The first step to any foundation is its base. There are three main kinds of liquid foundation bases: water, silicone, and oil, per Makeup.com. Foundation can also be powder-based, per Byrdie. Each comes with different properties and effects on the skin, so it is important to also understand your specific skin type to find your best foundation match, formula-wise. Foundations may also include a number of other ingredients that can be categorized as emulsifiers, pigments, emollients, and more, which each play a specific role in the overall effect of the foundation. For example, emulsifiers maintain the overall consistency of the formula, while emollients maintain the skin's moisture, per Beautylish.
Water-based foundations are known for being gentle on the skin, per Makeup.com. Often moisturizing and nourishing, water-based foundations can work well for those who have drier skin or breakouts, and those who seek a more natural finish to their makeup look. Now, it is important to note that water-based means just that, while the foundation's main binding agent will be water, it could still also contain other ingredients that would be categorized as oils or silicones.
