Darkroom Chemicals: Everything You Need to Know

In a darkroom, the chemicals you use and how you use them could make the difference between a good photo and a great one. Shooting on film and developing your own images gives you control and your pictures gain a depth and feel that does not come across on a digital image. When starting out with developing your own film and making prints in the darkroom, you may have questions about the overall process – especially about the chemicals involved. Keep reading to find out all you need to know about the chemicals used in the photographic darkroom.

Today, setting up a darkroom in your home is a possibility and pretty simple. Whether you are developing your own film or just making prints from existing negatives, the process for developing the light-sensitive materials, paper or film, is basically the same. 

What Three Chemicals Are Used in the Darkroom?

The three chemicals used in the darkroom are the developer, stop bath, and fixer. These three darkroom chemicals do the following:

  • A developer makes the pictures appear
  • A stop bath stops the developing process
  • The fixer rinses away any excess chemicals and “fixes” the film so it isn’t light sensitive any longer.

Developer: Starting the Process

A developer reacts with the silver halides, making a picture appear. For black and white film, you use black and white developer. For color film, you need to use a different developer for C-41 chromogenic color print film. C41 is the most common type of color film and contains dyes to bring out the different hues.

Stopbath: Stopping the Process

A developer will keep developing unless you stop it. If you wait too long, your film or print will be over-developed. A stop bath stops the developing process by neutralizing the developer. Because stop bath is acidic, it has a strong vinegar-like smell.

Fixer: Finalizing the Process

Once the stop bath has done its job, you want to stabilize the process. Fixer rinses away any leftover silver halide as well as the other darkroom chemicals so you can safely expose the film or print to light.

Black and White Developers 

For black and white processing, some suggested darkroom chemicals for developing are:

  • Kodak D-76 – A powder, this developer is an oldie but goodie. D76 was originally made by Kodak in 1927. This is one of the most popular developers.
  • Ilford ID-11 – This powder developer is essentially the same as the D76 with some minor differences. Both Ilford ID-11 and Kodak D-76 are considered standards for developers.
  • Kodak XTOL – A two powder developer, Kodak XTOL is known for its ability to handle fine grain and provide high sharpness. 
  • Adox Adonal or Rodinal – This liquid has a reputation for fine grain and high sharpness. This is highly concentrated and can only be used once and cannot be reused. Unlike most liquid darkroom chemicals, it has a very long shelf-life.
  • PMK Pyro – PMK stands for Pyro-Metol-Kodalk. Available in liquid form and manufactured by Kodak, it gives you consistent results with high sharpness. Its staining ability gives you a broad tonal scale and that rivals any others. 

I recommend the Kodak system of developing chemicals. See this article for how to use it to develop black & white film at home.

There are so many choices in developers, and these are just a few. You may need to sacrifice some film to test while you experiment to discover which are the best darkroom chemicals for your darkroom.

Monobath Combines The Three Chemicals Into One

 Monobath (Mono meaning one) is a solution that combines all three darkroom chemicals into one used for developing black & white film. By blending all three into one single liquid, you can significantly shorten the time for processing film as well as save money. There are two common monobath brands available:

In my experience, monobaths are reusable, have a short shelf life (around 2 months once opened), and you need to be very precise with the timing and temperature when developing your specific kind and ISO of film, especially after each developed roll. Others have recommended agitating the film in the development tank for a few seconds longer than suggested to avoid bromide drag on the negatives.

C41 Processing Kits Contains What You Need For Color Film

If you are working with color film, you will need a C41 kit. These kits contain developer, bleach, and stabilizer specifically made for color film. Some are in liquid form while others come in powder form. There are several companies that sell C41 kits including:

I recommend the Ultrafine Unicolor C-41 kit from the above list. See this article for how to use it to develop color film at home.

Other Darkroom Chemicals

The three basic darkroom chemicals of developer, stop bath, and fixer are fundamentally all the darkroom chemicals you will need to get started developing and processing your own film and prints. However, there are other darkroom chemicals that can simplify the process, make the process more efficient, or enhance the process.

