Here's a comprehensive breakdown organized by pairing type, with transparency/opacity for each pigment.
The Logic of Classic Pairings
Mixing complements — two paints from roughly opposite sides of the color wheel — can produce pure grays or achromatic neutrals. These pairs are invaluable for mixing dark neutrals and as signposts for color design decisions. Most classic pairings exploit this: two pigments that together span warm-to-cool, light-to-dark, and chromatic-to-neutral across their full mixing range.
The Essential Classic Pairs
🔵🟤 Ultramarine Blue + Burnt Sienna
The single most universally useful pairing in watercolor. Together they produce luminous warm and cool grays, rich darks, and anything from sky blue to earthy brown.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| French Ultramarine | PB29 | Transparent | Granulating, warm blue |
| Burnt Sienna | PBr7 | Transparent | Warm red-orange earth |
This is the universal shadow gray — Burnt Sienna + Ultramarine is one of the most useful mixes in watercolor. Add more blue for slate grays and dark blues; add more sienna for warm browns; mix 50/50 for a rich chromatic black.
🔵🟠 Ultramarine Blue + Burnt Umber
A darker, cooler version of the above. Produces some of the deepest near-blacks in watercolor.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| French Ultramarine | PB29 | Transparent | |
| Burnt Umber | PBr7 | Semi-transparent | Darker, cooler than Burnt Sienna |
Great for shadows, tree bark, architecture, and deep glazing darks. A workhorse for Sargent-style dark backgrounds.
🔵🟡 Prussian Blue + Raw Sienna (or Yellow Ochre)
Homer's essential pairing. Earthy, naturalistic greens and olive tones across the full value range.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| Prussian Blue | PB27 | Semi-transparent | Deep, greenish cool blue; high tinting strength |
| Raw Sienna | PBr7 | Transparent | Warm golden yellow-brown |
| Yellow Ochre | PY43 | Semi-opaque | Muted earthy yellow |
Mix toward blue for deep forest shadows; toward yellow for sunlit meadows and late-afternoon water. Homer used Prussian Blue as nearly his entire blue range.
🩷🟢 Quinacridone Rose + Phthalo Green (or Viridian)
The modern luminous complementary pair. Across their mixing range: vivid pinks/magentas → warm grays → rich forest greens.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| Quinacridone Rose | PV19 | Transparent | Brilliant cool pink; lightfast |
| Phthalo Green BS | PG7 | Transparent | Intense; needs restraint in mixing |
| Viridian | PG18 | Transparent | Softer, cooler green; more controllable than Phthalo |
Pairing Ruby Red (PV19) with Phthalo Green produces a range of gentle grays and browns that can replace pre-mixed neutral pigments entirely. Use Viridian if Phthalo feels too aggressive.
🔴🔵 Alizarin Crimson (or Quinacridone) + Phthalo Blue (or Cobalt)
The classic purple/violet mixing pair, also capable of deep warm darks.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| Permanent Alizarin Crimson | PR206 (DS) / PV19+PR177 (W&N) | Transparent | Modern lightfast version |
| Quinacridone Magenta | PR122 | Transparent | Cleaner purples than alizarin |
| Phthalo Blue GS | PB15:3 | Transparent | Cool, green-leaning; brilliant purples |
| Cobalt Blue | PB28 | Semi-transparent | Gentler; granulating; more neutral purples |
🟡🟣 New Gamboge + Ultramarine (or Dioxazine Violet)
Warm yellow paired with violet for deep shadows, muted greens, and autumn tones.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| New Gamboge | PY153 | Transparent | Warm orange-yellow |
| Dioxazine Violet | PV23 | Transparent | Very high tinting strength; deep blue-violet |
Use tiny amounts of violet — it's powerful. Together they produce rich olive greens and deep warm shadows.
🟡🔵 Hansa Yellow + Phthalo Blue GS
The modern split-primary "clean green" pair. Produces brilliant, fresh greens impossible to achieve with opaque yellows.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| Hansa Yellow Medium | PY97 | Transparent | Clean warm yellow; no chalkiness |
| Phthalo Blue GS | PB15:3 | Transparent | Intense; mix sparingly toward yellow |
For those wanting transparent mixing, Nickel Azo Yellow (PY150) — sold as Transparent Yellow by W&N and Schmincke — is an excellent option for clean, luminous greens.
🟠🔵 Transparent Pyrrol Orange + Cobalt Blue
Orange and blue complements for warm shadows, skies, and skin tones.
| Pigment | Code | Transparency | Notes |
|---|---|---|---|
| Transparent Pyrrol Orange | PO71 | Transparent | Brilliant warm orange; DS exclusive |
| Cobalt Blue | PB28 | Semi-transparent | Granulating; gentle neutralizer |
Their mid-mix produces soft peachy neutrals ideal for flesh tones and stone.
Transparency / Opacity Quick Reference
| Category | Transparent | Semi-Transparent | Semi-Opaque / Opaque |
|---|---|---|---|
| Blues | Phthalo Blue, Ultramarine, Indanthrone, Prussian Blue (semi) | Cobalt Blue, Prussian Blue | Cerulean Blue |
| Reds | Quinacridone Rose, Quinacridone Magenta, Permanent Alizarin | Cadmium Red (semi) | Cadmium Red, Vermilion |
| Yellows | Hansa Yellow, New Gamboge, Nickel Azo Yellow | — | Cadmium Yellow, Yellow Ochre, Naples Yellow |
| Greens | Phthalo Green, Viridian | Hooker's Green | Chromium Oxide Green |
| Earth Tones | Burnt Sienna, Raw Sienna | Burnt Umber, Raw Umber | Yellow Ochre, Indian Red |
| Violets | Dioxazine Violet, Quinacridone Violet | — | — |
The Key Principle
Many painters find that mixing too many pigments produces mud. With a well-chosen palette, generally two — but at most three — colors can create any hue you want. The classic pairings above work because each partner is a single pigment, biased toward its complement, allowing clean mixes all the way to neutral gray or dark. Stacking opaque pigments on top of each other is what kills luminosity — keeping your pairs transparent is the way to preserve that characteristic watercolor glow.