Why Did My Soap Color Fade?

Short answer: faded soap almost always comes back to the colorant or the light. Colorants that aren't made for cold process, like carmine, iron blue (ferric ferrocyanide), pure dyes and lakes, craft micas and most botanicals, break down in lye or fade in sunlight. After that, check how much colorant you used, whether you added titanium dioxide, whether the soap gelled, and whether soda ash is hiding the color. Where on the bar it faded, and when, will usually give it away.

Start with the colorant

A colorant that can't handle cold process is the single most common reason soap fades, so begin there.

Carmine fades out in lye

Carmine, which may be listed as cochineal, carminic acid, Natural Red 4 or CI 75470, colors a lot of cosmetic reds, pinks and purples. It comes from cochineal insects, so it isn't vegan, and it can't survive cold process pH. The color changes, leaving beige, tan or blue-gray behind, often within hours. None of Nurture's colorants contain carmine.

Iron blue breaks down to brown

Iron blue, also called Prussian blue, ferric ferrocyanide or CI 77510, gives many deep blue, navy and purple micas their color. It can't take alkaline soap: the blue fades out and leaves brown, rust or a murky green-brown behind. If a dark blue or purple faded to brown, check the label for ferric ferrocyanide or CI 77510.

Pure dyes and lakes don't work in cold process

Straight dye and lake powders don't hold up in lye. They change color, fade over the cure, and bleed into neighboring layers. Water-soluble dyes are a good fit for melt and pour, where there's no lye. Lakes are oil soluble, so they don't work in melt and pour either.

Resin and craft micas often fade

Inexpensive micas made for resin, nail art or melt and pour have never had to survive lye, and in cold process they often fade or shift. If the label doesn't say the colorant was tested for cold process soap, assume it wasn't.

Botanicals fade in lye and light

Most plant colorants, like spirulina, beet root, hibiscus, paprika, turmeric and annatto, fade through the cure and faster in sunlight. They're lovely for soft, natural color, but not for color that lasts. Indigo can land anywhere from green to blue and doesn't always hold. Clays and oxides are the most stable natural options, though their colors are soft and earthy.

Other things that fade color

Sunlight and bright lights fade soap

Once a bar is finished, light is the biggest threat to its color. Soap cured on a sunny windowsill or displayed under bright lights fades on the side facing the light while the inside and back stay bright. Pinks, purples, yellows and natural colorants go first. Cure and store soap somewhere cool and dark.

Too little colorant looks faded

Fresh soap is off-white, and a small amount of colorant can get lost in it. If a bar looked pale from the very first cut, it most likely just needed more color. Use the full recommended amount.

Titanium dioxide fades color

Many soapers add titanium dioxide to a color hoping to make it pop, but it does the opposite: it lightens the color toward pastel and makes it look washed out. Use it only when you actually want a pastel, and leave it out of any color you want bright or deep.

Skipping gel makes color look dull

Gel brings out deeper, brighter color. Ungelled soap looks paler, chalkier and more matte, which is easy to mistake for fading. A partial gel leaves a brighter center ringed by paler soap. Yellows and oranges show this the most.

Soda ash dulls the surface

A white, powdery film on top of the bar is soda ash. It sits on the surface and makes the color underneath look faded or chalky, especially on dark colors. Cut into the bar: if the inside is bright, it's ash, not fading. Spritzing the top with alcohol after pouring and covering the mold help prevent it, and steaming or planing removes it.

Colors lighten a little as soap cures

Freshly cut soap holds more water and usually looks deeper and glossier than it will later. As it dries over the first few weeks, colors lighten slightly. That's normal, so judge color after the cure rather than on cutting day.

Vanillin can make color look dull

Vanillin, in vanilla, bakery, gourmand, amber and many floral scents, browns soap over weeks. It doesn't take color away, but it muddies it, so a bright color can look dull or faded. Check the fragrance's discoloration note, choose one from our no acceleration, no discoloration fragrance oils, or use a vanilla color stabilizer.

Where did it fade?

The whole bar, inside and out, from the first cut: too little colorant, titanium dioxide, no gel, or a colorant that broke down in lye.
A blue or purple that faded to brown: iron blue (ferric ferrocyanide).
Only the side that faced a window or light: light fading.
Only the top, with a white or chalky film: soda ash.
The outer edge, with a brighter center: partial gel.
The whole bar slowly over weeks: a pure dye, botanical or craft mica fading, or vanillin muddying the color.
Slightly lighter everywhere after cure: normal drying.

When did you notice it?

Right away, while pouring or in the mold: carmine, iron blue, pure dyes and lakes, or craft micas reacting to lye.
When you cut it (1–2 days): too little colorant, titanium dioxide, gel and temperature, or soda ash on top.
During cure (the first few weeks): pure dyes and botanicals fading, vanillin muddying the color, or normal lightening as the bar dries.
After it was fully cured: light fading from sun or display lights.

How to fix it next batch

Use colorants built for cold process. Skip carmine, anything with ferric ferrocyanide or CI 77510, pure dyes and lakes, and resin or craft micas.
Use enough, and skip the white. Follow the recommended rate, and don't add titanium dioxide to colors you want bright. It fades them.
Pre-disperse. Blend about 1 teaspoon of colorant into 1 tablespoon of light oil (sweet almond, sunflower or fractionated coconut) until smooth.
Encourage gel. Insulate the mold or use a heating pad for a full, even gel.
Stop soda ash before it starts. Spritz the top with alcohol after pouring and cover the mold.
Choose low-vanillin fragrances. Use a fragrance with no discoloration for bright colors, or add a vanilla color stabilizer.
Cure in the dark. Keep curing and finished bars somewhere cool and dark, away from windows and bright lights.
Judge after cure. A slight lightening as the soap dries is normal.

Find your color

Every color fades and shifts in its own way. For causes and colorants specific to yours, see:

Want help figuring it out?

Send us photos of the faded bar, including the inside if you can, and tell us the colorant you used and where the soap cured. A Nurture color expert will tell you what faded it and how to keep the next batch bright. Send it to Color Rescue or email your photos to support@nurturehandmade.com.