Film      Developing


Here are some notes on developing 120 film with the Paterson tank.

Reader-Supported Site

Articles like this one are possible only with the support of readers like you, when you use the links on here to purchase your gear. 

Your help lets me keep this site going.   Thank you in advance!

Before You Start

If you just ate a Mexi-Melt bagel with three kinds of delicious greasy toppings, I would suggest thoroughly cleaning your hands.  You want them to be good and dry, because grease and oils will block the developing chems somewhat.  And 120 film does not guide itself onto the reels that easily.

Clear out the dust bunnies and lint from your darkroom floor, because there's a chance you'll drop the roll while trying to finagle it onto the film reel.

Table of Contents

Loading 120 Film

This can be a lot more difficult than loading 35mm film. 

Allow more time than you think you'll need.  It could take you twenty minutes to get that 120 film onto the reel, if you haven't done this before.  Or, if you're just out of practice. 

Why so difficult?  As usual, this has to be done in total darkness.  In addition, it's harder to get both edges of the film into the guides and keep them there. 

You also have to deal with the backing paper.  Again, this all has to be in total darkness.  I would recommend separating the film from the backing paper altogether before you try getting the film onto the reel.  It can probably be done the other way, but nah, too complicated.

You'll probably crinkle the film at some point, leaving marks that cannot be removed.  This often happens to the first picture on the roll. 

While you try to get the edges into the guides on the reel, the film will try to buckle across the width of it.  Try to support this middle region, because otherwise the film edges will not reach the film guides.  And most of all, take your time.  The moment you start getting flustered, and wanting to "just make it fit", you will ruin the film.  Or it will fall on the floor.

Sometimes you can guide one corner of the film, get it attached, and then guide the other corner, without crinkling up the film.  Hate to say it, but this is one procedure you're just going to have to practice a few times.  Don't try to learn this procedure with a critical set of wedding pictures.

Table of Contents

Developing Notes

A roll of 120 film uses the same amount of developer concentrate as a roll of 135-36.  Six milliliters of HC-110;  not sure about other developers.  (Somewhere on this site I have notes about Ilfotec DD-X, also.)

However, it takes about 500 ml of liquid to cover a roll of 120 in the Paterson tank. 

So, if you're using HC-110 Dilution B, this will contain more concentrate than needed for one roll.  This is why I recommend mixing up one liter, then returning the used 500ml back to the one-liter container when you're done.  For the next roll you develop with this, use the method I describe in this article.  I've also worked out a similar method for color negative film

In summary, a roll of 120 uses the same amount of developer as 135-36.  Only difference is that you have to use more liquid to cover the film in the Paterson tank. 

Table of Contents


This was just a few notes on developing 120 film with the Paterson tank.  I may add to this article as I think of other stuff that might help you.


If you found this page useful, informative, or entertaining, please help me out by purchasing any of your gear through these links.   Your help is greatly appreciated;  it allows me to keep this website on-line and adding more articles to it.

Thanks for visiting this page!

Contact me:

3 p o.t o . 1 2 0 s t u d i o.. c o m

This won't directly copy and paste.  Please manually type it into your mail program.
No spaces between letters.

Home Page

Site Map


Copyright 2018.  All rights reserved


Back to Top of Page