Colorants for Bath Bombs and Solid Bubble Bath

There is nothing like tossing a colorful bath bomb into your tub and watching as a rainbow of colors explode out of it as it dissolves! If you’ve been ooooohing and awwwwwwing over fizz videos but haven’t a clue how to get these bright and fun colors, this post is for you. Let’s talk about coloring your bath bombs and bubble bars!

(Note: This post is written based on U.S. FDA guidelines for cosmetic colorants. If you are outside of the U.S., check the cosmetic regulations where you live.)

Let’s start with what you CAN color bath bombs and bubble bars with. These products are considered cosmetics in the U.S., so the colorants added must be approved for cosmetic use by the FDA. Here is a handy chart that you can reference to research your colorants.

FDA – Color Additives Permitted for Use in Cosmetics

As you read through the chart, you’ll need to reference the Generally column. That is where bath bombs and bubble bars fall.

Here are four types of colorants that you can use to color your bath products. They are in order of my personal preference! I start with my favorite colorant type and end with my least favorite.

Dyes

Dyes are pure color pigment. They dissolve in water easily, coloring it bright colors. Since dyes dissolve, they don’t leave a residue in the tub and easily wash down the drain.

  • Dyes allowed or not allowed: There is a long list of dyes that can and cannot be used in cosmetics. Refer to this chart from the FDA and choose only dyes that say yes under the Generally column.
  • Dispersion: Dye powder easily dissolves into water. There is no need to use polysorbate 80 with dyes. However, I still recommend using polysorbate 80 to emulsify base oils and fragrant oils into your bath water.
  • Usage Rate: What you see is what you get when working with dyes. I start with 1/8 teaspoon – 1/4 teaspoon per 2 cups of baking soda and add more for a darker color.

Lakes

Lakes are insoluble color compounds created by precipitating a dye with a metallic salt. Even though the are made with dyes, lakes do not dissolve in water, they color water by dispersion of their particles (similar to mica).

  • Lakes allowed or not allowed: There is a long list of lakes that can and cannot be used in cosmetics. Refer to this chart from the FDA and choose only lakes that say yes under the Generally column.
  • Dispersion: Lakes color the bath water by suspension of particles. They do NOT dissolve. You’ll need to use polysorbate 80 so that the particles don’t stick to the oils in your tub.
  • Usage Rate: What you see is what you get when working with lakes. I start with 1/8 teaspoon – 1/4 teaspoon per 2 cups of baking soda and add more for a darker color.

Mica

Mica is what gives our products sparkle and shine. It is a mineral that is naturally mined from the earth. It comes in shades of cream to gray. Mica is then colored using lakes, dyes and mineral pigments to create the bright powder colorants that we are used to buying.

When deciding to use a mica or not in your cosmetic creations, you’ll need to take a look at the INCI (International Nomenclature Cosmetic Ingredient). If the ingredients listing for the mica contains colorants that aren’t allowed in cosmetics, then you can not use the mica.

Here are two examples:

Let’s take a look at two micas and their ingredients listing to see if they would be good for cosmetic products.

Brilliant Blue Mica from Nurture Soap (Mica, titanium dioxide, ultramarine blue) – This mica is colored using titanium dioxide, which is approved for cosmetics and ultramarine blue, which is NOT approved for cosmetics. You couldn’t use this colorant in bath bombs or bubble bars.

Cabaret Pink Purple Mica from Nurture Soap (Mica, titanium dioxide, manganese violet, iron oxide) – This mica is colored using titanium dioxide, manganese violet and iron oxide. All of the mineral pigments are approved for cosmetics. You can use this mica to color bath bombs and bubble bars.

  • Mica allowed: Mica colored using allowed mineral pigments, lakes and dyes
  • Mica NOT allowed: Mica colored using chromium hydroxide greens, chromium oxide greens and ultramarines
  • Dispersion: Mica colors the bath water by suspension of particles. It does NOT dissolve. You’ll need to use polysorbate 80 so that the particles don’t stick to the oils in your tub.
  • Usage Rate: What you see is what you get when working with mica. I start with 1/4 teaspoon – 1/2 teaspoon per 2 cups of baking soda and add more for a darker color.

Mineral Pigments

Mineral pigments include oxides and ultramarines. If you are a soapmaker, you probably have an arsenal of these types of colorants. They work well it soap and are quite stable. I don’t really like them in bath bombs and bubble bars because they can leave a mess in the tub, even when using polysorbate 80, but they are used to color mica, so it is important to know which are approved for cosmetics or not.

  • Mineral pigments allowed: iron oxides, manganese violet, zinc oxide and titanium dioxide
  • Mineral pigments NOT allowed: chromium hydroxide greens, chromium oxide greens and ultramarines
  • Dispersion: Mineral pigments color the bath water by suspension of particles. They do NOT dissolve. You’ll need to use polysorbate 80 so that the particles don’t stick to the oils in your tub.
  • My personal opinion: Mineral pigments can be quite messy in the tub and are harder to disperse using polysorbate 80 than other particle-dispersing colorants such as lakes and mica. I avoid straight mineral pigments, but do use mica that contains mineral pigments. Just my personal opinion!

Batch Certification

Dyes and lakes must be batch certified by the FDA to use in cosmetics. Most suppliers state if their colorants are batch certified or not. If they do not specify, be sure to ask. The label on certified colors must state the legal name for the color (such as “FD&C Yellow No. 5”), or, if it is a mixture, the name of each ingredient; the FDA lot certification number; and the color’s uses and restrictions. source

If they can’t provide you this information, move on to another supplier. Here is a list of suppliers that have requested color certification within the last two years.

Emulsifier (Polysorbate 80)

Many bath bomb and bubble bar makers are confused when it comes to knowing when to use polysorbate 80 in their formula.

Dyes are the only color additive that completely dissolve in water. All other color additives remain in particle form (they do not dissolve) and can cling to base oils and fragrant oils as you drain the tub, leaving the infamous colored ring. Because of this, it is recommend to use polysorbate 80 to emulsify these oils into your bath water. Then, when you let the water out, the color particles don’t have anything to stick to.

Technically, dyes dissolve and don’t cling to oil, but I recommend using polysorbate 80 to emulsify any oils into your bath water, no matter your colorant.

I personally get my colorants from Mad Micas and Nurture Soap, but there are tons of companies that sell colorants for cosmetics. Join our Facebook Group and under the files section, we have a list going!

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