Photo-flo Creates Streak-Free Photos

Photo-flo is a Kodak product used to reduce water spots and streaking when you are developing film. It may not be essential to have in your darkroom chemical collection, but it will help keep your film negatives from having water stains and marks especially if you live in an area with hard water.

Washing Aid / Hypo-Clear Reduces Washing Times

A washing aid like Ilford Washing Aid or Kodak Hypo-Clear is a solution that significantly lowers the washing times both film and darkroom paper. This solution is more commonly used with fiber-based darkroom paper and reduces the washing time from several days to 30 minutes. Keep in mind that both brands can be used with either brand’s developing chemicals.

Bleach and Fixer Makes Blix For Color Film

A bleach and fixer combination, Blix is used to remove the final layer of chemicals on color film. This last chemical rinse finalizes the process and stabilizes the image so after this step it is not sensitive to light.

Clean up With Photo Emulsion Cleaner

Photo Emulsion Cleaner or PEC cleans up your photos by removing almost anything that has made its way onto them and is carcinogen-free. it can remove the following things from your negatives:

  • Fingerprints & finger oils
  • Mildew
  • Smoke residue
  • Ball point Ink  
  • Tape residue
  • Wax
  • Permanent Ink

Photo Emulsion Cleaner is a good idea to have around for accidents, even if it is not part of the developing process.

Hypo-Check To Check Fixer

Since darkroom fixer can be reused you need a surefire way to test the strength of your film and paper fixer. A Hypo-Check solution does this for you. To test your fixer, pour a small amount of your fixer into a smaller, separate container and drop 1-2 drops of Hypo-Check into it. While the Hypo-Check won’t harm your fixer if it is still good to use, putting a small amount into another container makes it easier to see the results.

If the fixer remains the same then is it ok to use and nothing has been done to the solution so you can pour it back into the rest of the fixer. If the fixer becomes cloudy, then all of the fixer is exhausted and shouldn’t be used. A 3/4 oz. bottle of Hypo-Check provides around 800 tests and does not go bad so it will last a long time.

Eco-Friendly & Low Toxicity Darkroom Chemicals

It is possible that you want more eco-friendly and low toxicity options for darkroom chemicals for developing film or but you still want them to be effective. If this is true for you, then I recommend the LegacyPro EcoPro line of darkroom chemicals. There chemicals are:

  • Virtually Odorless
  • free of known carcinogens and mutagens
  • free of Metol, hydroquinone, borates, and phosphates
  • free of non-biodegradable organic compounds: EDTA and DTPA
  • Free of acetic acid, perfume, and dye
  • Designed to minimize chemical wastage
  • Still is Archival
  • Has an extended tray and shelf life
  • The EcoPro fixer can be used with both a water bath or stop bath. However, when used with a water bath the fixing time is cut in half.

LegacyPro EcoPro darkroom chemicals come in formulations for both black and white film and darkroom paper. You can find some of the EcoPro line on amazon.com and but the website freestylephoto.biz has more options to choose from.

See this article on how to use LegacyPro EcoPro fixer when developing black & white film at home.

The Dangers of Darkroom Chemicals FAQ

Most hobbyists consider the chemicals they use to be very safe. And generally speaking, darkroom chemicals when mixed and used properly are not toxic. The problem is that some home darkroom enthusiasts are not trained on the proper use and handling of darkroom chemicals. That could lack of understanding could make the difference between a safe hobby and a dangerous one.

There are always dangers when using any type of chemicals. Always use caution when working with darkroom chemicals. Let’s take a look at some facts about the dangers of darkroom chemicals.

