Natural vs Synthetic Dyes: A Guide for the Eco-Conscious Crafter

There is a great dye debate among crafters and consumers alike. There are also many misconceptions about natural vs. synthetic dyes. What are the differences between natural and synthetic dyes? And which one should you choose?

Which one you choose will depend a lot on personal preference, the project you plan to use the yarn for, and the desired look.

Acid/synthetic dyes tend to have brighter, more consistent, and more lightfast colors, but can be harsher on the environment. Natural dyes are not as vibrant and can wash out more quickly, but are more eco-friendly and have unique color variations.

In this guide, we’ll break down synthetic vs. natural dyes and give you all the information you need to make educated decisions about which dye is right for you and your needs. 

Natural Vs Synthetic Dyes

Before we dive into all of the ins and outs, we need to define what we mean when we say natural dye or synthetic dye. 

Natural dyes are dyes derived from products found in nature. These can be plants, animals, and bugs. The dye process for natural dyes involves a mordant, which helps the natural dye to stick and stay fast to the fibers. 

Synthetic dyes, also called acid dyes, are dyes that are synthesized from man-made chemicals. These dyes are sometimes called acid dyes because the dye bath has to be acidic in order for it to work. This acid can be as easy as some common household vinegar. 

Each type of dye has its own set of pros and cons. We’ll go in-depth into each one further in this guide. But here is an easy reference table to give you the breakdown in case you need a quick answer. 

Natural Vs Synthetic Dyes Comparison Table

Although this table gives a great overview of natural vs acid dyes, there’s still a lot of information to learn. We’ll go in-depth into both natural dyes and synthetic dyes so you can see the reasons behind our table. 

Now, let’s get into the nitty-gritty of each type of dye, starting with natural dyes. 

The Complete Guide to Natural Dyes

In this section, we’ll talk about all things natural dyes. We’ll start with some examples of natural dyes and how they can be sourced. Then, we’ll move on to how the dye is extracted, what mordants are, and what role they play in natural dyeing. 

Lastly, we’ll go talk about the characteristics of natural dyes that make them unique from all other dyes and why people might prefer them over acid-dyed fibers. 

What are Natural Dyes?

Natural dyes are dyes derived from products found in nature. These can be plants, animals, and bugs. Here is a list of some commonly used natural dye products:

• Indigo (plant)

• Woad (plant)

• Madder Root

• Cochineal Insect

• Oak Tree Bark and Acorns

• Onion Skins

• Avocado Pits and Skins

• Goldenrod (flower)

• Cortinarius Mushrooms

This list is by no means all-inclusive; it’s simply to give you an idea of the types of things used for dyeing naturally. If you’re located in North America, here is a webpage from the USDA that has a list of native plants that can be used in natural dyeing and the color they produce.

As you can see, the types of things that can be used in natural dyeing are quite varied; some of them you can even get right from the grocery store! 

Check out this yarn we sell that is dyed completely with onion skins. I saved the skins of onions we used over a couple of weeks and then used them to produce this vibrant orange color. 

There are also a great many dye plants that you can find growing in the wild, depending on where you live. If you want to forage for your own natural dye stuff, make sure you check local laws about foraging and harvest responsibly to keep it sustainable.

Extracting Natural Dyes

Now that you have a handle on what types of things are used in dyeing, let's talk about how you actually get that color onto yarn or fabric.

The dye process for natural dyes is usually a much longer process than for acid dyes, sometimes taking from a few hours to a few days and even weeks. 

What makes it take so long, you ask? You first have to extract the dye from the dye products before you can use it. Extracting the dye is actually a fairly simple process; it just takes time.

To extract dye from most natural dye stuff, take whatever dye stuff you have and put it into a pot of clean water. Then you simply simmer the mixture for at least an hour. Sometimes simmering longer will result in a more concentrated dye bath, but that will vary by the product used. 

It’s important to never let the dye pot boil because this can turn some dye pots a brown color as opposed to the color they’re supposed to be. 

Because it takes so long to extract dye, natural dyed products are often more expensive than their synthetic dyed counterparts. However, you can also natural dye your own yarn using ingredients right from the grocery store, which would help decrease the costs. 

Once you have your dye extracted, you have to prepare the yarn or fabric to take the dye. This can sometimes involve something called a mordant. 

The Role of Mordants in Natural Dyeing

A mordant is a substance, commonly a mineral, that helps the color stick to natural fibers. The most common mordant is alum (Potassium Alum), which is also used in some food preservation, like pickling. 

A mordant works by ‘fixing’ the dye color onto the fiber by acting like a bridge between the dye and the fiber. This ensures that the color bonds to the fibers and helps them stay there longer. 

There are some dye products, such as tree barks, that naturally have a lot of tannins, which can act as a mordant. I didn’t use a mordant on the yarns I have dyed with Oak bark, Cherry bark, and Avocado pits and skins. Even without a mordant, you can still produce some vibrant colors. 

