Watercolor Paint 101

This post was formerly titled “Supplies Deep Dive: Watercolor Paint, How Does That Work?” I renamed it to be in line with similar posts: Watercolor Paper 101, Watercolor Brushes 101.

After painting for awhile, I’ve come to decide that the most crucial make-or-break supply to whether you will have a good time is the paper. But paint? Paint is more fun.

Properties of Watercolor Paint

Properties inherent to watercolor

Watercolor paint is made from pigments suspended in a translucent water-soluble binder, usually gum arabic. Other types of paint, including oils and acrylics, will often use the same traditional pigments, but in different binders. It’s the binder that gives watercolor its unique properties:

• Translucent (you can see the white of the paper through the paint)
• Water-soluble (can be thinned with plain water)
• Dries hard but can be re-wet on a nonporous mixing surface (e.g. ceramic, metal, plastic)
• Adheres to paper and becomes permanent once dry on paper

These are properties that all watercolor paints, for the most part, share.

There are also properties that can differ from paint to paint.

Paint Options

These are some choices you make when you choose between different paints.

Format

Brand

The manufacturer of the paint. Some common artist grade brands (and the abbreviations I usually use for them):

• DS – Daniel Smith
• DV – Da Vinci
• HO – Holbein
• SH – Schmincke Horadam
• WN – Winsor & Newton

Those are the biggies for me, though on this blog, we’ve also been known to refer to other brands such as Daler Rowney, M. Graham, MaimeriBlu, Mijello Mission Gold, Qor, Rembrandt, Roman Szmal, Rosa Gallery.

Read about brand differences in Hanna’s guest post, Watercolor Brand Differences, or my post, What’s the best artist-grade paint brand for beginners?

If you’re comparing notes about paints with others, it’s useful to include the brand as the color name alone may not be enough information. The same color name across different brands may mean different things.

Grade (Quality)

Some reputable student grade brands are Winsor & Newton Cotman, Van Gogh, Schmincke Akademie, and Daler-Rowney Aquafine.

I explored student grade paint in the posts 20 Student Grade Winsor Newton Cotman Watercolors Compared to Professional Grade and Van Gogh Dot Cards!

Color

Paint Stats

Here I’ll get into the more nitty-gritty technical details of various paints and pigments. You might see information about these qualities on the label of the paint itself, or in paint catalogues/websites.

Pigment(s) used

Every paint uses one or more pigments. Pigments are natural or lab-made substances that are used to give paints their color.

To find out what pigments are used, look at the color index codes, or pigment codes, on the ingredients list of the paint. For example, “PB29” (pigment blue #29) refers to ultramarine blue; “PY97” (pigment yellow #97) refers to Hansa Yellow Medium.

Number of Pigments in a Paint

Paints made from just one pigment are often preferred by artists who like to mix their own combos, while those made from two or more pigments may be referred to as “convenience mixes.”

Pigment Families

Pigments are sometimes discussed as being part of “families” based on their chemical structure and the way they are made. These can also be broken down into synthetic vs. natural (lab-made vs mined), and/or into organic vs. inorganic (in the chemistry sense: organic pigments contain carbon, inorganic do not). For more info (and my subjective opinion!), see Rating the Watercolor Pigment Families.

Color Variation Within a Single Pigment Code

Most pigments have a fairly consistent color across brands and preparations, but some may be expressed in a variety of different hues. For example:

• Iron oxides such as PR101/PR102 and PBr6/PBr7 may create a range of browns
• The quinacridone pigment PV19 may be used to make a rose-to-red shade or a violet shade
• Cadmiums create a range of shades; e.g. the cadmium yellow pigment PY35 makes a range of shades of yellow from lemon to deep orange-yellow
• The cobalt pigment PB28 may be blue or turquoise

Pigment code alone may not be enough to know what exact color the paint is, but it can give you a good idea of the possible hue range and of some other properties.

