Using Paterson Developing Tanks

This article is about the Paterson Super System 4 film developing tanks. Except for the photograph of the film reels, the illustrations are directly from the Paterson instruction sheet. The instructions are a bit thin, so I decided to elaborate on them. This will only be useful to someone who has not used the tanks before. After using them one or two times, the instructions will not be needed.

 Adjusting the Film Reels

The plastic film reels can be adjusted to accommodate three film sizes; 35mm,126/127, and 120/220. To adjust the width of a reel, firmly turn the two sides clockwise until you hear and feel a click. The click indicates that the two side of the reel are unlocked. Adjust the two sides to the required film width. Turn the two sides of the reel firmly in a counter-clockwise direction until you feel and hear them lock back into position. The photo here shows the reel on the right adjusted to accommodate 120/220 film. The reel on the left is adjusted to fit 35mm film.

Loading the Film Reels

The instruction sheet included with the Paterson developing tank gives good, thorough directions on loading film onto the reels, but it is also helpful to view this video on loading 120 film. Keep in mind that this process must be done in complete darkness in order to avoid exposing the film to light and ruining it. If you don’t have an area that you can make completely dark, you can use a changing bag. Changing bags are available at online stores such as B&H, Adorama, and The Frugal Photographer.

I found it quite helpful to practice loading film onto a reel with a “throwaway” roll of cheap off-brand 35mm film that I had no intention of ever shooting (think cheap “Lomography” film).  

Loading the Tank

After loading the film onto the reel(s), push the reels onto the center column and place it in the bottom of the tank. Lower the funnel over the center column, then turn it counter-clockwise within the tank until it clicks into position (it will stop). The tank will now be light-tight, so you can turn on the light(s) or remove it from the changing bag.

Lower the agitating spindle into the hole in the funnel. The knurled end should be up. The other end of the spindle is slotted and will fit onto the posts in the center colum to enable moving the reel assembly back and forth to agitate the chemical solutions during the development process.

Press the lid onto the top of the tank. Note: if you are going to develop immediately there is no need to place the tank lid on top of the tank.

Tilting the Tank During Development

The Paterson instructions recommend that you periodically turn the tank upside down with the lid completely sealed on the top of the tank. I haven’t found this to be necessary, since the agitation and tilting the tank to the side seems to take care of circulating the chemical adequately. Use your own discretion about this, but keep in mind that if you upend the tank during development, you will have to seal and unseal the tank top. 

Air Bubbles on the film

It is widely recommended that you periodically pick up the tank and hit it against a hard surface (not hard enough to break the tank, of course) to break loose any air bubbles that may be clinging to the film. I do this every minute after agitating.


After the film is developed, it may be washed while still in the tank. Place the tank (lid off) in a sink, then run tap water directly into the funnel. Agitate occasionally. 


Several instructional videos on loading film rolls are available on the Internet. If the video referred to above is not available, search using the term, “loading film onto developing reels”.

Numerous video and text-based instructions on developing film and making prints from negatives, etc., are also available on the Internet. Just use a search engine like Google, or Bing to locate the information you need.

Different film types require different times during development. Sometimes the times are listed on the film packaging. When the times are not listed on the film packaging, they may be found on Web sites. Again, use an Internet search engine to locate the desired information.