  • The dry, concentrated form of most darkroom chemicals can cause problems if inhaled when mixing
  • Some people are sensitive to powders and may have breathing problems if they breathe them in while mixing them so be sure to mix them in an area with plenty of ventilation, like outside and never in an enclosed area like a photography darkroom.
  • Some darkroom chemicals such as toners, release toxic fumes while processing. Always make sure your darkroom is adequately ventilated and you have access to fresh air.
  • Darkroom chemicals are irritants. If you touch them with your bare hands, some darkroom chemicals can cause contact dermatitis or you can build up an allergy to them over time.
  • If you get darkroom chemicals in your eyes, immediately flush with water and get help. Darkroom chemicals are irritants and could become a problem after repeated exposure to your eyes.
  • Darkroom chemicals are not flammable.
  • There is no consistent proof that darkroom chemicals can cause cancer.
  • If you are pregnant, you should always use precautions in anything you do. Working in a darkroom is no exception. Although there does not seem to be any problems with pregnant women working with the chemicals used in a darkroom, if you have any concerns you should check with the manufacturer. 
  • Color darkroom chemicals are more toxic than black & white chemicals for you and the environment so always take precautions like wearing gloves, an apron, protective eyewear, and a mask when using color development chemistry – especially when mixing and using the open tray method of development.

Powder Versus Liquid Darkroom Chemicals

Darkroom chemicals come in either a powder or liquid form and some only come in one form. Which is best is open for debate and is really up to you, what you prefer, and what is available.

The powder form is generally less expensive, best for shipping, and has a longer shelf life even when opened. However, the powder form is harder to mix correctly because of precise water temperatures and you want to avoid the possibility of inhaling the powder when mixing.

On the other hand, liquid darkroom chemicals are generally more expensive, harder to ship, have a much shorter shelf life before and after mixing, but they are much easier to mix. Also, liquid chemicals come in concentrate so they can be mixed in smaller batches, which means you won’t use as much or waste as much. 

One thing to note is it is almost impossible to get all powder version of darkroom chemicals. For example, to my knowledge Kodak doesn’t offer a powered version of their stop bath. On the other hand, Ilford mostly only offers liquid versions of their darkroom chemicals.

Powder Darkroom Chemicals

A list of popular and reliable powder darkroom chemicals for color and B&W film and paper:

Made By Kodak

Made by Ilford

Other Brands

Liquid Darkroom Chemicals

A list of popular and reliable liquid darkroom chemicals for color and B&W film and paper:

Made By Kodak

Made by Ilford

Other Brands

While powder darkroom chemicals are fine, it is suggested that beginners start with liquid darkroom chemicals until they are more experienced because of liquid being easier to mix.

How to Mix Powder Darkroom Chemicals?

When mixing powder chemicals for film development, you need to use the recommended water temperature, and it’s best to always use distilled water rather than tap water, which can leave mineral deposits on your photos depending on the water quality where you live.

Always mix darkroom chemicals (especially powder versions) in a well-ventilated area like outside (the chemicals are in concentrated amounts but not light sensitive). I recommend putting on an apron, gloves, and eye-protection when mixing both powder and liquid forms.

Pour the 3 liters / 3 quarts (or roughly 3/4 of the water for the intended amount) of distilled water into the storage bottle first, using a funnel.

Then pour the packet of developer powder in the distilled water. Stir the solution rapidly with agitation until it is completely dissolved.

Pour in the rest of the water and mix until dissolved.

Kodak D-76 at full strength it is recommended to mix the solution at 1:1. This means a gallon of water for the amount in the packet. If you wanted to make half of the solution then use half a gallon of water and half of the packet of powder. The same steps apply to powder fixer as well unless otherwise noted on the directions, however, some fixers like Kodak Rapid Fixer has two parts needed to be added together. However much you decided to make, always follow the directions on the package.

How to Mix Liquid Darkroom Chemicals?

When mixing liquid developers, stop bath, or fixers (or other darkroom chemicals) the process is similar but you are using liquid instead of powder.

For example, Kodak Stop Bath should be diluted with distilled water at 1:63. This means for every part of stop bath it should be mixed with 63 parts water. I recommend thinking of it this way. If you want to make a gallon of stop bath, 1/63 of a gallon is 2 US fluid oz. so for 1 gallon of water, you will need 2 US fluid oz. of stop bath. Make sure to properly mix it together before using it. Again, however much you decided to make, always follow the directions on the package.