Relationships Between Pigment Code and Paint Color Name

Note that the paint color name may or may not correspond to the pigment(s) used. Paint color names are not standardized. The same pigment may be referred to with different names by different companies. Or, the same name across different companies may be made with different pigments. That’s why it’s so important to look at the pigment codes.

Toxicity

Watercolor is a pretty safe medium, but some pigments are toxic if ingested and should be kept away from pets and kids (and you shouldn’t put your brush in your mouth). Generally, toxic pigments will have warnings on the label. For more detail, see my post Are watercolor paints toxic?

Series (Cost)

Many brands divide their paints into different “series” or price points. For example, in Daniel Smith, Series 1 is the cheapest and Series 5 is the most expensive.

This affects the pricing of the tube of paint, but it does not mean quality. Series 1 paints are no less vibrant, long-lasting, or anything else – it just has to do with what it’s made of and how rare or expensive the pigments are. Paints containing heavy metals such as cobalt and cadmium tend to be on the more expensive side, and paints containing rare precious minerals such as genuine lapis lazuli can be very expensive (and usually quite weak and low in pigment).

Tinting Strength

Is the color strong or weak? How much paint do you need to use to get a strong color? There are many reasons this could vary from paint to paint:

• Some pigments are stronger than others. For example, synthetic pigments in the Phthalo and Quinacridone families are notoriously strong, while mineral pigments such as Potter’s Pink and Terre Verte are notoriously weak.
• Some paints contain more pigment than others. For example, Da Vinci offers a strong Burnt Sienna Deep (PR101), while Winsor & Newton’s similar-hued Burnt Sienna made from the same pigment is much weaker.

In general, student grade paints contain less pigment than professional or artist grade paints. Very expensive pigments may also be weaker because it’s not cost-effective to include a lot of pigment.

Strong paints can be easier to use if you want very dark or vivid color, but can be difficult to mix with weaker paints because they tend to dominate mixes. Some artists prefer to use weaker or mid-strength paints because they are easier to control, or to keep their palette consistent in strength.

Lightfastness

The permanence of the paint over time. Is the color prone to break down and fade upon longterm exposure to light, or will it look as vivid in a decade as it does now? Paints that fade are called “fugitive.” A notoriously fugitive paint is Opera Pink. Many historical paints are also fugitive by today’s standards.

Professional artists who sell their work need lightfast colors because customers expect to buy a painting that will last for the ages on their wall. Beginners and hobbyists may not need to care much about lightfastness (but it’s fine if you do).

Lightfastness is generally considered a quality of the pigment(s), so a paint is only as lightfast as the least lightfast pigment in the mix. But in practice, it’s more complicated: lightfastness may also vary across batches of the same paint!

Two standard ways of testing the lightfastness of the a pigment are:

• ASTM: Ranges from I to V (Roman numerals 1 to 5), with I being the best. You will often see this written as “ASTM I” or “ASTM III.”
• Blue Wool Scale: Ranges from 1 to 8, with 8 being the best.

Not all pigments are rated by standard scales, and some are only rated in other media (such as acrylics and oils).

Paint brands often include their own lightfastness ratings on paint packaging, but each brand has a different scale and often they are not particularly trustworthy (since of course it’s in their best interest to say all their paints are great). They also don’t tend to individually test each batch.

You can conduct your own lightfastness tests; read about mine in Lightfastness Tests 2023.

Staining (vs Lifting)

Highly staining paints immediately stain the paper with some level of permanent color whereas non-staining paints can be lifted – mopped up with a dry paper towel when wet, or scrubbed with a damp paper towel when dry – to reveal plain white paper.

Neither staining nor lifting is better; they’re both good for different applications. Staining paints can be useful for the lower levels in a layered painting, because they won’t be affected by painting new, wet layers over them. Non-staining paints can be useful for applications like a sky where you want to lift out clouds.

