Rating the Watercolor Pigment Families

While updating Color Spotlights to add more pigment details and use more standard naming for some of the colors, I began to notice connections between pigments in terms of their chemical families. Now, I know nothing about chemistry, so this is pure pattern-matching. For example, many pigments are “benzimidazolone,” and they’re quite different from each other: yellows, purples, browns… Could you make an entire palette from just benzimidazolones?? I decided to group the pigments by chemical category and rate each one.

Now, I don’t know much about chemistry. Don’t know much biology. Don’t know much about science book. If you want that, go to handprint.com. I’m purely going off of pigment names here. But I’ll start by borrowing some handprint info to give you a basic tour of the categories.

Overarching Categories

There are many ways to categorize pigments. Here are some useful ones:

• Synthetic vs natural: Synthetic pigments are made in a lab, and natural pigments are found in nature, such as mining them from the earth.
• Organic vs inorganic: Pigments are typically discussed as being organic or inorganic in the chemical sense: organic pigments contain carbon, and inorganic ones do not. Generally, mineral or metal-based pigments are inorganic. Many modern pigments are “synthetic organic” meaning they were created in a lab from chemicals containing carbon compounds.

	Inorganic	Organic
Natural	Natural iron oxides (earth pigments)	Historical dyes, like madder root and natural indigo (pigment codes start with N)
Synthetic	Synthetic iron pigments (earth pigments & Prussian Blue); cadmium; cobalt; chromium; manganese; ultramarine	Most modern pigments, including quinacridone, phthalo, pyrrol, perylene, azo, anthraquinone

Inorganic

Earth Pigments (Iron Oxides)

I’ve discussed earth pigments before; this is a case where the colloquial term, “earth pigments,” more or less aligns with the chemical family, iron oxides.

Generally, specific pigment numbers are supposed to refer to natural ones (PY43, PBr7, PR102) while others are supposed to refer to the corresponding synthetic ones (PY42, PBr6, PR101), but paint companies don’t always adhere to this. Iron oxides are all generally brownish and low-chroma, and range from more yellow ones (PY42/PY43) to more orange or red ones (PR101/PR102) to more brown ones (PBr6/PBr7). Some black paints are also iron oxides. Many of these pigments have multiple “personalities” and can make paints that range quite a bit in terms of hue and levels of transparency and granulation.

• Yellow Ochre (PY42 or PY43)
• Gold Ochre (PY42)
• Mars Brown (PR101)
• Venetian Red (PR101)
• Indian Red (PR101)
• Violet Iron Oxide (PR101)
• Transparent Brown Oxide (PR101)
• Transparent Red Oxide (PR101)
• Terra Cotta (PR102)
• Raw Sienna (PBr7 or PY42)
• Raw Umber (PBr7)
• Burnt Umber (PBr7)
• Van Dyck Brown (PBr7)
• Lunar Black (PBk11)

You could also argue that synthetic Prussian Blue (PB27) belongs on this list, as it is derived from iron, but in terms of its pigment qualities it doesn’t “feel” earthy: it is transparent, smooth, and blue!

Rating: A. I usually have 2-3 of these on my palette. I am on record as finding bright colors more interesting than muted ones, but there can be a lot of beauty in mutedness, and landscape browns are often more attractive and realistic when painted with earth pigments compared to mixed browns. These colors are also just so flexible, with many different hues and versions available to match your preferences.

I like the simplicity and longevity of earth paints; “painting with dirt” is an idea that is easy to understand, and there is also something lovely about painting with the same sorts of ancient colors that our cave-painting ancestors did.

I don’t like only painting with earth pigments, but as most of the families in this list contain pretty limited hue ranges, that’s true of all of them. I would definitely miss them if they disappeared.

Cadmium

Very bright and opaque reds, oranges, and yellows with strong tinting strength. Generally smooth and not granulating, though this may vary. Cadmium pigments are probably the most toxic ones available on the market today (though still far less toxic than historical paints such as lead-tin yellow or genuine vermilion).

• Cadmium Yellow (PY35)
• Cadmium Orange (PO20)
• Cadmium Red (PR108)

Rating: D. I can say that because I don’t use them and never have, so I don’t know what I’m missing, but I can safely say you can easily live without these. They are bright, but there are plenty of other bright yellows, oranges, and reds on the market.

