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How to Dye Jeans Black – Complete Guide for Beginners

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A little bit of black dye can be a great way to change the style of your denim. Without disclosing too many embarrassing details, my own journey with dyeing black denim began in middle school, during a very intense but short-lived goth phase. My first black dye project was a pair of jeans – I used a box dye and it went absolutely terribly – but the good news is there are better tools, dyes, and resources available for dyeing now than there were 20 years ago! I also have a lot more experience now than I did then, so here are my tips for a successful denim dye bath.

man skating with black jeans on
Photo credit: Unsplash

Contents list:

Can you dye jeans black? And is it easy or hard to do?

Jeans can be dyed black and it’s a project that a beginner could take on. But remember to constantly agitate the fabric to ensure an even result, and balance existing colors if required. You’ll also need to set aside several hours and even leave your jeans in the dye bath overnight.

What’s the best way to dye jeans black?

My preferred method is to use fiber-reactive dyes as they’ll produce the most intense, colorfast, and reliable result, but they do require a few extra materials that you’ll need to order online. It’s not a dealbreaker, but if you’re on a tight timeline they may not be the best option. 

Box dyes are also an option. They’re more readily available, but more likely to fade quickly or not get as dark. I find box dyes more likely to bleed in the wash since they’re made from lots of different dyes, rather than only the dye you need for the fiber you’re dyeing – in this case, fiber-reactive dyes for cotton. Box dyes do contain fiber-reactive dyes, but they also contain the dyes needed for silk, wool, and other fibers which in this case would just be washed away. 

Finally, if you’re looking for a fun project, you could choose natural dyeing! Technically, walnut husks create a dark brown dye, but it looks very close to black, and if you’re starting with a blue denim the color will help balance the blue undertones. This process requires mordanting chemicals and buying specialist supplies and it’s definitely not a project you’ll be able to complete in a single day, but dyeing jeans with walnut husks is such a fun project.

With any method, the critical thing to remember when dyeing jeans is agitation. Denim is a densely woven fabric, so the dye is already going to have a harder time penetrating the fibers than it would with, say, a loosely woven silk. Additionally, denim gets quite stiff when it’s wet which makes it harder to manipulate the fabric to ensure the dye is absorbed evenly. Dyeing jeans with any method will require a period of constant babysitting – stirring and manipulating the fabric in the dye pot to ensure it’s absorbed evenly. Make sure you’re using a pot that’s large enough for the jeans to swim freely, and make sure you’re wearing comfortable standing shoes (or you have a cushy foam rug to stand on) – you’ll be stirring and agitating for between half an hour to an hour. After this critical first hour, you can stir occasionally, but constant agitation is key for an even dye bath in the first hour.

If your jeans have a percentage of stretch, like elastane or lycra, the process doesn’t change. These stretch elements are usually less than 5% of the garment, so they won’t make a visible difference. However, if your jeans are a poly/cotton blend that’s greater than 40% polyester, you may wish to explore polyester dyes (either iDye Poly or Rit Synthetic) or a disperse dye designed for polyester fabrics.

How to dye different colored jeans black

Most traditional denim is blue but occasionally you’ll find them in different colors. No matter what color your jeans are, the starting color will impact the finished product, even if only a little bit. Most dye instructions and recommended quantities assume you’re starting with a white fabric which will rarely be the case with jeans, so there are a few accommodations you may need to make for your project.

If your jeans are dark blue – the traditional denim color – they’ll likely have a bluish tinge to them even after you’ve dyed them. You can help combat this by adding orange to counteract the base blue. If they’re a more faded blue, this becomes less necessary but the choice is yours.

If your jeans were previously black and you’re getting them back to a shade as dark as night, it isn’t necessary to double the dye quantity – think of it as refilling a half-empty tank, rather than a completely empty one. You’ll still need to follow the full dye bath time and heat instructions though.

For lighter greys and white, nothing changes – just follow the instructions as they’re written below for your chosen method. 

