[Frameworks] For KEVIN TRIMMINS-B/W Reversal Process

Laboratory Athens laba_athens at yahoo.com
Tue Jan 17 20:52:06 CST 2012

Hello Kevin, 

I really know what you mean about wrapping your head around the process. It is not too complicated though. 

First of all : keep in mind that when light hits your film the bright parts get 
exposed, the dark do not. When you process your reversal film you (1) 
develop, (2) bleachthebright parts. You 
do nothing to the black parts till then, also not when you (3) clear the bleach. Then you re-expose the "half developed" 
film to light and thus you are "burning" the film and "creating" the 
dark parts. Then you (4) develop this part of the film that you just 
re-exposed and the black parts of your composition finally become dark 
on the film too. Then (5) you fix it. 

This is how it works in some detail (a simple explanation): 

B/W reversal processing has 5 steps as you know, here is what they do. 

Step 1 - First Developer

The first developer develops your film as if it were a
negative. In negative processing the light hits the film and creates 
"black" grain, a negative image. You could fix your reversal film after 
the 1st developer and have a negative film. If you did that to your B/W 
reversal stock you would have "cross-processed it (in
 this case the fixer would make the unafected grains disappear and you 
would have transparent areas on the film where the original image was 
dark -like a negative film should be). 

Step 2 - Bleach

When you developed the film during step 1 you caused a chemical reaction
 to the grains that have been hit by the light, this reaction creates 
dark silver grains. These represent your bright (highlight) areas, of the original image you filmed. By putting your film in the bleach you are 
bleaching away all the dark grains you created in the 1st development 
(it is the bleach really where you REVERSE the film) and what is left 
are the unexposed crystals. If you think of the image you filmed and how the film would look just after bleaching it would be like this: 
-The bright parts of the original image would have almost nothing there 
(first they were developed, made into a black body of grains and then 
-The shadows, the completely dark parts of the original image, would be 
full of unexposed crystals (they had no reaction to the 1st developer 
since no light had affected them and subsequently they were not affected
 by the bleach -which only wipes out the developed grain). 
-The mid-tones of grey would be a mix of the two cases above. 

Step 3 -Clear Bath

Nothing too complicated here: this bath clears away the stains of the pottasium bichromate used in the bleach chemical. 

(This is the second important part for the real REVERSAL of the process). All the unaffected 
crystals (representing the dark in the real photographed composition) 
will be finally affected and become completely exposed, meaning they 
will get BLACK as hell. Important to expose this film long enough. You 
cannot do it too long, you can only do it too short -and too short causes
 dark grey instead of black. Obviously while you hold the film under the
 light you will not see it go black, it needs to be 
developed again. 

Step 4 -Second developer

You now develop the finally exposed grain and create the black part. 

Step 5 - Fixer

You fix and harden the image. 
(it goes without saying, you got to wash between all baths). 

Hope that helped, let us know off list if there is anything you still did not get (and excuse my english) 

Greetings from Athens, 

VB for LabA

PS: While teaching this process we came to understand the fine details and experiment with them and finally we discovered a way to do travelling matte without an optical printer, simply by applying the fundamentals of the b/w reversal process. So you are right to be curious about exactly how it works. 

 From: Kevin Timmins <on-one-2 at hotmail.com>
To: frameworks at jonasmekasfilms.com 
Sent: Wednesday, 18 January 2012, 1:44
Subject: [Frameworks] Black and White Reversal Film Processing


chemical process from first exposure, first developer, bleach bath, 
brain to wrap around the chemical process would be extremely useful to 
me as I want to experiment. 

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