Cobalt

Opaque blues, greens, and violets, usually light- to mid-valued with strong tinting strength and moderate to high granulation. Cobalt pigments are toxic, but the risk is generally considered low for watercolor paints, especially since cobalt is not water soluble.

• Cobalt Yellow (PY40), aka Aureolin
• Cobalt Violet (PV14)
• Cobalt Blue (PB28)
• Cobalt Blue Deep (PB74)
• Cerulean Blue Genuine (PB36)
• Cobalt Turquoise (PG50, PB28, or PB36)
• Cobalt Green (PG50)

Rating: B. I really love some of these paints, especially Cobalt Blue and Cobalt Turquoise, both of which I usually have on my palette. There is really nothing else like them. This is not a category that could be easily replaced if they all disappeared tomorrow. I take toxicity more seriously than many (i.e. don’t cadmiums), but I have decided that the joy of using cobalts outweighs the relatively small risk. The rating is brought down only because I don’t tend to prefer opaques as much as transparents (some of the upcoming families are curvebreakers), and because there are a few duds in here.

Chromium

Historical, discontinued chrome pigments were toxic and generally replaced by cadmiums, but the ones that remain are generally nontoxic, earthy, and may be opaque or granulating. You could also classify some of the cobalt pigments, such as Cerulean, as chromium.

• Viridian (PG18)
• Chromium Oxide Green (PG17)
• Naples Yellow Deep (PBr24)

Rating: C+. Kind of a random group. NYD is the only one I really like. They are classics though.

Manganese

An interesting mix of high-granulating paints in seemingly unrelated hues. As I understand it it, manganese paints are somewhere between cadmium and cobalts in toxicity; care should be taken when using them, and they can produce negative externalities in their production.

• Manganese Violet (PV16)
• Manganese Blue (PB33) – all but discontinued
• Manganese Brown (PY164)

Rating: D. These colors are interesting, but not interesting enough to justify the extra mental and emotional labor of dealing with paint water you can’t discard normally. They also tend to be quite weak colors. Pass.

Ultramarine

One of the older synthetic groups, this is named for its hue, but made from clay, sodium, silica, and sulfur.

• Ultramarine Blue (PB29)
• Ultramarine Violet (PV15)
• Ultramarine Red (PR259) – rare; really a pink

Rating: B. It’s limited, but mighty. I tried not to include too many super-small groups, but I think this one is important: Ultramarine Blue is in nearly everyone’s palette.

Organic

Quinacridone

Mostly magentas, violets, and reds, with a few oranges/golds (though those are mostly discontinued). All these pigments are very transparent, staining, and nontoxic. Intensity varies, but mostly they are quite high-chroma, with some, like PR122, being basically primary.

• Quinacridone Burnt Orange (PO48) – discontinued
• Quinacridone Gold (PO49) – discontinued
• Quinacridone Magenta (PR122)
• Quinacridone Fuchsia (PR202)
• Quinacridone Burnt Scarlet (PR206) – discontinued
• Quinacridone Coral (PR209)
• Quinacridone Rose/Red (PV19) and Quinacridone Violet (PV19)
• Quinacridone Pink (PV42)
• Quinacridone Purple (PV55)

Rating: A+! This contains some of my favorite colors. I mean, I love pink. I also love staining and transparency, and most of these colors also have high tinting strength, a very wide value range and a luminous, glowing feel.

Phthalocyanine

Blues and greens. Super-strong, transparent, staining, nontoxic; and among the highest-chroma blues and greens you can possibly get. Includes classic primary cyan PB15:3.

• Phthalo Blue Green Shade (PB15:3)
• Phthalo Blue Red Shade (PB15:1 or PB15:6)
• Phthalo Turquoise (PB16)
• Phthalo Green Blue Shade (PG7)
• Phthalo Green Yellow Shade (PG36)

Rating: A+! These colors are gorgeously strong and transparent, and are unbeatable mixers for those oh-so-important greens. They’re at home in a landscape or in a fantasy environment. Some find them too strong, but I don’t know that I think there is such a thing. With their consistent transparency, strength, and color family, they also have a strong “family identity.”

Pyrrol (Diketo-pyrrolo-pyrrole)

Bold oranges and reds, ranging in transparency from transparent to nearly opaque.