Precautions to take before you start dyeing:

  • Cover your countertops with a sheet of plastic and old newspaper. The plastic will keep everything contained, and the newspaper will absorb anything that does happen to spill. You can wipe the plastic clean and reuse it next time.
  • Immediately wipe up any spilled dye powder before it has a chance to become airborne or land on something it might stain.
  • Protect your hands with long kitchen gloves. You can use surgical gloves in a pinch, but they’re not as long so you might get dye on your forearms. I also suggest an apron to protect your clothes.
  • When you’re agitating dye baths, try to vary your mixing methods to get an even result. Use tongs and carefully tease apart layers of fabric that are pinched or stuck together. Keep pushing any fabric that floats to the surface back down. 
  • Consider ‘overdye’. If you want to achieve colors with some fun textures and depth, try creating, say, a purple by dyeing your fabric red first and then blue. This often yields different results than mixing blue and red together and it can be gorgeous.
  • Write everything down! At a minimum, record the weight of your fabric, weight of dye, weight of fixative/mordant, and the amount of water you used. You can also record the temperature of the dye bath and the length of time it spent in the dye. You never know when you’ll come up with the perfect dye recipe that you’re just *dyeing* to recreate!

Related: Will Fabric Dye Stain my Pot, Sink or Bathtub? & How to Fix

How to dye jeans black using fiber-reactive dyes (the best method)

Most denim is cotton – either 100% or about 95% with some elastane added – which means that fiber-reactive dyes will work best. Fiber-reactive dyes are specifically designed to work with cotton, and they chemically bond with the fibers to create a long-lasting color. When dyeing blacks, the stovetop method is preferred since the heat helps set the color. This is a bit weird, since fiber-reactive dyes don’t usually require a stovetop, but black is an exception.

Supplies:

  • Fiber-reactive dye in a desired shade of black.
  • Dye activator: Salt and Soda Ash.
  • A dye pot made from a non-reactive metal like aluminum.
  • Rubber gloves.
  • A set of teaspoons that you’re not going to use for any food in the future.
  • Dust mask.
  • A small plastic cup and stirring stick (I like a plastic knife) to mix the dye solution.
  • Tongs, a stirring spoon, or something similar to stir your dye bath.
  • Optional: Kitchen scale (gram increments) and mini scale (hundredths of gram increments) and a thermometer.

Step 1: Pre-wash your jeans

Pre-wash your jeans in hot water and treat any stains. Don’t worry about drying them.

Step 2: Measure the dye

You can follow the packet instructions to measure out how much dye you need for the weight of your jeans – it’s usually about 6% of the weight of the dry goods – but since we’re going for black and the exact shade matters less, you can also go rogue and just estimate with a tablespoon of dye powder.

Step 3: Mix the dye

Make sure you put a dust mask on before you open the jar of dye. Most powder dyes are lung irritants.

Place your dye into the plastic cup, and add hot (but not boiling) water gradually, mixing until it becomes a paste and then a liquid. You can strain this liquid through muslin if any granules of dye are left undissolved. Once the dye is dissolved and the lid is back on your jar, it’s safe to remove the dust mask.

Step 4: Add jeans and water to the dye pot, and turn up the heat

Add the damp jeans to the dye pot, along with enough water for them to swim freely, but not so much that the pot overflows. Heat the water to 54-60 degrees celsius (130-150 Fahrenheit) 

Step 5: Add the soda ash, salt, and dye

Add 6-18 tablespoons of salt per 450g of fabric, and 3-9 tablespoons of soda ash. This is twice as much as you’d normally use since we’re dyeing black!

Shuffle your fabric to the side with your tongs or spoon so you’re not pouring directly on the fabric. Mix thoroughly.

After this has dissolved, add the cup of pre-mixed dye in the same way – pushing the jeans to the side to avoid pouring on them directly. This helps to avoid dark splotches. Mix thoroughly. You can swish a bit of extra hot water in your dye cup and add it to your dye bath to make sure you get it all.

Step 6: Stir frequently until the dye is absorbed. Turn off the heat.

