Cobalt Tin Alumina Blue Deep

Description

Cobalt Tin Alumina Blue Deep (PB81) is a handmade single-pigment cobalt tin alumina blue spinel pigment. It is based on a complex spinel structure formed from cobalt, aluminum, and tin oxides, creating an extremely stable crystalline matrix. It produces a deep blue that leans slightly toward violet, with a rich, saturated masstone and a refined, velvety character. Compared to traditional cobalt blue (PB28), this pigment is typically darker and a touch redder, offering a more mysterious blue violet tone while still retaining the clarity and control painters expect from cobalt colors.

In use, Cobalt Tin Alumina Blue gives a powerful and controlled blue ideal for twilight skies, deep water, architectural shadows, night scenes, florals, and cool passages in figure work. It has strong tinting strength without the overwhelming staining of phthalo blues, making it easier to lift, soften, and refine. It mixes beautifully with cool and warm reds to create complex violets, with earths for deep blue-grays and shadow neutrals, and with yellows for subdued, moody greens that stay crisp rather than muddy.

This spinel pigment is chemically inert, heat-resistant, and highly resistant to acids and alkalis, which makes it suitable across a wide range of binders and mediums. In artist’s colors it offers a distinctive blue–violet cobalt that can function as a statement color in its own right or as a sophisticated mixing blue for atmospheric, low-key, or classical palettes.

History

Cobalt spinel blues emerged in the 20th century as part of a broader family of modern ceramic pigments, developed when chemists began incorporating cobalt and other metal ions into robust spinel crystal structures to withstand extreme kiln temperatures and harsh environments. Cobalt Tin Alumina Blue (PB81) is produced by calcining cobalt, aluminum, and tin oxides at high temperature until they interdiffuse into a homogeneous spinel matrix often described as a cobalt tin alumina blue spinel.

Initially designed for use in ceramics, enamels, and high-performance coatings, PB81 was valued for its excellent lightfastness, heat stability, and resistance to chemicals. Over time, its deep, slightly violet-leaning hue attracted the attention of paintmakers, and it began to appear in select artist ranges and specialty watercolor lines. Because it is rarely used compared to more common cobalt blues, PB81 remains something of a connoisseur pigment, appreciated by painters who want the reliability of cobalt with a deeper, more violet character and a unique place on the blue–violet spectrum.

Health and Safety

Precautions:

Keep out of reach of children and pets.

Do not consume.

Not for cosmetic or food usage.

Do not spray apply.

For further health information contact a poison control center.

Use care when handling dry pigments and avoid dust formation.

Use particular caution with fibrous, fine, or toxic pigments.

Do not eat, drink, or smoke near dry pigments.

Avoid breathing in pigment dust and use a NIOSH-certified dust respirator with sufficient rating for dry pigment.

Wash hands immediately after use or handling.

If dust is likely, always wear protective clothing to keep out of eyes, lungs, off skin, and out of any contact as well as keep area ventilated.

This product may contain chemicals known by the State of California to cause cancer, birth defects, or reproductive harm.

Warnings and bottle information are abbreviated.

Pigment Information

Pigment Type: Synthetic (Inorganic) cobalt tin alumina blue spinel

Suitable Mediums: Watercolor, Oil, Tempera, Acrylic, Lime / Fresco, Ceramic and cement applications

Lightfastness: Best

Opacity: Semi-opaque

Other Names: Cobalt Tin Alumina Blue, Cobalt Tin Alumina Blue Spinel, Aluminum Cobalt Tin Blue

Color Index Code: PB81