Granulation

Granulating paints have visible flecks of color which lend texture to the final product. Non-granulating paints are smooth, more like ink. Some artists love granulation and some don’t, but many have mix of granulating and non-granulating paints on their palette for different purposes; for example, granulating blues or greens may be used to mix up greens for textured masses of foliage, while non-granulating blue may be used for a clear blue sky. Or maybe you want smooth leaves and a textured sky! It’s up to you.

Transparency (vs Opacity)

Is the paint totally see-through, totally opaque, or somewhere in between? Most watercolor paint is at least somewhat translucent, moreso when diluted. Transparency is a signature characteristic of watercolor. (Most other forms of paint, including acrylics and gouache, are opaque due to the binder, regardless of pigment.)

But not all watercolor paints are equally transparent. Some pigments, like those in the cadmium and cobalt families, tend to be quite opaque. Other pigments, like those in the quinacridone and phthalo families, tend to be very transparent.

In general, pigments with higher tinting strength can afford to be more transparent (the company doesn’t need to put in as much pigment to make the paint strong.)

Paint brands typically describe their watercolor paints as having one of 3-4 transparency categories:

• Transparent
• Semi-Transparent
• Semi-Opaque
• Opaque

Rewettability/Brush Feel

This is a more subjective one, and you won’t see it on a paint label, but it affects my preferences quite a lot. Paints vary in how easy they are to rewet, with some drying hard as a rock and others never quite getting hard. Those that are considered easy to rewet may also have a sticky brush feel. (I have a personal bugaboo against sticky paint, but that’s a “me” problem.)

This quality seems to vary most between brands. Brands that use honey as humectant, such as Sennelier and M Graham, often feel sticky to me, no matter the color. Many people love these brands for how easy to rewet they are. You may particularly appreciate them if you live in a dry climate and find your paints are always drying too hard. By contrast, Winsor & Newton tube paint tends to dry hard, which may be great for you if you live in a humid environment. (Their pan paint uses a different formulation and may be a good option if you like their colors but not how hard they get.)

Paints within the same brand may also vary in how rewettable they are. Sometimes this seems to be a quality of the pigment. Some specific colors/pigments often seem sticky to me, like Prussian Blue and Dioxazine Violet. Some that often dry hard are Potter’s Pink and many yellow ochres/raw siennas.

Summary/My Take

My personal preferences and recommendations in a nutshell:

• Grade/Quality: Artist grade
• Format: Tubes (usually using them to make my own dry pans)
• Size: 5ml for new/rarely used colors, 15ml for colors I know I will use up
• Brands: Da Vinci, Holbein, Daniel Smith, Schmincke, Winsor & Newton (your preferences will vary depending on what’s available and affordable in your region)
• Colors: Core Colors plus any interesting/seasonal/bonus colors of the moment

Here are some even more subjective preferences, in less of a nutshell:

• Transparency: I prefer mostly transparent; some opaque are useful for specific situations (e.g. opaque white or light yellow for adding last-minute highlights)
• Granulation: I prefer mostly non-granulating; some granulating are useful for specific situations (e.g. granulating brown for bark/rock texture); many people love granulation
• Staining: I prefer staining colors for layering, but it may be useful for specific colors to be liftable depending on use case (e.g. sky blues for lifting clouds)
• Lightfastness: All other things being equal I would prefer lightfast colors (lightfastness is often a tiebreaker between similar colors), but some fugitive colors are unique (e.g. Opera Pink)
• Toxicity: I tend to prefer to use nontoxic paints where possible, but there are some unique cobalt paints I can’t resist.
• Tinting Strength: I prefer high tinting strength colors; generally it’s helpful if most colors on the palette have similar tinting strength
• Brush Feel: I prefer paints that don’t feel “sticky”, so I avoid those with honey in the binder (reflected in my brand preferences).
• Single-pigment or no: I tend to prefer single-pigment paints for logistical reasons (more flexible for creating my own mixes), but I will buy a premade commercial mix if I use it very often.

I don’t expect you to be guided by my preferences, but I’m always curious about what artists think and have decided. Hearing the reasoning behind other people’s decisions helps me to make my own, even if they’re different. I hope this has helped you!