[ Microscopic comparison of substrates ]
Microscopic view of
(mica vs. borosilicate)
Scanning electron microscope images of natural mica and synthetic
borosilicate substrate particles reveal the more regular structure of the
latter. Fewer steps and edges on the borosilicate flakes give them better
reflectivity once they are coated with other substances. ECKAR T GmbH
Mica flakes (top) and borosilicate flakes (bottom), all
coated with titanium dioxide. The smoother borosilicate
particles give a brighter, more uniform color distribution
and a better-looking final product. ECKART GmbH
sun-tanned, while another line of cosmetics might emphasize deep reds that
flatter African American women.
Lipstick, eye shadow
Lipsticks were originally made of wax
crystals that are similar to wax polishes
made for shoes and cars, Lochhead said.
In recent decades, lipstick formulators
have added polymers for more stability
and tiny silicone resin cushions to reduce
the likelihood that lip color will come off
on coffee cups and shirt collars.
Today, lipsticks contain blends of red,
yellow and blue lake pigments, sometimes with a dash of titanium dioxide to
lighten reds into pinks. Synthetic “
pearl-izing” agents, such as bismuth oxychloride, give a frost or shimmer to the color.
Lip glosses contain less wax and more oil
than solid-stick lip colors.
Mascara must separate the eyelashes
as well as color them. It needs to be as
glossy and dark as the cosmetic scientist
can make it, and its pigments must be
compatible with polymers that have high
extensional viscosity, so that the mascara
forms a cylindrical film that adheres to
the keratin in eyelashes.
However, the U.S. FDA gives research-
ers a limited choice in safe pigments for
use on eyelashes because of their proxim-
ity to the eyes’ mucous membranes,
Lochhead said. Another caveat for
mascara formulators is that, in the high
humidity at the eyelash level, the bot-
tom of each lash shaft swells more than
the tip, producing the characteristic curl
away from the eye. Completely water-
proofing the lashes would bar water
vapor from absorption into the lashes—
which would droop unattractively.
According to Lochhead, “The reason
people don’t think there’s science in there
is that [cosmetics are] commonplace,” he
added. “People think that because they’re
so common, they can’t be very sophisti-
Researchers are continuing to develop
new composite colorants that diffract and
scatter light without drawing attention
to themselves. Photonics, the ultimate
enabling technology, will undoubtedly
help millions more people to put their
best face forward to the world. t
Patricia Daukantas ( firstname.lastname@example.org) is the
senior writer/editor of Optics & Photonics News.
[ References and Resources ]
>> P. Daukantas. “Photorealistic Rendering: Making the Virtual into Reality,” Opt. Photon. News
20( 1), 34 (January 2009).
>> C. Dumousseaux et al. “Compositions for Making Up Keratinous Materials,” U.S. Patent Application 20090117160 (May 7, 2009).
>> L. Huang et al. “Cosmetic compositions and method which impart a healthy appearance to
skin,” U.S. Patent Application 20090155373 (June 18, 2009).
>> R. Johnson. “What’s That Stuff? Lipstick,” Chem. Eng. News 77( 28), 31 (July 12, 1999).
>> R. Y. Lochhead and L. Anderson. “Intellectual Property Trends in Color Cosmetics,” Household and Personal Products Industry magazine, August 2009; online at www.happi.com/
>> M. Tan et al. “Compositions containing optical diffusing pigments,” U.S. Patent No. 6,511,672
(Jan. 28, 2003).
>> U.S. Department of Health and Human Services. “Cosmetics and Your Health: Frequently
Asked Questions,” online at www.womenshealth.gov/faq/cosmetics-your-health.cfm.
>> R. Winter. A Consumer’s Dictionary of Cosmetic Ingredients, 7th ed. (New York: Three Rivers
>> H.D. Wolpert. “Optical Filters in Nature,” Opt. Photon. News 20( 2), 22 (February 2009).
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