Maintain the temperature and stir frequently until the dye is absorbed. You’ll want to pay extra attention to the dye bath (agitating constantly and monitoring the temperature) for the first hour, but after that you can taper off, turning down the heat and stirring less frequently for a few hours. You can turn off the heat and allow it to sit overnight if required. Jeans are quite a mission to stir when they’re wet – the fabric gets stiff and tends to crease, so be sure to pay extra attention to ‘spreading out’ the jeans in the water and making sure they’re submerged.

Step 7: Remove your jeans from the pot and rinse 

Remove the jeans from the dye bath after it has cooled down. Rinse under hot water and then cool water. Wash with a bit of hand soap and make sure the water runs clear. This will take what seems like forever with black, but don’t stop until the water is completely clear! This is the key to making sure the dye doesn’t bleed in the future.

Step 8: Machine wash

Depending on your fabric, you may wish to follow the in-sink rinse with a run through the washing machine, or even just pop it in for a spin cycle.

How to dye jeans black using box dyes like Rit or Dylon:

A quick disclaimer before we begin: I generally find box dyes to yield a less consistent result, and to have a greater chance of washing out and staining other things in my laundry, so I tend to avoid them. That said, sometimes they really are the best option – especially if you’re not willing to go for a whole dye setup in your house, so here are some tips for working with black Rit and Dylon.

Rit recommends using twice the usual recommended amount of dye for the weight of your fabric, and doubling the recommended time it spends in the dye bath, as well as using the post-dye Color-Stay Dye Fixative.

Supplies: 

  • Black box dye of choice
  • Rit Color-Stay Dye Fixative (if using Rit dye)
  • Vinegar (for Rit or iDye) or Salt (for Dylon)
  • A dye pot that will not be used for food
  • Rubber gloves
  • Tongs, a stirring spoon, or something similar to stir your dye bath
  • A set of measuring spoons, but since you’re only using these for salt or vinegar, you don’t need a special “dye only” set – your regular kitchen ones are fine.
  • Optional: a kitchen scale to weigh your fabric.

1. Pre-wash and dry the jeans

Pre-wash your jeans using detergent. If they’ve been worn, use a stain treatment to lift any stains as these may cause your garment to dye unevenly. Let your jeans dry.

Step 2: Calculate how much dye you need

Once dry, follow the package instructions to estimate the amount of dye needed. Rit recommends one bottle for every 1-2 pounds of fabric normally, so double this for your jeans. Jeans usually weigh in at just under a pound, so two bottles should work.

Step 3: Add jeans and water to the dye pot

Add the jeans to your dye pot, fill it with enough hot water for them to swim freely, and turn up the heat to 60 degrees celsius (150 fahrenheit).

Step 4: Add the dye activator (salt or vinegar) and dye packet

Add 200ml vinegar (RIT) or 10 tablespoons of salt (Dylon) – per packet of dye. The dye activator is especially important when dyeing black.

Next add the dye, being careful not to pour directly on the fabric as this can cause dark spots.

Step 5: Stir frequently until the dye is absorbed

Stir constantly for the first half an hour, then frequently for at least 2 hours. After the first 20 minutes, you can turn the heat down. If you like, you can turn off the heat at the end of the two hours and allow the item to sit in the dye for several hours or overnight. 

Step 6: Soak in color fixative

Dylon does not specify a fixative, but if you’re using Rit – this critical step will lock in more of that vibrant black color. Remove your jeans from the dye bath, and add them to a fresh bucket of water with the required amount of Rit Color-Stay Dye Fixative (as per the bottle’s instructions) and allow it to sit for at least 20 minutes, stirring occasionally.

Step 7: Remove your jeans from the fixative soak and rinse

Rinse in hot water first, then cool water until it runs clear. Wash with a bit of hand soap to be sure all of the dye and fixative have been removed.

Finally, I’d recommend at least one run through your washing machine alone (without anything you’re worried about staining) to be sure all the dye has washed out.