• Transparent Pyrrol Orange (PO71)
• Pyrrol Orange (PO73)
• Pyrrol Scarlet (PR255)
• Pyrrol Red (PR254)
• Pyrrol Crimson (PR264)

Rating: C. These are extremely good colors on paper but, subjectively, I simply don’t use any of them. This is the class of colors most commonly put forward as a nontoxic replacement for the cadmiums, and while I agree that there are some great cadmium lookalikes here, I’m not tempted by the cadmiums to begin with; I simply tend not to like opaque paints that much. PR264 and PO71 are the only ones I’m remotely tempted by, but even they are palette-optional.

Perylene

Mostly muted reds, with one random greenish black. Tend to be strong, transparent, staining, nontoxic. Most are moderate to low-chroma. Perylenes tend to undergo a large drying shift.

• Perylene Scarlet (PR149)
• Perylene Red (PR178)
• Perylene Maroon (PR179)
• Perylene Violet (PV29)
• Perylene Green (PBk31)

Rating: B-. The drying shift is a big killer for most of these. I have also noticed that one some papers, perylene pigments will also dry with little white dots where the paper shows through, for reasons I don’t understand. This can also make them look lighter when dry than they appeared when wet. I find drying shift difficult to handle because it can throw off the value range of the painting. With that said, these are also among the darkest colors you can get, which can be a big help in setting values if you make sure to make them a bit stronger than you think you need.

Azo

The Azos are such a huge group that I am going to further subdivide them.

Benzimidazolone

Sometimes called “benzimidazolone,” “imidazolone,” or “azo,” and sometimes renamed to something else altogether! This group of paints is surprisingly wide-ranging in hue, including yellows, oranges, reds, and browns. They tend to be transparent and of moderate to high tinting strength.

• Imidazolone Lemon (PY175) aka Lemon Yellow
• Azo Yellow (PY151) aka Aureolin Modern
• Imidazolone Yellow (PY154) aka Pure Yellow, Da Vinci Yellow, Winsor Yellow
• Benzimidazolone Orange Deep (PO36)
• Benzimidazolone Orange (PO62) aka Winsor Orange
• Benzimidazolone Bordeaux (PR171) aka Napthamide Maroon
• Benzimidazolone Carmine (PR176) aka Carmine, Rose Madder
• Benzimidazolone Violet (PV32) aka Bordeaux
• Imidazolone Brown (PBr25) aka Dragon’s Blood

Rating: B. I really like most of these colors, though for the most part they are not my top favorites (PY151 is the only one in my current palette). That said, they are mostly very solid, and I’m impressed that they’re so diverse.

Hansa (Arylide/Diarylide)

Hansa is a brand name; chemically these should be called arylide or diarylide, depending on whether there are one or two… aryls, I guess. These are bold, high-chroma, semi-transparent yellows.

• Hansa Yellow Light (PY3)
• Hansa Yellow Deep (PY65)
• Brilliant Hansa Yellow (PY74)
• Hansa Yellow Medium (PY97)
• Diarylide Yellow (PY83)

Rating: A-. A strong showing, some great yellows are in here. Because so many other families do make yellow, I could get along without these, but I like them quite a bit, especially PY97 and PY65.

Disazo Condensation

Don’t ask me what this means.

• Yellow Sophie (PY93)
• Transparent Yellow (PY128)
• Geranium Red (PR242)
• Transparent Brown (PBr41)

Rating: D+. I guess these colors are fine, but to me they are of marginal importance because they are difficult to find and generally only available from one or two brands (Sennelier, Rembrandt, Schmincke, and Schmincke, respectively). None of these are brands I use much or have good access to. Plus, all of these colors are easily replaced or duped with other, more easily available colors; the first two are generic bold yellows, there’s a scarlet red that’s a lot like PR188. The transparent brown is the most unique, but even it is pretty similar to Transparent Brown Oxide (PR101) or Imidazolone Brown (PBr25).

Naphthol

Reds, ranging tightly from scarlet to middle red, generally transparent.

• Napthol Scarlet (PR188)
• Naphthol Red (PR112) aka Permanent Red
• Naphthol Red (PR170) aka Permanent Red
• Naphthol Red (PR170:1)
• Naphthol Red (PR187) aka Sanguine Red

Rating: C-. I tried not to compare lightfastness too much as many of these groups have fugitive members that I generally omitted, but it’s hard not to notice that the majority of these paints are marketed as permanent but have less-than-stellar lightfastness ratings. It’s hard to distinguish them because they look and behave similarly; they are lacking in special, unique qualities. And generally, they are not as nice as other reds. I like PR188, but even I have to admit it’s not the best scarlet with its tendency to cauliflower.

