Making a film developer

Before we absorb the alternative photography process it was key to understand the non alternative or simply speaking  the regular photography process of  B/W developing so we learnt how to make a developer  for  B/W film from scratch. Here is how to go about it.

We tried to make a developer close to the Kodak D 76 film developer. This developer is good for low contrast and maximum shadow detail. The commercial product,marketed by Kodak, is the world’s best-selling black-and-white developer and the ingredients needed for that  can be bought at a local chemical store as they are used in various  other  industries. The chemicals required  are –

-Metol

-Hydroquinone

-Borax

-Sodium sulfite

Essentially a B/W film is a transparent plastic sheet coated with an even layer of gelatin in which silver chloride and silver bromide are dissolved and act as the light sensitive coating. So during an exposure on film the light hits this light sensitive silver chloride and silver bromide and sends them into an excited state thus loosening  the bond between them. Thus areas that received more light i.e the highlights get more light and thus are more excited and the shadows received less light or no light and accordingly are less excited or not excited at all. The main function of a developer is to remove these loosely bonded chloride and bromide and leave the silver to form a negative.

So metol and hydroquinone  are essentially reducing agents meaning they remove the chloride and bromide. Metol is a soft reducing agent and hydroquinone  is a hard reducing agent. They are added  in 2:5 proportion. For the reducing agents to work there needs to be an alkali present which acts as a catalyst  in this case it is Borax. For the developer to not go bad during the process i.e essentially to stop the reducing agents from reacting with the oxygen dissolved in water we need to add a preservative which in this case is Sodium sulfite. Finally we need a restrainer in the developer so that the developer does not affect the non excited silver chloride and silver bromide. All these put together in the following proportions give you a developer for B/W films similar to the Kodak D 76 Developer.

Water at 125F/52C, 750.0 ml

Metol, 2.0 g

Sodium sulfite, 100.0 g

Hydroquinone, 5.0 g

Borax, 2.0 g

Water to make 1.0 liter

Dilute 1:1. D-76 may be used undiluted, but there is no advantage in doing so. The negatives while slightly finer grained do not exhibit the same degree of sharpness or tonal scale. Development times are available from most film manufacturers.

 

Variations on D-76: The packaged Kodak formula contains a number of additional chemicals to prevent the metol from deteriorating in the presence of the sodium sulfite and enable it to mix easily in all types of hard and soft water. This allows the formula to be sold as a single package.

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