One of the most widely used and versatile pigments, ultramarine blue is used in cosmetics to produce various colours, including purple, pink, and green. It has also been used as a substitute for black pigments such as black iron oxide.
L’Oréal-owned colour cosmetics brand Urban Decay has utilised ultramarine blue to create the foundation shade range for Urban Decay’s Stay Naked Weightless Liquid Foundation, which offers more than 50 shades to suit a diverse range of skin tones.
While the use of ultramarine blue as a pigment is well-documented, the researchers hoped to study its optical properties.
“We have discovered a new possibility that ultramarine blue, widely recognized as a pigment, is involved not only in colour tone but also in optical effects that contribute to the goal of beautiful skin.”
True blue benefits
An experiment was conducted comparing a foundation with black pigment and another with blue pigment. Both foundations contained 0.053% of black and blue pigments respectively.
A half-face comparison experiment of two foundations was conducted with six female models and evaluated by trained aestheticians.
The experts judged the effects of the foundations, evaluating factors such as skin brightness, colour irregularities, and coverage.
They concluded that the foundation formulated with ultramarine blue pigment showed “superiority” with the following effects: improved coverage, improved skin uniformity, and concealment of skin wrinkles and blotches.
Then the foundations were further tested against the same formulation that was toned by a colourist under a D65 light source.
According to the study, the toned formula contained 0.43% of blue pigment. When applied to black and white contrast cards, no colour difference was detected between the foundation with blue pigment and the toned foundation with blue pigment.
When compared to the foundation with black pigment, the toned formula showed similar effects, including improved visual coverage, improved skin evenness and better concealment of wrinkles.
“Even though the isochromatic colour was the same, the following effects were still observed… In other words, it became clear that a major advantage of using blue pigments is that they bring about a noticeable difference in the finished makeup effect, even when toned to the same colour, and it is significant to consider the cause of the difference,” the researchers concluded.
Why go blue?
The team believes that ultramarine blue has outperformed black as a foundation pigment because more red light is reflected in the blue pigment compared to black pigment.
“This is due to the unique properties of blue pigments, in particular the high reflectance of red light in the long wavelength region inherent to ultramarine pigments.”
The researchers explained further: “Several cosmetic companies have reported that when red long-wavelength light strikes the skin, it penetrates and diffuses deep into the skin, making unevenness and coloration on the skin surface less noticeable, resulting in a more beautiful skin appearance.”
While this study was conducted with a focus on North Asian complexions, the researchers noted that more research needs to be done to find out the effect of ultramarine blue pigmented foundations have on other skin tones.
“This research has shown that ultramarine blue can replace black pigment and provide superior cosmetic benefits. In the future, we would like to incorporate this finding into the development of formulations that match the skin of people in various countries beyond Asia.”
Cosmetic effects of red-light reflection by ultramarine blue pigment
International Journal of Cosmetic Science
Fumiyoshi Ikkai, Carl Blaksley, Rena Hayashi and Alexander Jaspers
https://doi.org/10.1111/ics.12849