Creating a Water-Based Tint

You're looking to create a water-based tint similar to Uthai Thip. Based on the discussion, Uthai Thip traditionally uses water-soluble food coloring. Cosmetic colors can be broadly categorized into dyes (which dissolve in a solvent like water or oil) and pigments (which are solid particles that need to be dispersed in a base).

• Dyes: Like the color in Uthai Thip or Acid Red 52 (Direct Dyes), dyes dissolve completely in water, resulting in a transparent color that stains the skin. They are easy to mix into water-based formulas.
• Pigments: Like Iron Oxides, pigments are solid particles. They don't dissolve but need to be evenly spread or "dispersed" throughout the liquid. This gives a more opaque or semi-opaque color depending on the concentration. Powder pigments, even coated ones like Iron Oxides Red (Ultra-fine, Methicone-Coated), can be challenging to disperse smoothly and keep stable in a very high-water formula (like 98.4% water) without specific dispersing agents or high-shear mixing. They are typically used in foundations, blushes, or lipsticks where they are dispersed in oils, silicones, or thicker bases.

Your proposed formula using Iron Oxides Red (Ultra-fine, Coated) might be difficult to get a smooth, stable dispersion in such a high percentage of water. The pigment particles might settle over time.

Suitable Cosmetic Color Options

For a water-based tint that is easier to formulate and uses cosmetic-grade ingredients, consider these options:

1. WaterMix™ Red (Iron Oxides Red): This product is an Iron Oxides Red pigment that is already dispersed in water. This makes it much easier to incorporate into water-based formulas like lip tints. It provides the cosmetic-grade benefits of Iron Oxides in a format suitable for your desired product type.
2. Acid Red 52 (Direct Dyes): This is a cosmetic-grade water-soluble dye. It will dissolve completely in water, giving a transparent, staining effect similar in nature (though not necessarily in exact shade or performance) to the traditional Uthai Thip color.

Using cosmetic-grade ingredients like WaterMix™ Red (Iron Oxides Red) or Acid Red 52 (Direct Dyes) is recommended for skin application. Concerns about melasma are often related to sensitivity or specific ingredient interactions, but using ingredients approved for cosmetic use is a good practice.

In summary, while your Iron Oxides Red (Ultra-fine, Coated) is a cosmetic pigment, it's a powder that is hard to disperse in high water content. WaterMix™ Red (Iron Oxides Red) (a pre-dispersed liquid pigment) or Acid Red 52 (Direct Dyes) (a water-soluble dye) are likely more suitable and easier-to-use options for creating a water-based tint.