How to dye jeans black in a washing machine

Before we begin, I do NOT recommend using black dye in a washing machine. Personally, I don’t dye anything in my washing machine because the risk of staining either the plastic parts of my machine – or subsequent loads of laundry – is too high for my comfort levels. Since most box dyes recommend at least doubling the amount of dye used when dyeing black garments, the risk of staining is also doubled. If you have a second washing machine you use for dyeing (don’t laugh! I know more than one person with a designated dye washing machine) – then by all means go for it, but I would strongly discourage you from dyeing anything black using the same washing machine you use for your laundry.

That said, the instructions for machine dyeing are really quite simple. iDye in particular comes in a dissolvable packet that you can add directly to your washing machine which means you don’t need to interact directly with any dye powder or liquid. 

Supplies

  • iDye – 2 packets for a black washing machine dye bath
  • 2 cups of salt (try to find non-iodised if you can, but this isn’t a deal breaker)
  • iDye color fixative
  • Optional: tongs or stirring implement (for a top-loader, just in case)

For a top-loading washing machine:

  1. Pre-wet (or pre-wash) your jeans before you begin. Drying them isn’t necessary, it helps if they’re damp when you add them to the dye bath.
  2. Fill your washing machine with as much hot water as you need for the jeans to swim freely (most likely a little less than half) – try not to overfill it, as this will dilute the dye.
  3. Add the dye packets, waiting at least a minute until the casing has completely dissolved. If you can’t get it to dissolve, you may need to fish the remainder out with a pair of tongs or a spoon.
  4. Once the dye is dissolved, add the salt and allow it to dissolve and mix thoroughly. You can agitate the washing machine to assist in the dissolving process.
  5. Add the jeans, being careful to spread them out as much as possible in the dye bath so they’re not scrunched up. Allow them to agitate for at least an hour, extending the dyeing time by resetting the agitation cycle before the rinse begins. The longer your jeans are in the dye, the deeper the resulting color will be.
  6. When you’re ready to finish the dye bath, allow the machine to run a rinse cycle, but add the iDye color fixative to this rinse once the tub has filled to help set the color.
  7. To finish, allow the jeans to run through an entire regular hot wash with detergent – then dry and you’re done!

For a front-loading washing machine:

  1. Pre-wet (or pre-wash) your jeans as you did above
  2. Add all ingredients – the dye and the salt, along with the jeans – to the washing machine at the beginning of the cycle.
  3. Set your machine to its hottest, longest wash. If there’s an eco setting available, you can use this as it will cycle the same water through the machine instead of draining and using fresh water, which will prolong the time your fabric is in the dye.
  4. When the dye bath has completed, you may wish to use the color fixative by running a quick-wash with the fixative in place of detergent.
  5. Whether or not you choose to use fixative, the final step is, as above, to run an entire regular hot wash with detergent to wash the excess dye out of your jeans.

How to dye jeans black naturally using walnut hulls

Natural dyeing is a fun option to explore, but it takes longer and requires specialist equipment and mordanting chemicals.

Supplies

  • Dye pot (stainless steel or enamel, not aluminum!)
  • Tongs or utensils to stir and manipulate jeans in the dye
  • Rubber gloves
  • pH test strips
  • Dyestuffs: Walnut hulls, or powdered walnut hulls from a natural dye supplier
  • Alum
  • Ferrous Sulfate crystals or iron water (see “modifier” below)
  1. Begin by preparing your walnut hulls – if you’ve purchased powdered hulls,  follow the instructions on the label. It will most likely need to be mixed with water, allowed to stand for half an hour, and then strained to remove any stray particles. Make sure your dye liquid is cool before you proceed to step 2. If you’ve harvested your own – boil the walnut hulls for half an hour, allow them to cool and sit overnight, and then strain them to remove the solids before using the liquids for your dye bath.
  2. Wash your jeans thoroughly in pH neutral washing liquid, paying special attention to stains. Even if your jeans are new, they should be washed to remove sizing or other finish chemicals from the fabric. You don’t need to dry them after this wash – they can go straight to the mordanting phase.

