Pigment Selection for Cosmetic Formulations

Basics of Color Cosmetics

• Hue – This is the actual color, e.g., red, blue or yellow
• Value or Luminosity – The higher the value or luminosity, the more white that is in the color
• Chroma or saturation – The intensity of the hue relative to the value or luminosity of the color

• Pantone color charts
• The Munsell color system
• The British Colour Council Dictionary of Color Standards

Opaque vs. Translucent vs. Transparent - Know The Difference!

• Opaque - Solid color, which cannot be seen through. This is an important property of color cosmetics where coverage is required e.g., foundations, concealers, lipsticks.


• Translucent - Objects appear cloudy with a color; they cannot be seen through completely. This is an important property of color cosmetics where subtle color is required. Here, the users skin tone is desired to be enhanced but not completely covered e.g., translucent ‘finishing’ powders, tinted moisturizers, tinted lip glosses.


• Transparent - Objects can be seen through, and appear optically clear although colored. This is more for aesthetic effects of the product. Also, where the intensity is quite weak, will wash off with no lasting color on the user’s skin e.g., a variety of every day personal care cleansers and lotions with colored accents. Bronzers used in self-tanning products also fit into this category although their use is in much higher concentrations to leave a lasting stain on the user’s skin.

Types of Pigments

Organic Pigments

• Organic colorants are all transparent on the skin, with various levels of chemical and physical stability. They are capable of producing a range of bright colors for a variety of visual effects.


• They achieve best stability in the pH range of 4 to 9 and are often unstable in the presence of metal ions. Chelating agents can be a good addition to formulas where metal ions might be otherwise present, so long as the chelating agent does not have a detrimental effect on other components of the formulation (such as some fake tanning agents).


• Organic colorants can also be classified chemically by their structures with varying stability, such as:
  
  
  • Azo colorants
  • Xanthenes
  • Triarylmethanes
  • Quinoline
  • And indigoid
  
  

  Organic Pigments	Examples
  Lakes	FD&C yellow 5 FD&C yellow 6 FD&C Red 3 FD&C Blue 1 FD&C Red 40
  Toners	D&C Red 6 D&C Red 7 D&C Red 34
  True Pigments (Most Stable Form)	D&C Red 30 D&C Red 36



• Certain organic colorants can also be used to stain the skin or the lips, for various effects. So called ‘bronzers’ used in fake tanning products usually use a combination of dyes that are able to stain the skin and are resistant to easy wash off.
  
  While some colorants would normally be used only in wash off products, in bronzers, the ‘stain’ effect is desirable to give an instant ‘tanned’ appearance. Examples of colorants used to obtain a tanned stain in the skin include:
  
  
  • FD&C Blue 1
  • FD&C Yellow 5
  • D&C Red 33
  
  Other skin staining dyes that may be used include those that are oil soluble and stain the lips. These typically include:
  
  
  • D&C Red 21
  • D&CRed 27
  • D&C Orange 5
  
  All skin staining colorants are prone to risks of causing allergic reactions. Particularly the oil based colorants used in lipsticks. Appropriate consumer safety tests should be conducted to confirm safety before products move beyond the sample and development stage

Inorganic Pigments

• They are used for their opaque color coverage, making their use particularly suitable in face and eye make ups.


• They are usually duller in appearance than organic pigments. However, they have much better stability and can be enhanced through various coatings for decorative effects (pearlescent colors).


• They are stable to heat and light but may be sensitive to extremes of pH.

1. Iron oxides: It has three basic shades - yellow (CI 77492), red (CI 77491) and black (CI 77499). Through careful blending, these three colors are able to produce a vast array of:
   
   
   • Tans
   • Umbers
   • Browns
   • And siennas
   
   Making them ideal for use in foundations, blushes and lip products.


2. Chromium oxides: It has two basic types:
   
   
   • One provides a dull yellow/green hue
   • And the other a bright bluish/green hue.


3. Ultramarines: They can vary significantly in color, from blues and violets through to pinks and greens.
   
   
   • No matter the color, they all have the same CI number and INCI designation.
   • Also, they are unstable to low pH conditions.


4. Titanium dioxide: It is widely used in color cosmetics where opacity and coverage is required.
   
   
   • It is extremely stable to heat and light
   • And easily incorporated into a variety of colored cosmetic and personal care products.


5. Zinc oxide: It has a lower intensity of ‘whiteness’ than titanium dioxide and less coverage.
   
   
   • It does impart antibacterial and fungicidal properties
   • And has good heat and light stability.

Selecting the Right Pigment

• Reduced shade - This is the lighter of the two colors, and gives a visual reference for how the color will look when it is ‘diluted’. That is, when added to base product at less than 100% strength.


• Full shade - This is the darker of the two colors, and gives you a visual reference for how the colorant looks at 100% strength.

• 1-15µm provides velvety, soft and matte shimmer visual effects
• 5-25µm provides a silky skin feel and smooth, silky and satin effects
• 10-50µm provides strong color and some sparkle effect
• 20-150µm provides a strong and pronounced sparkle effect
• Larger particle size will provide an even stronger sparkle effect

Creating Pearlescent Effects

• Bismuth oxychloride
  
  
  • Produces a silvery-grey pearlescent effect
  • At 8µm, it creates a smooth, opaque luster
  • At 20 µm, it creates a brilliant sparkling look


• Treated pigments
  
  
  • Pigments can be surface treated for enhanced aesthetic performance as well as for process improvements
  • Aesthetic improvements include : better skin adhesion, longer wear, smoother feel on the skin, appearance improvements and easier application
  • Process improvements include : easier dispersion, smoother pressings, reduced sebum absorption, more even blending and less moisture absorption
  • Surface treatments may include lauroyl lysine, ester coatings, lecithin, zinc or magnesium stearate, and even nylon or polyacrylates for enhanced skin feel


• Light diffusing particles
  
  
  • There are mainly used for an instant ‘wrinkle filling’ effect
  • Examples include barium sulfate, silica, mica coated with silica spheres, titanium dioxide, barium sulfate, aluminum hydroxide and polyethylene; to name a few
  • There are several varieties and more coming out constantly to provide consumers with an instantly younger appearance
  • These substances do not fill the wrinkles so much as diffuse light while being transparent on the skin, to remove shadows that would normally fill wrinkles and give the appearance of depth

Be Prepared for Multiple Samples!

Find Suitable Pigment Grade for Your Cosmetics