Binders: Pressed face powder and eye shadow are extremely popular because they can be easily carried and applied. In order for a free-flowing powder to be pressed into cosmetic containers, a liquid binder has to be uniformly dispersed through it. Binders usually consist of powders such as zinc stearate or magnesium stearate or oils such as jojoba oil or fractionated coconut oil. Glycerin or alcohol may wet a product, but it will not bind them together. Glycerin may attract moisture from the air and contaminate your powder.

Certified Lot Number: This is the identifying number assigned to each batch of colorant by the FDA when a manufacturing company’s submitted batch is certified. It is unique to that color and that batch.

Hue: The hue or shade of color is described by using the color Index (CI) terminology. It is a method that was developed to standardize the verbal description of colors.

Safety: All the certified dyes listed for use in the US have been tested at least three times. “Safe” is determined by law as “convincing evidence that establishes with reasonable certainty that no harm will result from the intended use of the color additive.

The Color Index (CI): This is the best-known reference book on color, edited jointly by the Society of Dyers and colorists and the American Association of Textile Chemists and colorists. No matter what language one speaks, if the CI number is known, the chemical, structural, and physical properties of the colorant are available.

The Code of Federal Regulations (CFR): The CFR is the codification of the rules published in the Federal Register by the Executive branch and the agencies of the U.S. Federal Government. It is updated annually.
FD & C colors: for use in food, drug and cosmetics.
D&C colors: for use in drugs and cosmetics.

Ext. D&C Colors: Colors for use in externally applied drugs and cosmetics which do not come into contact with mucous membranes.

Colors
For the most part, the inorganic pigments, pearlescent pigments, and Lakes are what we will use and sell at Just Pigments. They are generally the safest and most approved colors for use in eye shadows, powders, blushes, mascara, and eyeliner. It is important that the pigments used are specially produced for cosmetics and purified with no heavy metals. They are also used for many other industrial purposes, such as paint, resin, polymer clay, and so on.

Dyes: colorants which are soluble in vehicles such as water, alcohol, glycerin, or oils.

Natural Dyes: Apart from purity considerations, natural dyes are widely used in foodstuffs. There is no restriction on the use of natural dyes in cosmetics. In general, natural dyes are not resistant to heat, light, and pH stability. This makes them much inferior to their synthetic counterparts. They should be thoroughly tested in finished products. In some instances, natural dyes exhibit strong odours. Just Pigments does not sell any colors for ingestion or natural pigments made from fruit, vegetables, or animals.

Pigments: Colorants which are insoluble in the vehicle in which they are used. They are generally referred to as “dispersible,” meaning they will mix with water or oil.

Acid Dyes: All water-soluble dyes are classified chemically as acid dyes. Acid dyes are usually the sodium salts of sulfonated or carboxylated dye molecules.

Solvent Dyes: The oil-soluble or non-polar dyes are those which have no salt-forming groups on the dye molecule. They will dissolve in hydrocarbons, oils, waxes, and aromatic solvents.

Pure Dye: This is the amount of dye actually contained in the certified colorant, exclusive of inorganic salts, moisture, side reaction products, or unreacted intermediates. 

The Effects of Particular Size
Different effects can be achieved by the right choice of pigment and particle size. Small particles (less than 15 microns) create silky and satin effects and will opacify the mass. Larger-sized particles (larger than 100 microns) create high-lustre effects, either sparkling or glittering, combined with high brilliance and transparency.
There are a few basic rules that we follow when formulating with pearl lustre pigments. 

Color EFFECT vs. PARTICLE SIZE
Particle Size 15 µm or less = low lustre, good hiding power
Particle Size 2-25 µm = silky lustre and strong hiding powder
Particle Size 10-60 µm = pearl lustre with medium hiding power
Particle Size 10-125 µm = shimmering lustre and low hiding power
Particle Size 20-150 µm = sparkling lustre and transparent
Particle Size 45-500 µm = glittering lustre and very transparent

MICA pigments with a particle size of over 150 µm are not permitted on the FACE in the US.

This information about particle size will come in handy when it comes time to make up your own recipes. If you are making a transparent powder, the less opacity the formulation has, the better your pearlescent effect will be. In these transparent powders, the amount of pigment is fairly low compared to the ratio of MICA and fillers.

Pearlescent pigments should never be ground with a mortar and pestle. By grinding them, you break or remove the metal oxide from the mica plates, which will result in a loss of lustre and a change in color. Pearl pigments are easy to mix into other ingredients and can always be mixed in at the end.

Oxides and lake pigments do not have a lustrous effect and are difficult to blend. Conventional oxides are very difficult to get properly dispersed without high-speed mixing equipment.