When you want to add a bit of colour to something, there’s a lot to consider. What colour do you want? Do you want opacity along with the colour? How long do you want the colour to last? What is the end use of the product? And let’s not forget the all-important solubility. I often get questions about using one colourant instead of another in recipes, so I thought I’d write an overview on the different types of colourants I use, why I choose them, and what they’re best suited for.
Colours available: More natural shades of brown, beige, green, pink, red, and white
Will they oxidize or fade? Not in my experience
Potency: Depends on the clay, but generally somewhere below oxides and above botanicals
I love clay, and I’ll add it to pretty much anything if given the opportunity for slip (in soap), cleansing, moisture management, and (of course) colour. There are a lot of different clays out there, but when we’re talking clay for colour we’re usually talking about Australian and French clays. They’re available in a variety of muted tones (with the outlier of crazy dark Australian Reef Red), and smooth and light, making them innocuous additions to many things (grittier clays like bentonite or rhassoul are generally not good clays to use as colourants unless you’re looking for something brown/grey and scrubby).
Something to keep in mind with clays is that their colour is prone to shifting when wet. If you’ve ever applied a clay face mask you’ll know what I’m talking about. For this reason clays are not generally suited to applications where they’ll go from wet to dry.
Another consideration with clays is the possible variation within the clay category. I’ve heard from several readers that the Australian Red Reef clay they’ve purchased for my Red Rose Lipstick is not the same colour as mine, and does not produce the same colour of lipstick. Whenever something is natural and not produced specifically for its colour, this is a concern. I’ve also found clays seem to have more variation in appearance depending on lighting.
I tend to use clays for colour mostly in soaps. Since I almost always add clay to my soaps it’s an easy way to add colour without any extra ingredients. Clays also hold their colour through saponification.
Other places I’ll use clays for colour is in cosmetics. I have several lipstick recipes that are powered entirely by blends of red/pink/beige clays, and they’re quite lovely. Because they’re in an oil base the clay doesn’t dry out and shift colours or go splotchy once applied. I’ve tried lip stain/lip gloss type applications with clays, but they end up drying out, powdering up, and looking (and feeling) terrible on the skin. And while you can make lipsticks with clay, I do find I prefer to make them with oxides and carmine—you can get much brighter colours, and a much wider range of them. You can also be guaranteed to get the same colour blend every time.
When I use clays in powders like blushes I find I always have to supplement the colour with oxides to get the colour concentration required, even if the clay used is an excellent match for the colour I want. Once it’s been mixed with other ingredients it’s just not strong enough to hold its own.
Colours available: Natural shades of brown, green, teal, black, red, green, and yellow
Will they oxidize or fade? No
Potency: Very potent, even in small amounts
Iron oxides are a fantastic arrow in your colour quiver. They are potent, consistent, insoluble, smooth, light, inexpensive, and reliable. They don’t fade over time, and they pack a serious colour punch in tiny amounts. They can be added to finished formulas that need just a hint of colour without effecting the final product.
Iron oxides occur naturally as what is basically rust, but heavy metal contamination is a concern. Therefore, the oxides we purchase are synthesized. They’re chemically identical to their naturally occurring cousins, but they don’t contain dangerous heavy metals.
I use oxides in a lot of recipes. They’re great in soaps because you only need a tiny amount, they hold true through saponification, and they don’t fade as the soap ages. They’re brilliant for tinting lip balms without effecting the texture of the final product. Where they really shine, though, is in cosmetics of all varieties.
The potency of oxides simply cannot be replaced in cosmetics. For anything that contains titanium dioxide, zinc oxide, and/or sericite mica (USA / Canada), you need the potency of oxides to get yourself a final product that isn’t mostly white. The stability of oxides is also a must-have, as I don’t know anybody who likes discovering their carefully colour-matched concealer is a completely different colour a week or so after making it. And because oxides are the same colour every time you buy a jar, you can rest assured that your carefully blended colour formulations will hold true over time.
Colours available: Vibrant shades like cobalt blue and bright lavender
Will they oxidize or fade? No
Potency: Very potent, even in small amounts
Ultramarines are pretty much the same as oxides when it comes to how we use them, they are just synthesized from different ingredients. The blue is the synthetic version of lapis lazuli, a very expensive semi-precious stone from Afganistan that used to be our sole source of bright blue pigment. We figured out how to synthesize it in the early 1820’s, and now ultramarines are synthesized from ingredients like sulfur, clay, and charcoal. The bright blue pigment is irreplaceable (without using FD&C dyes) and is fantastic in blends with carmine to create beautiful purple hues.
