustment

Good enough for me, and the good thing is you don’t have to agitate. All you have to do is set the alarm, and pouring the chemical when the time is come. You don’t have to concentrate, if you use a glove, you don’t have any contact with chemical at all. you are still can eat or do something between developing process. But you still have to do washing process manually, but it just put the dev tank on running water. No big deal.

The good thing is, this idea good for push processing. Taking longer time on developing film will make our hand tired, will you stir or turn upside down your tank for 30 minutes in full concentration??? I won’t do that. I know somebody did it. But it won’t be me. here some of the result using canonet, and fuji neopan iso 100

second test, crazy idea, shoot with speed 1/125 indoor with room light.

third test, new year party (with photoshop adjustment)

canonet f1,7 s= 1/30 NO FLASH, neopan 100, dev 30 minutes at 30celcius

canonet f1,7 NO FLASH, s 1/30 neopan 100, dev 30 menit at 30celcius

canonet f1,7 NO FLASH, s= 1/30 neopan 100, dev 30 menit at 30celcius

canonet f1,7 NO FLASH, s= 1/30 neopan 100, dev 30 minutes at 30celcius

canonet f1,7 NO FLASH, s=1/30 neopan 100, dev 30 minutes at 30celcius

canonet f1,7 NO FLASH, s=1/30 neopan 100, dev 30 minutes at 30celcius

just hoping somebody try my idea and tell me the result, i will be glad if somebody give some input and comment.


  • dustrivER says:
    February 4, 2010 at 2:28 AM

    bos, maturnuwun buat artikel2nya. sangat membantu. khususnya yang 1 ini.

    triknya asik2. aku dah nyoba yang developer tank. lumayan tangan ga pegel. eh bos, kapan2 bikin enlarger yg DIY dong. hihihihii request ah..

    oiya. aku topan, dari purwokerto.