What’s the difference between pigment-based and dye-based?

The Science of Art By Mot Tuman:

Mot explains the various characteristics of dyes and their origins and uses and the some unique differences between them in this article with a full video

You might have heard people talk about whether an art supply is pigment based or dye based, but what does that really mean?

Dyes and pigments are both known as colorants, which is essentially anything that gives color to something else. But the difference between dyes and pigments is that dyes are water soluble, whereas pigments are not.

For example, take two jars and add water, now take the dye put into one jar, and then a little pigment and pour into another jar. What you will be able to tell as soon as they are added to the water filled jar is that the dye starts to dissolve and create a solution, and pigments will tend to sit on top of the water and never really fully mixes or combines with the water. (pigment needs to be stirred a lot)

One of the other biggest known differences between dyes and pigments

Besides the water solubility is their differences in lightfastness. Dyes are known for being less lightfast and pigments are more lightfast. One of the reasons that is the case is because their molecular structure is completely different.
QUICK Info: The term “lightfastness” pertains, to how a substance, like a pigment or dye found in paints inks or similar colored items can withstand exposure without fading or altering its color over a period of time.
See referenced pigments: Dry Pigments

Breaking down the science of Dyes vs. Pigments – The Molecular Structure

To visualize a representation, we used use a balloon and a piece of paper as a very simplified example of what the different molecular structures of a pigment versus a dye looks like.

This right here is our pigment molecular structure

Imagine all of these circles drawn on here are individual molecules. They like to take the form of a particle, a rounded shape, as opposed to a dye. This piece of paper is our dye, and all of these circles are, again, it’s molecules. It likes to take a much flatter, larger surface area than our particles for our pigments typically would. This structural difference is the reason that dyes are so much less lightfast than pigments are.

You can imagine when UV light is coming down and hitting this pigment particle, it’s really only going to be hitting one side of it.

All of the molecules that are inside this pigment particle or on the opposite side of it aren’t going to be hit with direct UV light as opposed to a dye, which since it has such a large, flat surface area, is going to be hit with the full blunt force of UV light, making it a lot more fragile when exposed to light.

Even though the molecular differences between a dye and a pigment make it so that dyes are less lightfast, it also makes it so dyes are a lot more vibrant than pigments

We’re only seeing one little side of this pigment, so we’re only seeing a tiny bit of its color potential, whereas with our dye, we’re seeing all of the molecules at once, allowing our eyes to pick up on a lot more of the color!

There’s lots of different fun stuff we can do with dyes, but one of the really exciting things that you can accomplish with dyes that you can’t get with pigments is fluorescent paints

Fluorescent pigments do exist, but they’re actually just modified dyes!

What they do is they take dye and they dissolve it in a plastic or a resin, and they let that dry and grind it up into a super fine powder so that you can get fluorescent paint, just like these Soho Fluorescent Acrylics.

Unfortunately, since these paints are dye -based, they are still not lightfast, but we really can’t get this vibrancy without them being fugitive. So it’s kind of a trade -off.

One of the other fun things that you can do with dyes that you can’t really do with pigments is alcohol markers

We got our Artfinity markers here, some papers and some alcohol inks. Alcohol ink works as a great medium for carrying dye because it dries really rapidly, leaving only the dye behind.

Since dyes form an actual solution with alcohol, instead of just sitting in it like a pigment would, it can create really smooth, crisp washes of color.

That coupled with its super fast drying time is what allows it to create such clean, crisp, smooth gradients.

One of the other things that makes dye work so well with alcohol is that alcohol is a much weaker surface tension than water does, which means if I pour out this alcohol ink on to the paper you can see how quickly it disperses and spreads out and gets that really nice flowy effect that a water-based product wouldn’t get.

See referenced dye-based supplies: Artfinity® Sketch Markers & Sets, Artfinity® Alcohol Inks

For comparison, this is another dye solution that’s water-based instead of alcohol-based. You can see just how much it kind of likes to hold together because it has such a stronger surface tension than the alcohol does.

While dye-based products don’t have the same level of lightfastness as pigment-based products do, they have other traits that really can’t be matched by pigments. Their level of vibrancy and solubility are things that pigments can’t replicate.

Some Questions and Answers

What is the difference between pigment and dye-based inks?

A: The main difference between pigment based and dye based inks is centered around the coloring agents they employ and their interaction, with the surface on which they are applied. Dye-based inks are more saturated and vivid colors, as they have a low diffusion factor.

What are the disadvantages of dye inks?

A: Dye-based inks although more vibrant are not as lightfast as pigments. They tend to not be as durable and can fade when exposed to light and are less desired for archival use.

Are dye inks permanent?

A: Dye-based inks produce vivid, vibrant colors but they are not permanent like pigment based inks. Due to the molecular structure of dye-based inks they are known for being less lightfast and can fade over time from light exposure.