Paint Pigments: Phthalo Blue (PB 15)

A profile of phthalo blue paint pigment, including its characteristics.

Paint Pigment Phthalo Blue PB15
Paint Pigment: Phthalo Blue PB16. Image: ©2007 Marion Boddy-Evans. Licensed to About.com, Inc
By
Marion Boddy-Evans
    Marion Boddy-Evans is an artist living on the Isle of Skye, Scotland. She has written for art magazines blogs, edited how-to art titles, and co-authored travel books.
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    Marion Boddy-Evans
    Updated January 12, 2018

    Characteristics: Phthalo blue is a bright, intense blue that's very dark when used thickly. Used as a thin glaze it's very transparent. Mixed with white it's an opaque, beautiful sky blue. Phthalo blue is available in green and red shades.

    Common Names: Thalo blue, monestial blue, Winsor blue, monastral blue, phthalocyanine blue, heliogen blue, intense blue, Old Holland blue, Rembrandt blue.

    Color Index Name: PB 15. PB15.6 (green shade). PB 16 (metal-free).
    (Color Index Explained)

    Color Index Number: 74100. 74160.

    Pigment Origin: Copper phthalocyanine, a synthetic organic pigment.

    Used for Painting Since: 1930s. (Invented in 1928.)

    Opacity/Transparency: Transparent.
    (Opacity Explained)

    Tinting Ability: Strong.
    (Tinting explained)

    Lightfastness Rating: ASTM I.
    (Lightfastness explained)

    Oil Paint Drying Speed: Slowish.

    Specific Notes:

    • Sometimes used as a cheaper alternative for cerulean blue.

    Quotes About This Pigment:
    "Prized for its mixing abilities, it [phthalo blue] has also become the basis of many student-range blues as it can be reduced considerably and still offer a strong color." -- Simon Jennings, Artist's Color Manual, p14.
    "As a blue pigment, [phthalo blue] shares none of the luxuriant hue of ultramarine; but its importance lies more in the fact that it absorbs red and yellow almost totally, while transmitting or reflecting blue and green." -- Philip Ball, Bright Earth, p279.