NOTE: Be aware that each type of darkroom chemicals will need to be mixed at a specific temperature. For example, based on the instructions, Kodak D-76 developer should be mixed between 122 – 131 degrees Fahrenheit (50 – 55 degrees Celsius). This higher temperatures ensures the powder will fully dissolve. Again, always follow the directions on the package.

Keep track of the temperature of your processing solutions using a stainless steel thermometer like this one on Amazon.com.

How to Store Darkroom Chemicals

Storing your darkroom chemicals is actually easy. You can use special bottles designed for that purpose and can be dark glass or opaque plastic bottles. Many photographers use two-liter soda bottles as well and have no problems as long as they are kept in a cool, dark area.

You need to keep as much air out of your darkroom chemicals as possible in order to make them last longer. This may mean adding a few glass beads to a glass bottle to push out the excess air or purchasing special acordian-style bottles that pushes air out.

It is suggested that you use dark-colored or opaque storage containers to limit light contacting the chemicals although there is some debate with this. However, you decide to store your darkroom chemicals, make sure they are kept somewhere out of the way. You don’t want them to spill and cause a mess. You also don’t want children to get ahold of them. It is a good idea to clearly label all your darkroom chemicals for safety and your own convenience.

All darkroom chemicals should be kept in cool, but not cold, dry places and do not keep your chemicals in the fridge. It is also not a good idea to keep them in a humid place like a bathroom that is also being used.

If stored properly, some darkroom chemicals can last a long time. Some people have reported stop bath and fixers lasting years, sometimes decades. 

In general:

  • Mixed Developers can last up to six months if properly sealed.
  • Mixed stop baths can usually last for years. As long as the color is a straw yellow, you are good to go.
  • Mixed fixers are good for months as long as the pH stays the same. 

For specific details, refer to the manufacturer’s website. Also, most darkroom chemicals come with a data sheet with storage information.

Can You Reuse Darkroom Chemicals?

Some darkroom chemicals can be reused up to a point. It depends on the process you are using, the darkroom chemical, and how much the reused chemical affects your outcome. See the following tips for what chemicals you can reuse, but you should follow the manufacturer’s guidelines on your package for each chemical.

Color Darkroom Chemicals

Most color darkroom chemicals are one-shot, meaning they are meant to be used only once. For example, this Artista RA-4 color print processing kit on bhphotovideo.com is a one-time use product. However, there are other kits for processing color that can be used multiple times like this Tetenal RA-4 Color Paper Processing kit from freestylephoto.biz, which can do up to 200 8×10 prints.

Black And White Chemicals

Depending on whether you are developing film or making prints in the darkroom, whether or you not you can reuse the three chemicals used in the black and white process will change:

Film & Prints Developer

With film developer like Kodak D76, you do not want to reuse it since the developer will become exhausted after each use.

However, most developers used to develop prints in the darkroom can be reused as much as needed during a single session by pouring it back into the storage container after each use. Since you can actually see your print develop in the darkroom using a safelight when making a black and white print, you can see when the developer starts to slow down. Keep in mind, each time you reuse it, the strength of the developer weakens and requires a longer amount of time to develop your film or print.

Film & Prints Stop Bath

Stop bath can be reused again for both film and print development by pouring it back into the storage container after each use and can be reused until it has exhausted. If using a color indicator stop bath (like this Kodak Color Indicator Stop Bath from amazon.com) you will know when this happens because the color of the stop bath will change to a purplish-blue color.

Film & Prints Fixer

For both film and print development, you can use fixer again and again until it reaches its expiration by pouring it back into the storage container after each use. Remember though, each time you reuse it, the strength of the fixer weakens and it requires a longer amount of time to fix your film or print.

