Darkroom Tutorials Black and White Film Processing Using Paterson Tanks

Processing black and white films is straightforward but you do need to be careful with timings, temperature, dilutions and agitation. If these vary your negatives will be inconsistent in quality from film to film.

You do not need a darkroom to process a film but you do need a way to load your films into the processing tank in the dark. The simplest way is using a light-tight changing bag. Alternatively you can use any room, or even a cupboard, provided it can be ‘blacked out’ to stop light entering while the film is loaded into the developing tank. Once this is done, the rest of the process takes place in daylight.

Processing involves 3 simple steps, develop – stop bath – fix. It takes about 20 minutes from the start of development until the processed and washed film can be hung up to dry.


To process black and white film you need some equipment.

Paterson developing tank and spirals (also called reels)

plastic measuring cylinder

plastic tubs or buckets for diluted chemicals


clock or stopwatch

film clips


negative storage sleeves

Of these, the Paterson developing tank is the most important. The tank keeps the film in total darkness even in daylight. The screw lid and spindle on which the spiral is mounted mean that chemicals can be poured into and out of the tank without light exposure to the tank contents.

Film is loaded onto a spiral reel and this ensures the solutions reach every part of the film surface.

Label your plastic tubs or buckets so that they are exclusively used for just one diluted processing solution.

Always follow the specific health and safety recommendations on the chemical packaging.

Processing Chemicals

I use the Ilford chemicals listed here. They are easy to mix and use because they are all supplied as liquid concentrates.

Ilford Ilfotec DDX developer. Mix only as much as you need to completely cover the spiral in the developing tank with solution: 300 ml per 35 mm spiral or 500 ml per 120 or 220 spiral. The Ilford recommended dilution is 1 part DDX + 4 parts water (I use 1+6).

Ilford Ilfostop stop bath brings development to an end and prolongs the life of the fixer. Diluted 1+19 (50ml Ilfostop/litre water)

Ilford Hypam fixer makes the image permanent. Diluted 1 part Hypam + 4 parts water.

Ilford Ilfotol wetting agent in the final wash water ensures that the film dries quickly and evenly. Diluted 1 part Ilfotol + 100 to 200 parts water (5 to 10ml Ilfotol in 1 litre water).


During development, temperature control is important, and you must use a thermometer to make sure the developer is not too hot or too cold. Temperature is not as critical with the stop bath and fixer steps, or during washing but should be within a few degrees of the developer temperature.

Detailed information about these films and other Ilford products is available at www.ilfordphoto.com.


Ilford have an extensive range of products but these are the films that I use for all of my landscape, city and skiing photography.

Ilford FP4 Plus

For high quality landscape photography Ilford FP4 Plus is unbeatable. It is an exceptionally fine grain, medium speed, black and white film that I always rate at 125 ISO.

Ilford SFX 200 infrared film

Ilford SFX 200 is a black and white film for infrared photography. It has extended red sensitivity up to 740nm and using an infrared filter such as the Heliopan 715 or Hoya R72 skies can be rendered almost black and green vegetation, excluding conifers, almost white. I only use it in bright sunshine as this is when plants give off most infrared. I rate it at about 6 ISO when using the infrared filters and process it identically to FP4.

Loading the spiral

Pick up the spiral and find the lugs that stick out on either side of the inside faces. This is where your film is fed in to the spiral. Keep your thumbs on these as you pull the film onto the reel through these. Rotate the sides of the reel back and forth to wind the film into the spiral. Continue until you reach the end of the film, then cut this away from the 120 wrapper or 35mm cassette spool. Wind the film completely onto the spiral.

The grooves of the spiral hold the different parts of the film away from one another, so that the developer can circulate freely. If the film is not loaded correctly uneven development causes damage to negatives.

Finally, put the spiral into the developing tank, screw on the tank lid and push on the flexible sealing cap. The film is now inside a light-tight container and you can switch on the room lights.


Remove the sealing cap and start development by quickly pouring the Ilfotec DDX developer into the tank. The developer temperature should be within a degree of 20°C. Start the timer when all of the developer is in the tank.

Fit the tank sealing cap and turn the tank upside down 3 or 4 times during the first 10 to 15 seconds. Repeat this at the start of every minute to agitate the developer. Also, each minute after the inversions tap the tank to dislodge air bubbles on the film.

For me, Ilford FP4 Plus film needs 9.5 minutes in Ilfotec DD–X at 1+6 dilution at 20°C. Start to pour the developer out of the tank about 15 to 30 seconds before the end, depending on tank size. Developer is not re-used.

Stop bath

Pour the Ilfostop stop bath solution at 20°C into the tank. Agitate by turning the tank upside down twice. After 10 to 30 seconds, pour it out. The time in the stop bath is not critical.


Zero the timer and pour in the Ilford Hypam at 20°C. Start the clock as you finish pouring, then agitate by inverting the tank 2 or 3 times every 20 seconds or so, until fixation is complete at 4 minutes.


Now the film is fixed remove the tank lid. Use a piece of tubing to feed running water above about 6°C down the centre of the spiral to the bottom of the tank. Wash the film in running water for about 5 to 10 minutes. I also completely empty the tank every minute and refill from buckets of water at 20°C.


Finally, pour rinse bath into the tank to cover the spirals. Allow 30 to 60 seconds for the wetting agent to work. Lift the film spiral out of the tank. Pull the spiral apart by twisting it, or pull the end of the film out of the spiral, and attach a film clip to it. Hang the film from a drying line.


Attach a weighted film clip to the bottom end of the film. Leave it to dry in a still, dust-free atmosphere. Drying can be speeded up by using a film drying cabinet.