Below is a reply I wrote on another thread. I copied and pasted it here, because I didn't want to have to type it all up again!
There are two types of colorants: pigments and dyes. Dyes are usually in liquid format. They color by staining the actual molecules that they are mixed with. For these reasons, they are usually easier to use and incorporate into your products than pigments, but they can be more unstable (they can fade and bleed). Pigments are often in powder format. They do not actually stain the molecules. Instead, they just break down and disperse throughout the mixture, but do not absorb into the individual molecules. For these reasons, they are harder to use and incorporate into your products, but they are much more stable (do not fade or bleed). Both pigments and dyes can be either natural or synthetic, depending on where they are sourced (and on what your definition of "natural" is). Here are some of the various types of pigments and dyes.
Dyes Lab Colors - These are dyes carried by Bramble Berry specially formulated to be used in soaps and other bath products. They are better quality than food coloring. They are the easiest of colorants to use and very concentrated; just pour/drop your desired amount into your bath product, they incorporate very well. They are water-based. As their name suggests, they are made in a lab/factory, and therefore are synthetic and not natural. Because they are manufactured in this way, there is a huge variety and selection of every kind of color you can imagine, another pro in their favor. But because they are dyes, they can fade with time and sun exposure. They will also "bleed", meaning they migrate throughout your soap as it sits. This is no problem if your bar is all one color, but if you have mixed colors, say red and white layers, you will end up with red and pink layers. This effect can be used creatively, though, such as if you want to achieve an ombre look. You can get just about any color with Lab Colors, including bright and neon colors.
Food coloring - Food coloring is less than desirable for use in bath products. They have basically the same properties as Lab Colors, only are a lower quality and will probably fade sooner. Still, it is possible to use them.
LaBombe colorants - These dyes are specially formulated for use in bath bombes. They are oil-based instead of water-based, so that they won't set off the bath bombes' fizzing reaction early. Other than this, they are pretty much identical to Lab Colors in every other aspect.
Natural dyes - These would be mostly plant-based dyes, obtained by steeping plant parts such as seeds, roots, or flowers in oils or hot water to extract the natural color from them. An example would be annatto seeds, from which you can obtain a yellow color or orange color, depending on how long you steep the seeds. Plant-based dyes have all the characteristics of other dyes, (easy to use, incorporate well, can bleed and fade) except that they are natural and there is much less variety of color.
Pigments Oxides and ultramarines - Oxides and ultramarines are mineral-type pigments. They used to be mined from the earth, but are now manufactured in labs due to the presence of toxins in the mined sources. Whether or not they are considered natural depends on the individual's definition of "natural". Oxides and ultramarines are made identical to the natural sources (without the toxins, of course), which is why they are sometimes considered natural. However, they are manufactured in labs, and some have artificial colorants added to them to enhance their color, which is why they are sometimes considered unnatural. Whatever the case, oxides and ultramarines are stable in bath products, so they do not bleed or fade. They are more difficult to incorporate, however. It is sometimes helpful to mix them with a little water, oil, or glycerin before adding them to your soap. They mix in easier this way. The more natural oxides and ultramarines generally come in earthy tones and shades, while the ones enhanced with artificial colorants can be brighter. There are much fewer color options with these, though still a good variety. Oxides tend to mix easier with oil, while ultramarines incorporate better into water.
Micas - Micas are a very unique colorant, composed of double-sided mineral plates, each plate being almost two different shades of color, one on each side. Because of this structure, mica reflects light, causing a beautiful shimmer and shine to your soaps. Micas are manufactured in labs and many are colored with artificial colorants, so most are not very natural. Some may be considered natural, such as those coated with oxides or ultramarines. Again, it all depends on your definition of natural. Micas are more difficult to use than dyes, but easier than oxides and ultramarines. Micas, too, will incorporate easier if mixed with a little water, oil, or glycerin first. They are more stable and less likely to bleed or fade. There is less variety of micas than Lab Colors.
Natural pigments - Like natural dyes, and unlike some oxides and ultramarines, these are truly natural. Other than that there is less variety, natural pigments have the same properties as other pigments. Activated charcoal, kelp powder, and orange or lemon powder are examples.
Other colorants Color blocks - Color blocks for soap are blocks of melt and pour soap that have already been colored with either dyes or pigments. Especially for pigments, they make colorant incorporation much easier. They are usually concentrated. Depending on whether they are colored with dyes or pigments, they can be stable or unstable, natural or unnatural, bleeding or non-bleeding. There is a good variety, due to the fact that any color can be made into a color block. One disadvantage is that you may have to add a lot of the color block to achieve your desired color.
Clays - Clays can be considered natural colorants though not always as some are colored with oxides and ultramarines. Clays come in very earthy tones. They are stable in bath products, non-bleeding, and non-fading. There is less variety, and like other pigments, they are more difficult to use. However, the use of clays goes beyond just their color contributions. They are often used in face soaps for oily or acne-prone skin as they naturally absorb oils. They have more of a therapeutic use than all other colorants.
Non-bleeding colorants - These are liquid colorants, mixtures of pigments with, usually, glycerin. Since they are pre-mixed with glycerin, they have the ease of use of Lab Colors, but are non-fading/bleeding.
Titanium dioxide - This is a very helpful white oxide to have on hand. It is used to turn any clear soap to opaque white, or slightly opaque, and to make dark or vibrant colors lighter or pastel. It will not turn a colored soap white; it will only make the color lighter.
Vanilla color stabilizer - This is used in soaps in accordance with fragrance oils containing vanillin that are likely to discolor the soap brown. The vanilla color stabilizer keeps the soap white or cream-colored.
The one thing I am not sure about is the solubility of pigments. I have heard that oxides are more soluble in oil, and ultramarines are more soluble in water, but then I have also read that technically neither one is soluble in anything, because they do not actually absorb into the molecules, but just remain mixed throughout the solution. Anyone know more about this?
Hope this helps!
_________________ Olivia :)
Last edited by StokedTopHat on Mon Apr 21, 2014 7:09 pm, edited 1 time in total.
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