Mordant for plant fibers, a note: Generally, plant fibers are mordanted with a tannin followed by the dyestuff, but our walnut husks are already extremely tannin-rich, so we’re essentially mordanting and dyeing all at once! 

  1. To create your dye bath, add the extracted dye liquid from your walnut hulls to a pot, fill it with enough water for your fabric to swim freely, and add your jeans. Bring the temperature up to a simmer and maintain it for one hour, stirring occasionally.
  2. Turn the heat off, cover your dye pot, and leave it undisturbed overnight, for 12 to 24 hours. At this stage, it will be a moderate to dark brown. If it seems light, you can repeat the process with more walnut hulls.

4.5 –  in some cases, you may choose to post-mordent a plant fiber with Alum at this stage, especially if the color is not already a deep chocolate brown. Follow the process in steps 3-4, using 4 teaspoons of alum per 100g of fabric, and 1 1/2 teaspoons of washing soda (soda ash). This is not required in all instances, but useful if you’re not seeing the results you want. 

  1. To turn it black, we must add our iron modifier. Dissolve 1 1/2 teaspoons of ferrous sulfate per 100g of fabric in hot water, then dilute it with about a cup of cool water. Stir this mixture directly into your dye pot, being careful not to pour it directly on the garment. Allow it to sit for no longer than 30 minutes (prolonged exposure to iron mordant can deteriorate fibers).
  2. Remove your jeans from the pot, allow them to cool, and rinse thoroughly. Then wash with a pH neutral soap.

Will the new black color be permanent?

Depending on the dye method you’ve chosen, permanence may vary. If you’ve used fiber-reactive dyes and washed out the dye until the water runs clear, there’s very little chance that the dye will fade, but it’s definitely still worth washing your freshly dyed jeans separately from other clothes for the first few washes. All dyes will fade over time if the time frame is long enough, but using fiber-reactive dyes will yield the most permanent, colorfast result.

If you’ve used a box dye, I would *not* recommend washing your jeans with other, non-black articles of clothing. These dyes are much more likely to fade more quickly, especially if you’re washing your jeans in hot water. Treat them with care and you’ll certainly be able to extend the life of your jeans, but do keep an eye out for fading. 

Naturally dyed jeans will have the most varied results. In theory, the walnut dye should be quite permanent, but there are multiple factors at play here, including how fresh the factory dye bath was (these chemicals can impact the natural dye results), what kind of metal is used for the hardware, and whether the jeans have any stains – and that’s in addition to all the other things that can impact a natural dye bath, like the pH of your water and the material your dye pot is made from! Your mileage with your individual jeans may vary. For the best results, choose jeans that have been well-washed (in hot water with a scouring agent, if possible) and that are older and more worn-in because their previous dye treatment will have less of an impact on the natural dye this way.

How to set dye in black jeans so it doesn’t come out

If you’ve used fiber-reactive or natural dyes, you don’t need to follow any additional steps to make your dye colorfast. If you’ve chosen to use a box dye, a fixative can be helpful to help lock in some of those loose color molecules. Rit recommends their Color-Stay Dye Fixative which is by far the most popular version available, but iDye also makes their own version of a fixative which they recommend for use with their dyes. Both are used in very similar ways as a post-dye, pre-rinse wash, but be sure to follow the packet instructions for your specific project.

To keep your jeans as dark as possible for as long as possible, wash them as infrequently as possible in cold water, and line dry them. The heat from your dryer will cause them to fade faster, as will hot water. Store them out of direct sunlight and enjoy that black denim!

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This article was written by Kat Waters and edited by Sara Maker.

Kat Waters (author)
Kat has been sewing since her feet could reach the pedals, starting with quilts she made with her mom and eventually graduating to garments. She now makes everything she wears, occasionally teaches classes, and shares her projects on social media. Highlights include her wedding dress, shoemaking, and a love for almost any fabric that comes in hot pink! Read more…

Sources:

These sources were referenced in May 2022.