How to Dispose of Darkroom Chemicals

Developing your own films is a great way to get personal with your photography, but cleaning up afterward can be a hassle.

But there’s no need to worry—getting rid of your leftover darkroom chemicals isn’t as hard as it sounds. 

Read on to find out about the different kinds of darkroom chemicals, their properties, and how you can dispose of them safely and easily.

The Three Basic Darkroom Chemicals

There are three basic chemicals used in almost all darkrooms.

These chemicals—developer, stop bath, and fixer—are the bare essentials for developing photographs.


Exposing a film to light produces a latent image. This is an invisible image that forms when the silver halides in the exposed film react with light.

Applying a developer, or a photographic developer, to a latent image will make it visible. The developer does this by reducing the pale silver halides into darker silver metal.

The fresh developer solution is clear and light in color. However, the developer darkens with use and is no longer effective once brown or black in color.

Developer concentrate in powder form has a shelf life of 2–5 years unmixed. After mixing it with water to form a solution, you can expect it to last from 2–6 months.

Princeton University’s Health and Safety Guidelines state that inhaling, ingesting, or allowing developer to come in contact with your skin will cause irritation due to its high acidity.

Stop Bath

A developer will keep working unless stopped, which can lead to an overdeveloped photograph. Stop bath neutralizes the developer and stops the process.

Stop bath has a shelf life of two years unopened, and you can expect it to last around six months after opening it.

Stop bath is only slightly hazardous when in contact with skin but can cause long-term respiratory problems if it is continuously inhaled.


Film will still be sensitive to light even after you have taken your photograph. Fixers prevent any further changes from taking place.

Fixer stabilizes the photograph by removing any unexposed silver halide remaining on the film, preventing the film from reacting to light any further. Fixer also rinses away any other chemicals on the film.

Unopened fixer sealed in an airtight container can last for around three years, but you can only expect it to last around six months after opening it.

Fixer is usually odorless, but if it is giving off a strong scent, then it’s a sure sign that it is now unfit for the darkroom.

Fixer is only slightly toxic by skin contact, but Baylor University’s Health and Safety Guidelines state that heating fixer can produce highly toxic gases, which can cause long-term breathing problems.

Also read: How to Dispose of Old Cameras?

Safety Precautions To Take When Handling Darkroom Chemicals

The chemicals listed above all have different uses, but they also all have one thing in common—they’re all safety hazards.

Before handling any darkroom chemicals, you should ensure you are wearing proper protective equipment. This includes a protective apron, gloves, and goggles.

It is also important to ensure that you keep these chemicals sealed unless you are pouring them, and only handle these chemicals in well-ventilated areas.

If any of these chemicals come into contact with your skin, you should immediately wash your hands. If you ingest any of these darkroom chemicals, you should call a poison control center and seek medical help immediately.

How Hobbyists Can Dispose of Darkroom Chemicals

Since developing photographs at home will only use small amounts of darkroom chemicals, disposal of these chemicals is fairly easy.

However, disposing of darkroom chemicals at home comes with risks and may not be a suitable option for everyone. In that case, a chemical treatment center is often the way to go.

Disposing of Darkroom Chemicals at Home

Out of the three basic darkroom chemicals, you can only dispose of the developer and stop bath at home.

As the Film Photography Project states, one of the basic steps used to dispose of many darkroom chemicals is dilution. Dilution is the act of making a chemical weaker by mixing it with another substance, in this case, water.

The University of Florida’s Health and Safety Guidelines state that placing spent developer and stop bath in the same container will cause them to neutralize each other and lose their corrosive properties. This solution is then safe to flush down the toilet.

If developer or stop bath (used or unused) are being disposed of separately, then you will just need to dilute them and flush them down the toilet.

Disposing of Darkroom Chemicals at a Treatment Center

You will be able to dispose of the developer and stop bath at home or at a waste treatment center. Fixer, on the other hand, contains a high silver content. This means you can only dispose of it at waste treatment centers or similar facilities.

As Lincoln University’s Health and Safety Guidelines state, to dispose of spent fixers, you’ll first have to remove the silver in the fixer. You can do this by pouring the fixer into a bucket and placing a steel wool pad inside it.

In around a week, the steel wool pad will have collected the silver from the fixer. The silver will have a sludge-like consistency that will make it easy to distinguish and remove from the liquid fixer.

After removing the solid silver sludge from the mixture, the leftover liquid fixer solution is now safe to dilute and flush down the toilet.

Disposing of the steel wool pad and the silver sludge at home won’t be possible without special equipment. Instead, you can take them to a local household hazardous waste facility. The government handles waste disposal at these facilities and it is usually free.

Check out the “Finding a Waste Treatment Center Nearby” section to find out where and how you can dispose of your darkroom chemicals in a waste treatment center.

How Businesses can Dispose of Darkroom Chemicals

Disposing of darkroom chemicals for free is usually only an option for hobbyists. Businesses such as print shops will be using darkroom chemicals in much higher quantities, so their only option is professional waste disposal.

However, just like it is for hobbyists, businesses will also need to remove the silver from their fixer before disposing of it.

Businesses will be using fixer in much higher quantities, so a steel wool pad will not be able to remove all the silver from the fixer.

Instead, businesses will have to use a silver recovery device. These are devices that separate silver from fixer so the liquid fixer is safe to dispose of.

These devices use an electric current to separate the silver from the fixer and come with a tray for storing the silver sludge apart from the liquid fixer.

You can reuse these devices until a sufficient amount of silver sludge has built up in the tray, at which point you can collect the silver sludge and take it to a silver refinery or dispose of it separately at a waste treatment center.

Silver refineries will happily accept this silver sludge at no cost. Trying to sell the silver sludge to refineries is also an option, but is not likely to return much profit due to the cost of refining the sludge.

Now that you have removed the silver from your fixer, you can dispose of your developer, stop bath, and fixer.

One option for businesses is to contact their local waste treatment center and propose an agreement on the treatment of their waste darkroom chemicals.

Due to the high volume of chemicals professional print shops or other such businesses produce, they will most likely have to pay a fee to dispose of their chemical waste at a government-operated facility.

The second option for these businesses is to hire a private waste disposal company.

Private waste disposal companies offer curbside pickup for businesses, so all you’ll need to do is leave out your darkroom chemicals in labeled containers.

They will then pick up these containers and dispose of them, much like how curbside garbage or recycling disposal works.

The third option for such businesses is to contact local landfills and find one that will accept darkroom chemicals.

You can then take your darkroom chemicals to the landfill and dispose of them yourself.

Finding a Waste Treatment Center Nearby

Waste treatment centers are very useful since they make disposing of darkroom chemicals safe, easy, and inexpensive (if not free).

In the US, you will be able to dispose of your darkroom chemicals in Publicly Owned Treatment Works (POTWs), landfills, and other waste disposal sites. 

You can find your local waste disposal site by searching up “Environmental Protection Agency household hazardous waste” followed by the name of your state.

This will bring up the Environmental Protection Agency’s (EPA) designated website, where you will be able to find waste disposal sites near you.

For example, the Illinois EPA website lists the disposal guidelines in that state, and also includes a map to search for any waste disposal sites in Illinois. 

Final Thoughts

Disposing of your darkroom chemicals might sound like a daunting task, but it is much simpler than it sounds.

Now that you’re armed with the knowledge of the proper ways to dispose of your darkroom chemicals—and able to keep yourself and those around you safe from the hazards that come with these chemicals—you’ll be able to develop your photographs in peace.

Other articles you may also like: