My Watercolor Color Library: A Pigment-by-Pigment Comparison

I've always been a little obsessive about color, obsessive enough to spend way too many evenings lining up watercolors on paper just to see how they really compare. This page isn't a finished project, it's a living library. Over the years I've pulled out the watercolors I own one by one and compared them by pigment code, and it keeps growing every time I add a new color.

My full-spectrum watercolor pigment swatch chart, comparing colors across brands by pigment code.

A quick key for reading the chart: if a swatch has no brand label, it's Schmincke. "DS" in front means Daniel Smith. "QoR", "W&N" (Winsor & Newton), and "Holbein" after the name mark those brands.

Why I Made This Watercolor Swatch Chart

As I mentioned in my supplies post, for a long time I thought in terms of brand: Schmincke is good, that other brand is weaker, and so on. But once I started comparing pigments one by one, I realized the real question isn't the brand, it's which pigment code you actually have in your hand. This chart is that curiosity made visible.

What a Watercolor Pigment Code Is, and How to Read One

Every watercolor tube carries a small code next to the color name, something like PB29, PG7, or PR254. The letter tells you the pigment's color family (PY: yellow, PO: orange, PR: red, PV: violet, PB: blue, PG: green, PBr: brown, PBk: black), and the number identifies the specific chemical pigment within that family. The same pigment code means different brands are using the same Colour Index pigment class. However, differences in processing, particle characteristics, concentration, dispersion, and binder formula can make the paint look and behave differently on paper.

Some tubes list more than one code (PY83, PR101, PV19, for example); this means the color comes from a blend of several pigments rather than a single one. That distinction doesn't show up when the paint is fresh out of the tube, but it matters once you start mixing on the palette: single-pigment paints tend to mix cleaner and more predictably, while multi-pigment paints can turn muddy when layered with other colors. I'll cover that in a dedicated post.

What the Symbols on a Watercolor Tube Mean

Every tube also carries a few more technical details next to the pigment code, and knowing how to read them helps a lot when shopping or planning a palette:

Lightfastness: shows how much a color will fade over time. Most brands use the ASTM scale: I (excellent, holds up for years), II (very good), III (fair, noticeable fading over time), IV-V (poor, can fade within months). Schmincke uses a star system (five stars being most lightfast), while Royal Talens uses a plus/zero system (+++ most lightfast, o least).

Transparency: usually shown with a small square symbol: empty/white means transparent, a diagonal line means semi-transparent, a half-filled square means semi-opaque, and a fully filled square means opaque.

Staining: marked with "ST", meaning the pigment stains the paper and is hard to lift or erase.

Granulation: marked with "G" (granulating, settles into a textured pattern) or "N" (non-granulating, lays flat and even). Some pigments deliberately leave a grainy, textured look on the paper, and that's not a flaw, it's a sought-after effect.

A few colors that caught my attention

Some pigments in Daniel Smith's PrimaTek line are made from real minerals or natural materials, which makes them behave differently from synthetic pigments. Three examples from my library:

Mayan Blue Genuine: a metal-free pigment inspired by ancient Mayan chemistry. Lightfastness II (very good), transparent, granulating, low staining.

Aussie Red Gold: a blend of PY83, PR101, and PV19. Excellent lightfastness, transparent, non-granulating, low staining.

Iridescent Electric Blue: contains mica, PW20, and PW6. Excellent lightfastness, transparent, noticeably granulating, non-staining.

A few colors from other brands stood out for different reasons. Schmincke's Brilliant Opera Rose is stunning on paper, but it's what watercolorists call fugitive: it contains a fluorescent additive that fades noticeably over time when exposed to light, unlike the ASTM-rated pigments above. It's a good reminder that a beautiful color and a lasting color aren't always the same thing.

Potter's Pink (PR233), also from Schmincke, is the opposite story: very good lightfastness, and one of the strongest granulating pigments in my collection, it separates into a grainy, textured pattern almost every time it touches wet paper.

Schmincke's Transparent Orange (PO71) lives up to its name: transparent means light passes through the pigment and reflects off the white paper underneath, which is why it layers and glazes so cleanly over other colors.

QoR's Phthalo Blue (Green Shade) is a fully synthetic pigment (PB15:3) with extreme tinting strength. A tiny amount goes a very long way, and it's one of the most powerful blues in my whole collection.

As I fill in more of the chart, I'll expand this list with the real data printed on each tube.

How to use this library

When buying a new color, look at the pigment code rather than the brand name; you can often find the same code in a more affordable brand. When planning a palette, mixing granulating and non-granulating pigments can add textural variety to a piece. And for any important work, especially anything you plan to sell or display long-term, pay attention to the lightfastness rating.

This library keeps growing

Not every watercolor I own is on this chart yet, I add new colors regularly. If you're curious how a watercolor behaves based on its actual pigment code rather than its marketing name, it's worth checking back on this page from time to time, since new comparisons get added with each update.

I'll publish that as a separate post as the library grows.

Frequently asked questions

What does a pigment code like PB29 or PG7 actually tell you? It identifies the color's true chemical source. If you find the same code across different brands, they're using the same Colour Index pigment class; however, differences in processing, particle characteristics, and binder can still affect how the paint looks and behaves on paper.

Is granulation good or bad? Neither, it's a matter of preference. Granulating pigments leave a textured, grainy look on paper; if you want a smooth, even surface, non-granulating pigments are the better choice.

Why does lightfastness matter? It tells you how resistant a color is to fading when exposed to light over time. For work that will be sold or displayed under light for a long time, pigments rated ASTM I or II are the safer choice.