How Colorant INCI Names Map to CI Numbers on a Filing

Colorants are the one category where the "just use the INCI name" rule gets murky, because a lot of colorants have both an INCI name and a Colour Index, or CI, number, and they show up interchangeably depending on the ingredient and the region. If you've stared at an ingredient deck listing "CI 77891" and wondered whether that's the same thing as the titanium dioxide you bought from your supplier, you're not imagining the overlap.

Where CI numbers come from

The Colour Index is a numbering system originally built for the dye and pigment industry generally, not cosmetics specifically. Cosmetic regulations adopted it as a way to identify colorants precisely, since colorant chemistry can get complicated and a CI number pins down a specific pigment or dye more tightly than a generic descriptive name would.

INCI names, by contrast, are the standardized cosmetic ingredient naming system generally. For most colorants, the INCI name and a familiar CI number both exist and both point at the same substance.

Titanium Dioxide as the clearest example

Titanium Dioxide is a good one to anchor on because you'll see it written both ways:

• As Titanium Dioxide, its INCI name, in an ingredient list aimed at general readability.
• As CI 77891, its Colour Index number, especially in regulatory or technical documentation, or when it's functioning specifically as a colorant rather than, say, a UV filter or opacifying agent in a formula.

Same substance, same CAS number underneath, different label convention depending on context and function.

Why the same substance can wear two hats

Titanium dioxide is a useful example of something else too: it can function as a colorant in one product and as something else, like a physical UV filter, in a sunscreen formula. Since sunscreen is regulated as an OTC drug rather than a cosmetic, the labeling convention that applies can differ from what you'd use in a plain cosmetic colorant context. This is a good reminder that function matters, not just identity, when you're deciding how an ingredient should appear on a given filing.

A short mapping table

INCI Name	CI Number	Typical Function
Titanium Dioxide	CI 77891	White pigment, opacifier
Iron Oxides	CI 77491 / CI 77492 / CI 77499	Red, yellow, black pigments
Mica	Not typically CI-numbered	Shimmer/pearlescent base
Ultramarines	CI 77007	Blue pigment
Chromium Oxide Greens	CI 77288	Green pigment

Notice iron oxides carry three separate CI numbers depending on which oxide shade you're using. That's a common trap, since "iron oxide" as a casual supplier description can hide which specific CI-numbered pigment, or blend of them, is actually in your product.

Practical filing guidance

When you're mapping your formula for a notification, the safe approach is:

1. Confirm with your supplier which specific colorant, and which CI number if applicable, is in your batch.
2. List the INCI name as the primary identifier, since that's the standardized system your filing expects.
3. Keep the CI number on hand in your own records, since it's a more precise disambiguator if a colorant question ever comes up, and some formats expect it alongside the INCI name.
4. Don't assume "natural mica-based colorant" or a similar marketing description tells you everything, since these often have no CI number and instead map to their own INCI name directly.

Where people actually get stuck

The two recurring mistakes are treating a CI number as optional trivia rather than a real disambiguator, and assuming every colorant has one. Botanical or mineral colorants sometimes don't carry a CI number at all and are identified purely by INCI name. The rule isn't "every colorant needs a CI number," it's "check what your specific colorant is documented as, and don't guess."

If you're working through a formula with several colorants pulled from different suppliers, matching each one correctly to its INCI name and CAS number, and flagging where a CI number matters, is exactly the kind of detail work Cosmetic Comply handles as part of mapping your ingredient list before filing.