Blue opaque pigment" refers to a class of blue-colored pigments that are non-transparent or have low translucency, meaning they effectively cover underlying surfaces or layers when applied. There are several types of blue pigments that are opaque, each with different chemical compositions, properties, and uses. Here's a breakdown:
🔵 Common Types of Blue Opaque Pigments
1. Ultramarine Blue (PB29)
Chemical composition: Sodium aluminosilicate with sulfur.
Appearance: Deep, vibrant blue.
Opacity: Semi-opaque to opaque.
Lightfastness: Excellent.
Properties:
Non-toxic.
Slightly chalky texture.
Can become dull in oil mediums.
Uses: Widely used in oil, acrylic, and watercolor paints.
2. Cobalt Blue (PB28)
Chemical composition: Cobalt(II) aluminate spinel.
Appearance: Cool, clean blue with slightly grayish tone.
Opacity: Semi-opaque to opaque.
Lightfastness: Excellent.
Properties:
Very stable and permanent.
Expensive due to cobalt content.
Uses: Fine art, ceramics, glass.
3. Cerulean Blue (PB35 or PB36)
Chemical composition: Cobalt(II) stannate (PB35) or chromium-based (PB36).
Appearance: Light sky blue to turquoise.
Opacity: Opaque.
Lightfastness: Excellent.
Properties:
Slight granulation in watercolor.
Very stable.
Uses: Ideal for skies and seascapes in painting.
4. Phthalo Blue (PB15:3 or PB15:1)
Chemical composition: Copper phthalocyanine.
Appearance: Intense, dark blue with greenish or reddish undertone.
Opacity: Generally transparent, but can be made opaque by mixing with white or fillers.
Lightfastness: Excellent.
Properties:
High tinting strength.
Versatile in all media.
Note: While naturally transparent, it is sometimes included in "opaque" formulations for commercial paints.
5. Indanthrone Blue (PB60)
Chemical composition: Synthetic anthraquinone derivative.
Appearance: Deep, dark blue, leaning slightly towards purple.
Opacity: Semi-opaque.
Lightfastness: Excellent.
Properties:
Very good covering power.
Rich and intense.
✅ Characteristics of Opaque Blue Pigments
Property Opaque Blue Pigments
Opacity High, masks layers beneath
Covering Power Strong
Mixing Behavior Can dull or dominate mixtures
Durability Most are highly lightfast and stable
Toxicity Cobalt-based pigments may be mildly toxic
🎨 Applications
Fine Art: Acrylics, oils, and watercolors.
Ceramics: Glazes and underglazes.
Industrial Coatings: Automotive, plastics, building materials.
Cosmetics: Specially formulated safe versions used in eyeshadows, etc.