Metal Complex

Highly dispersive, highly transparent yellows derived from metals.

• Nickel Azo Yellow (PY150)
• Nickel Dioxime Yellow (PY153) – aka Indian Yellow; discontinued
• Copper Azomethine Green Gold (PY129)

Rating: A. I tried not to include families that were too small, but this family is mighty, with both Nickel Azo Yellow and Green Gold being among my favorite and most unique yellow mixers.

Isoindol(in)one

Rounding out the azo’s we have one more small group of yellows.

• Isoindolinone Yellow (PY110)
• Isoindoline Yellow (PY139)

Rating: C+. Personally important to me because I have a soft spot for PY110, but tbh it’s easily replaced with Hansa Yellow Deep (PY65) and I have never really used PY139.

Anthraquinone

A wide variety hues, with moderate chroma and high transparency.

• Anthraquinone Yellow (PY147) – Roman Szmal exclusive
• Alizarin Crimson (PR83)
• Anthraquinone Red (PR177)
• Anthraquinone Scarlet (PR168)
• Indanthrone Blue (PB60), aka Indanthrene Blue or Anthraquinone Blue

Rating: B-. This is an extremely interesting group because it is the only group that contains a wide range of colors that could make up a complete palette on its own. I really want to give it points for that, and for containing Indanthrone Blue, which I adore. But as with the Naphthols, some of the very popular pillars of this group are notoriously lacking in lightfastness, including the fugitive Alizarin Crimson and even its “permanent” replacement PR177.

Hybrid Organic/Inorganic

Maya

Based on historical pigments developed by Mayan scientists and ceramicists from a mix of organic and inorganic natural ingredients, and used for centuries in pre-colonization Mesoamerica, modern synthetic Maya pigments are also hybrid or organic and inorganic. The ones listed are patented and may be listed under the trademark MayaCrom.

• Maya Yellow (PY223, PY224, or PY226)
• Maya Orange (PO84)
• Maya Red (PR286, PR287, or PR288)
• Maya Violet (PV58)
• Maya Blue (PB82, PB84)

Rating: ??? I have never tried any of these. The commercial options I am aware of (Daniel Smith, Turner, Kremer) do not have a great reputation for strength or lightfastness, which is a shame, because the history is intriguing, the hybrid technique is unique, and this is the only other “family” that could make a complete palette!

Conclusion

If I had to pick my top three families to save from a burning chemistry lab, they would be phthalo, quinacridone, and hansa, which conveniently form a cyan/magenta/yellow modern primary triad. If I could get a fourth family, I’d rule in earth pigments/iron oxides, because they add a whole other dimension of texture and make it so much easier to paint convincing landscapes. The metal complex category would get my next nod.

But I’m glad I don’t have to! Practically, the exercise of limiting yourself to specific families is a fool’s game, because because the families tend to produce paints of similar hues and other qualities. As I noted above, Anthraquinone and Maya are the only families that could produce a complete palette on their own, and both would require sourcing paints that are quite difficult to find.

If anything, I think the best option is to choose your 1-2 favorites from as many families as possible, rather than trying to stick to just a few. For example, a “max one of each” palette might look like this:

• Azo: Hansa Yellow Medium
• Quinacridone: Quin Rose
• Ultramarine: Ultramarine Blue
• Phthalo: Phthalo Blue GS
• Cobalt: Cobalt Turquoise
• Chromium: Naples Yellow Deep
• Earth: Transparent Red Oxide
• Perylene: Perylene Maroon
• Pyrrol: Pyrrol Crimson
• Anthraquinone: Indanthrone Blue

This is a pretty good palette! In reality, though, I’d prefer to take more earths (NYD really had to pinch-hit for an earth yellow), and more azo yellow options (for example, including a metal complex would be great; though I guess if I weren’t stubbornly snubbing the Cadmiums I could get my bright yellow from Cadmium Yellow and use my Azo slot for Nickel Azo Yellow.)

Though honestly, ignoring chemical composition entirely is a fine thing for artists to do! I looked into this out of perverse interest.

What color families did I miss? What did I say about chemistry that was laughably wrong? Why are you mad that I rated your favorite paints so low? Chime in in the comments!