A good way to check the potency of your fixer is to use hypo-check (find it here on Amazon.com). Before using your fixer, pour some of the solution into a graduated cylinder and add 1 – 2 drops to the fixer. If it does nothing then your fixer is fine to keep using but if it turns a cloudy white, you have an excess of silver halide in your fixer and it should be disposed of properly before mixing a new batch.

How to Dispose of Darkroom Chemicals

Once your darkroom chemicals have reached the end of their life, it is tempting to just flush them down the sink. While darkroom chemicals used in a home darkroom do not impact the environment as much as a larger commercial facility, they can still cause some harm. Pouring them straight down the drain is not just a bad idea because it can be bad for the environment but in some cases, it can be illegal. Disposing of your spent darkroom chemicals in a way that has minimal impact on the environment can be easily managed without too much effort on your part. However, if you have a septic tank see the last paragraph.

Color Darkroom Chemicals

While it is possible to dilute color chemistry to make it safe enough to pour it down the drain, I recommend that you don’t take the chance and avoid pouring them down the drain altogether. Instead, I recommend collecting your color darkroom chemicals by pouring them into a disposable container like an empty milk jug once they are exhausted. After you have collected enough, dispose of them properly by transporting them to the nearest hazardous waste disposal facilities to you. An alternative to disposing of chemicals used in your darkroom is to take them to a photo lab, if you can find one, and ask them to dispose of them.

Black and White Darkroom Chemistry

In black and white darkroom chemistry, the purpose of stop bath is to neutralize the developer. Developer is an alkali and stop bath is an acid. Therefore, if you mix the two chemicals together, the result will be a neutralized solution that can safely be poured down the drain. To make sure all the chemical reaction has been neutralized, follow the mixture with first cold water, then hot water.

For black and white darkroom chemicals that contain silver such as fixers or toners, the silver in it needs to be recovered (or collected) and be delivered to a hazardous waste disposal site. To recover the silver, you can put the used chemical into a bucket with some steel wool. After about a week, the silver should be collected in the pad. You can then carefully pour out the rest followed by cold and then hot water. You can then take the steel wool or steel ball to the nearest disposal site when you are ready.

An Important Note If You Have A Septic Tank. The chemicals used in the darkroom could have a negative effect on the bacteria that live in your tank and keep it healthy (keeping your septic healthy is as easy as using a product like Rid-X once a month). To keep from damaging your septic system, I recommend collecting your darkroom chemicals and pouring them into a disposable container once they are exhausted and not pouring them down the drain. Once you have collected enough, dispose of them properly by transporting them to the nearest hazardous waste disposal facilities to you. An alternative to disposing of chemicals used in your darkroom is to take them to a photo lab, if you can find one, and ask them to dispose of them.

Darkroom Chemicals Safety Tips

Staying safe in the darkroom when you are using chemicals is important if you want to be successful in your hobby. Here are a few tips to keep you safe.

  • Keep the wet and dry chemicals away from each other.
  • Use color-coded trays to keep each chemical separate.
  • You should always wear gloves when developing prints in chemicals.
  • To avoid contact with any darkroom chemicals, you should always use tongs when handling the photo paper.
  • Make sure your darkroom is well-ventilated. This is especially important if you are mixing chemicals.
  • Always add acid to water. 
  • Always add water to the powder.
  • Label your darkroom chemicals.
  • Keep your darkroom neat. Put things back where you found them.
  • Don’t eat, drink, or smoke in the darkroom.
  • Have a spill kit nearby and know how to use it.
  • Use googles, an apron, and gloves to protect yourself when handling and mixing chemicals.
  • Once you have filled the processing trays with chemicals, don’t move them and risk spilling everything. 
  • If you have an accident, don’t hesitate to call for emergency help.
  • Keep your chemicals out of the way and not on the floor when using the darkroom.

Lee

My name is Lee and I love photography and learning. I received a Master of Fine Arts in Photography in 2010 and have worked as a university professor for the last 10 years in addition to being a working photographer. I started this website to learn more about digital and film-based photography and to provide a resource for all of my students.

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