In order to mordant a fiber to dye with, you soak the yarn or fabric in a water/mordant mixture, sometimes overnight, depending on the mordant used. 

Natural Dye Characteristics

Not only is the natural dye process unique, but the colors and character you get from it are also unique. 

Natural dyeing produces colors that are not as consistent or ‘perfect’ as synthetic-based dyes. This color variation may not always be desirable, but it can create beautiful, unique effects that ensure no two items are completely alike. 

This variation can often be subtle, but it also adds depth to the color that is difficult to achieve with synthetic dyes. 

Another characteristic of natural dyed fibers is that they’re not as colorfast or lightfast as synthetic dyes. This means that the color could slowly fade over time or with frequent washings. 

Using a mordant in the dye process can help make colors stay longer, and there are certain dye products that stay longer than others.

In a world where everything is becoming mass-produced and ‘cookie-cutter’, using a natural dyed product can be a great way to move away from the fast-paced world and start towards slow living. 

The Complete Guide to Synthetic Dyes

Synthetic dyes, also called acid dyes, are dyes that are synthesized from man-made chemicals. These dyes are sometimes called acid dyes because the dye bath has to be acidic in order for it to work. This acid can be as easy as common household vinegar. 

How Do Synthetic/Acid Dyes Work?

Acid dyes have a negative charge and work by binding to the positively charged ions of the protein in animal fibers. In order for this to work effectively, heat has to be applied, and the dye bath has to be acidic. 

Because of the way acid dyes bind to proteins, they will only work on animal fibers, also known as protein fibers, such as wool, mohair, and silk. They won’t work on plant fibers, also known as cellulose fibers, like cotton or linen; other types of synthetic dyes work on cellulose fibers. 

Environmental Considerations of Acid Dyes

These dyes are pretty efficient in the amount of color they take up out of the dye bath. If the dyer does all the measurements correctly, all the dye should be on the fiber, and the dye bath should become ‘exhausted’. This means there is no color left in the pot, ensuring there’s no waste or extra dye that gets poured down the drain. 

Small-scale dyers are usually much more conscientious about ensuring the dye bath is exhausted; large commercial enterprises may not care as much. This means that buying from a small business can help ensure the environmental impact of synthetic dyes remains at a minimum. 

While a small-scale dyer might use household vinegar to make the dye bath acidic, larger operations could use a more harmful chemical, which could cause chemical runoff or excessive water usage. 

If this is something you’re concerned about, check out the webpage of the specific dye company to see their policies. 

Some people get skin irritation from synthetic dyes. If you have sensitive skin, it’s good to keep this in mind. 

You can test yarn by tying a small thread around your wrist and seeing if it irritates your skin. Washing a synthetically dyed yarn before working with it can also help remove any leftover dye from the dye process, which could be the cause of skin irritation. 

Getting yarn or fibers from places that are closer to where you live is an easy way to keep your environmental impact to a minimum. If that’s not an option, finding places that use recycled materials or leftover yarns from commercial weaving or knitting factories is a great idea.

At Flock and Forest, we use both natural dyed and commercially dyed yarns, but we try to make sure the products we purchase are supporting local businesses as much as possible. One of the places we get yarn to make our handtowels is a local fiber mill that sells old leftover cones of yarn. These seemingly small choices can make a big difference. 

If you love the science side and want to know more about the technical side of how synthetic dyes can impact the environment, here is a scholarly article that discusses environmental impact and ways the dye industry can become more environmentally friendly.

Synthetic Dye Characteristics

The colors created by synthetic dyes are capable of being much brighter and of a much higher variety than natural dyes. As well as bright colors, these dyes can last much longer than natural dyes, even after frequent washings. 

Synthetic dyes are also more consistent as long as the dye process is carried out effectively. Because acid dyes are so consistent, there are even some dye processes for acid dyes that try to mimic the subtle variation of natural dyes.  

This type of dye can have the tendency to bleed before it’s washed, which is why you should always wash this yarn separately until the water is clear before washing it with other garments.

If you use the same formula over and over, you can get the same result nearly every time. This makes acid dyes more desirable for large-scale, commercial enterprises. This mass production makes these dyes cheaper and more affordable.

Should You Choose Natural or Synthetic Dyed Yarn? 

Now that you’re armed with all that knowledge about synthetic vs natural dyes, let’s break down which one you should choose. 

Which you choose is going to depend on a lot of factors: the project type, budget, personal environmental philosophy, allergy considerations, desired color, and color characteristics. 

Check out this easy table to get an easy look at which type of yarn is best for each type of project.

Natural vs. Synthetic Dye Project Comparison Table

We’ve covered a lot of ground here. I hope that all this information was helpful! You can now go out and make the best choice between natural and synthetic dyes.

If you want to see some of the possibilities of natural dyed yarn, check out the colors we offer here.