Cobalt Blue Deep

Description

Cobalt Blue Deep (PB72) is a handmade single-pigment cobalt–zinc aluminate spinel blue pigment. It produces a deep, luminous blue with a cool, violet leaning undertone and a rich, saturated masstone. Compared to traditional cobalt blues, this pigment offers a darker value and higher chroma while still retaining the gentle granulation and clarity that painters associate with cobalt colors.

In use, Cobalt Blue Deep gives a powerful yet refined blue ideal for intense skies, deep water, architectural shadows, and cool passages in landscape and figure work. It has strong tinting strength without the overwhelming staining of phthalo blues, making it easier to control in mixtures and lifts. It mixes beautifully with with reds and earths for complex violets and shadow neutrals that remain clean rather than muddy.

This spinel-based 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 combines the reliability of traditional cobalt blue with a deeper, more dramatic chroma, offering a versatile “workhorse” blue for subtle glazing and bold, saturated passages.

History

Cobalt-based blues first appeared as modern synthetic pigments in the early 19th century, when chemists developed stable cobalt aluminate blues as an alternative to fragile historical pigments. Cobalt Blue Deep (PB72) represents a later evolution in this family: a complex spinel pigment where cobalt is combined with zinc and aluminum oxides to produce a deeper, more intense blue than conventional cobalt aluminate.

Originally developed for industrial applications (such as high-performance coatings, enamels, and ceramics) PB72 was valued for its exceptional lightfastness, heat stability, and resistance to harsh environments. Its strong chroma and clean hue later attracted the attention of paintmakers, and it began to appear in artist paints under names like “Cobalt Blue Deep.” Today, Cobalt Blue Deep is appreciated by painters who want the beauty and reliability of cobalt with added depth, saturation, and mixing range.

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–zinc aluminate spinel

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

Lightfastness: Best

Opacity: Semi-opaque

Other Names: Cobalt Blue Deep, Cobalt Zinc Aluminate Blue, Cobalt Zinc Blue

Color Index Code: PB72