Though the terms “pigment” and “dye” are often used interchangeably in the art world, in truth, the two media are vastly different. Artists need to know what separates pigments from dyes when choosing the best way to represent their work.
Here, we’re going to go over the main differences between pigment vs dye and when to use each for the most dramatic effect.
What is a Pigment?
Pigment ink is a mixture known as a suspension. By combining finely ground particles with the appropriate vehicle, you can create colorful ink. As with other suspensions, if you allow a mixed pigment to sit untouched, the solids will eventually separate from the liquids and settle at the bottom of the container.
Historically, the dry component of a pigment contains natural materials such as charcoal, rocks, or minerals ground to a fine powder. Nowadays, however, you can also find synthetic pigments with bright, fade-resistant colors.
The vehicle, or medium, that you use will depend on the type of pigment powder you have and the effect you want. The vehicle keeps pigment particles together in suspension and acts as a binding agent to allow colors to adhere to surfaces such as paper or canvas.
Oil paints require an oil carrier, while acrylic paints need a specialized polymer emulsion. However, for applications such as watercolor, it’s better to use a waxier carrier such as gum arabic or gum shellac.
The Origin of Pigments
Some of the very first artwork known to humanity involved painting with pigments. Cave art dating back as far as 40,000 years uses red and black pigments to create images ranging from local wildlife to hand tracings.
The very first pigments contained readily available natural materials that would have been easy for early humans to gather. Manganese oxide from soil or charcoal from fire remains were popular black pigments, while iron oxides from clay and volcanic rocks formed most reds.
The ancient Egyptians began mass-producing pigments around 4,000 BCE. Their technology achieved a much wider variety of pure, bold colors than our early ancestors. One of Egypt’s most famous pigments was Egyptian Blue, later to be replaced by ground azurite and ultramarine.
Many pigment names are rooted in the color’s origin, some of which date back to the earliest periods of pigment-making. For example, the pigment color known as Umber originated from the rusty soils of the Umbria region of Italy. Charring this soil created a deeper, darker color still known to this day as Burnt Umber.
While you can still find all-natural pigments, they tend to be expensive and somewhat rare. Instead, most commercially made pigments get produced synthetically. Doing this allows for a virtually endless range of colors. You can also find pigments that are UV-stable, non-toxic, stain-resistant, and more.
When applying a pigment ink, it will lay on top of the base instead of bonding with it. With a medium such as paper, finer pigment particles may stain or soak into the paper. In general, however, the pigment forms a film on the surface of your substrate.
The vehicle is what holds pigmented ink to the base. Without a proper carrier, pigment ink may not stick to your paper or canvas. You also need to ensure that everything gets mixed well to avoid clumps or discoloration in your final piece.
What is a Dye?
While pigments and their vehicle form a separated suspension, dyes dissolve entirely to create a solution. Dyes are chemicals or solutes that can dissolve and bind to molecules in a solvent, much like salt or sugar dissolved in water.
If you let a dye sit, it won’t separate the same way a pigment ink would. Molecules will remain bonded to the solution, and so a true dye should remain an even color for the entirety of its shelf life.
While some dyes work in their unaltered form, many require a mordant for best results. A mordant is a material that allows a dye to bond and fix to a given substrate. Salts of metals such as chromium, iron, and copper all make excellent mordants, as do acids such as tannic or oleic acid.
The Origin of Dyes
As with pigments, humans have been using dyes for thousands of years. However, evidence of dye is slightly more recent, dating back to the Neolithic period. One of the oldest dyes known to man is indigo, made from the plant Indigofera tinctoria.
Dyes typically contained different natural materials than pigments. Instead of rocks and minerals, they most often included ingredients such as berries, roots, vegetables, and insects. Many required the use of a metal mordant such as aluminum, copper, or chrome.
It wasn’t until around the 1850s that natural dyes fell out of fashion. It became cheaper and easier to use synthetic dyes created in a lab. What’s more, synthetic dyes often hold their color better over time than delicate natural dyes.
Unlike pigments, dyes don’t just sit on their medium as a film. Instead, they chemically bind to their base, whether it’s paper, canvas, or textile. Dyes permanently alter the color of a substrate, some on their own and some with a mordant.
While dyes are just as easy to use as pigments, they can be much harder to maintain. Many are sensitive to UV light and will fade with exposure to sunlight, sometimes quite quickly. Some dyes are not soluble in water and may run or fade when wet.
When you plan on adding a splash of color to your piece, it’s essential to know whether to use pigment vs dye to get the effect you want. While pigment inks offer bold, long-lasting color, dyes bind to their base for truly permanent color.
You can find both pigment and dye-based media to transform any art project into a striking statement on color. Stamps, markers, and many types of paint come in pigmented and dye forms to give you plenty of versatility. Permanent solutions such as India ink or permanent markers are almost all dye-based.