Colours available: All the colours of the rainbow
Will they oxidize or fade? No
Potency: Fairly low
Micas are fine, shimmery powders that pack a strong sparkly punch. They’re available in all the colours of the rainbow because they are coloured with oxides and FD&C dyes, so not all micas are all that natural (check the INCI of each colour/variety to see how it is pigmented).
I find micas offer a strong colour punch to the appearance of a product, like a tube of lip balm, but the colour isn’t strong enough to make much of a difference on the skin. I’ll usually pair them with some iron oxides if I want a strong colour to come through in the end product.
Dyes & Liquid Oils
Colours available: Varies, depending on how natural you want to keep things
Will they oxidize or fade? Varies
This is a category with a lot of variation.
If you’re ok with FD&C dyes you can get any colour of the rainbow and it’ll last forever. I’ve worked with a couple of the powdered FD&C dyes, and they work very much like iron oxides do. They’re insoluble, highly potent, and generally much brighter; an FD&C yellow will be a true, bright yellow while yellow iron oxide is browner and muddier. If you like super vibrant colours, they work really well.
New Directions Aromatics sells a few shades of natural liquid dyes. They’re derived from things like spinach and spices, and are water soluble. I’ve only tried the orange, and I’ve found it to be useful in CP soaps and lip stain. I have, however, noticed that it is a bit reminiscent of the paprika it’s derived from in the scent/taste department. I can’t speak for the other colours as I haven’t tried them, but you could find the green is a bit spinach-y. I’d recommend doing your research an reading the reviews before committing to anything.
For oils, the colours you’ll come across most often are greens and oranges. Raw hemp seed oil (USA / Canada) is quite green and will lend a green tint to lotions and body butters, but it isn’t strong enough to colour the skin. Buriti oil and seabuckthorn are two orange oils, with buriti being the strongest of the two. Buriti is so orange that it’s almost impossible to use as anything but a colourant–straight application to the skin will have you looking like a pumpkin quite promptly. I love using buriti oil in soap to get yellows and oranges (depending on how much I add). Seabuckthorn oil varies in strength (the berry oil is more potent than the seed oil), and can vary from giving an orange tint to balms and soaps to giving you an orange tint.
Solubility: Water soluble, oil dispersable
Colours available: Bright, vibrant red/pink
Will it oxidize or fade? No
Potency: Extremely strong
Carmine is amazing and completely irreplaceable in the natural world (FD&C Red No 7 is a fairly close colour match, but it is insoluble so you cannot use it anywhere we need carmine’s water solubility). It’s a bright pink/red and packs an exceptionally potent punch. Just a small amount of the powdered stuff mixed with some water and glycerin gives you an unbeatable lip and cheek stain. A few drops of the liquid dye gives you a beautiful tinted lip balm, and more can be added for a stronger tint. It is quite pricey by the gram, but it’s much lighter than the oxides, so in the end it’s not quite as awful as you get a larger volume for the price.
Now, carmine is not vegan—it’s made from the cochineal insect. If you’re vegan and/or grossed out by this (or can’t afford it), I’m afraid I can’t really offer you a natural alternative. In tinted lip balms you can use a bit of red iron oxide instead, but the colour won’t be quite as vibrant. I’m afraid you are out of luck for water soluble alternatives, though.
Botanicals (Beet root powder, rose hip extract, etc.)
Solubility: Water soluble
Colours available: Natural shades of red, pink, beige, brown, green, etc.
Will they oxidize or fade? Yes
I want to love botanicals for colourants, but they are pretty darn useless. They’re water soluble, but once mixed with water they oxidize quite rapidly, eventually leaving you with a brownish grey final product. They’re also not very potent, meaning you can’t really use them in anything that contains ingredients like titanium dioxide or sericite mica (USA / Canada). In soap they tend to dramatically shift colour during saponification, generally turning brown or black. The best uses I’ve found for botanicals as a colourant is in bath salts/ bath bombs as they’ll colour the dry product and then dissolve into nothing in the tub. You can also infuse them into oils and then strain out the solids. This will give you a nicely coloured oil (makes for nice tinted lip balms) that has fairly low colour transfer to the skin. Do watch out for scent/flavour transfer, though! I’d also recommend keeping these infused oils in formulations that don’t use any water to avoid oxidization.
Honestly, when it comes to botanicals I’d save your money. I haven’t found them to be hugely useful (or essential, at least) for much of anything.
This post was updated November 29, 2016.