Wednesday, August 12, 2009

Mineral make-up ingredients: The oil absorbers - Calcium carbonate and starches

More pictures of white powders! I mean really, can you tell anything from them? In this picture, if you look closely at the lower left hand side, you can see a little bit has been crushed and there's a white residue. If you did this with something like titanium dioxide, there'd be a lot of white residue. If you did this with sericite mica, there'd be little to none. So I guess they are useful illustrations!

In anticipation of the post on creating a medium to high coverage foundation, I bring you a few ingredients I like to use in my foundations...

Calcium carbonate, or precipitated chalk, is an excellent addition to mineral make-up products for those of us with really oily skin. As I've noted previously, oils from your face can cause your colours to morph over the course of the day, and because it's alkaline, calcium carbonate is an excellent oil absorber, which is one of the reasons I include it in all the powders I make for my face - finishing powder, foundation, blush, and so on. It offers a matte finish and moderate coverage. It can, however, feel really dry and powdery if used in too high an amount, so I like to keep it at no more than 3%. It can be used up to 15%, but I advise against it because it ruins the skin feel.

When you think of chalk, you think of milky whiteness - this product is white, but not like that. It definitely adds some white to your products, but we're only using a little bit so it won't show up really white and chalky on your face. (In the finishing powder, I use about 3% and it doesn't add any whiteness when combined with the Micronaspheres and sericite mica, both of which are invisible). If you want to have a more white base, you can add it up to 15% and a very whitening foundation or blush. (If you have any adolescent goths running around your house, try this - it's two great products in one. It will make them look all pale and wan, and it will help control oily skin!)

Please note: Calcium carbonate is not approved for usage in lip products in Japan. (I have no idea why this might be...)

Usage: up to 15%, but I don't recommend more than 3%

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
It is white, but we use it at such low amounts, it doesn't have a huge impact on the colours. It is good for moderate coverage.

Translucency: The base itself is almost invisible once applied.
It's not going to be invisible on your skin if you use it at higher levels.

Skin protection
It does not offer skin protecting qualities.

Slip: The product feels nice going on and staying on.
Calcium carbonate adds some drag to your product, offering a powdery feeling instead of a silky feeling.

Adhesion: The product remains on your skin.
Good adhesion.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
Excellent absorbency and excellent colour retention for people with normal, oily, or darker skin. This is where calcium carbonate excels and is really the main reason to include it. In a finishing powder without colour, it will help to keep your skin from getting too shiny.

Light scattering properties: To give your skin a dewy glow.
Calcium carbonate offers a matte finish, so no dewy glow if you're using it in high amounts (10 to 15%). It won't have much an effect on the light scattering properties of a product used at lower levels (like 3%).

I really like using Dry-Flo in my mineral make-up products. With spherical particles, it acts a bit like the Micronaspheres in offering a silky feeling upon application and on your skin. It's a great addition because it can boost you from a light to medium coverage, and it offers a "peach like bloom" to the skin (which is, apparently, a good thing).

Unmodified starches like rice, corn, or tapioca starch do offer a lovely silky, smooth feel, but they can clump when exposed to moisture (and if you're including something like a hydrolyzed silk powder, you're attracting moisture with the humectant) and can cling to facial hair. We like them to absorb moisture and perspiration throughout the day when we're using them as body powders, but this isn't necessarily a good thing on our faces.

Unmodified starches are inexpensive - I know corn starch and tapioca starch are so cheap, I wonder how the manufacturers are making money - and they are available in most shops, so they're a great addition to your mineral make-up ingredients. Both can have a weird feeling - I know sometimes corn starch feels like it squeaks when I press on it (is this just me?), but I'm not going to get that in my mineral make-up!

Modified starches are more expensive - $7.00 a pound vs. $1 or $2 a pound - but they will eliminate some of the problems found with unmodified starches. You'll still keep the smooth feeling and peach like bloom (still not sure what this means!) without the clumping.

Both modified and unmodified starches are fantastic absorbers of oil, and they will help to keep your colours true throughout the day.

One note about starches - they are botanical in nature, so they can be an ideal place for microbial growth. So you'll want to note your products have a shelf life of no more than six months. Unmodified starches are definitely unpreserved; some modified starches are preserved, so check the label.

Usage: Up to 20%

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
Light to medium coverage, so it is going to offer some opacity.

Translucency: The base itself is almost invisible once applied.
It's not going to add much whitening to your product - Dry-flo will leave a little white behind, so it's not completely translucent.

Skin protection
It does not offer skin protecting qualities, except in the sense it can absorb moisture, which is a good thing to prevent chafing and itching when you sweat if you're using the starches in body powders.

Slip: The product feels nice going on and staying on.
It feels very silky on application and on your skin.

Adhesion: The product remains on your skin.
Good adhesion.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
Excellent absorbency and excellent colour retention for all skin types. It will also keep your skin from getting really shiny in an uncoloured finishing powder.

Light scattering properties: To give your skin a dewy glow.
Offers a "peach like bloom" to your skin.

Join me tomorrow to learn how to include these ingredients in your medium to full coverage foundation!


Mich said...

Hi Susan,

Would it be advisable to add either antioxidants or preservatives to any mineral makeup with plant or protein ingredients?

Thanks for the super blog!

Susan Barclay-Nichols said...

Hi Mich. Anti-oxidants aren't going to do a thing in a mineral make-up application for the preservation as the ingredients shouldn't go rancid. You could add some preservative to it...but which one? I've seen Germall Plus listed as an option and I've seen Phenonip. I'm sure which is suitable...let me do some research and get back to you!

Caroline said...

As far as corn starch (& other starches used in mineral makeup), is it true that it can cause acne or contribute to it?Does whether it's preserved or not have any bearing on it?

Susan Barclay-Nichols said...

Hi Caroline. In all my readings, this didn't come up. In fact, I stay away from anything that might promote acne as I have very acne prone skin! I don't believe preservation would affect the comedogenicity of starches.

If you have some information, I'd love to read it. But as far as I can tell from my research, starches should not affect acne.

Caroline said...

That's good to hear! I've heard many people say that when cornstarch (b/c it's a food by-product) is used in cosmetics that it can clog pores, but then harbor bacteria within b/c it's a "food" (the bacteria has something to live off of). I've read differing opinions on it, but this is one of those things that if people say it enough, do we just begin to believe it? I'll continue to research, but thanks for sharing your findings!

Sandra said...

What particle size should the calcium carbonate be if it is to be used in mineral makeup? For example, foundations, eye shadows and finishing powders.

Thanks very much :-)

Susan Barclay-Nichols said...

Hi Sandra. You know, I've never checked the particle size, and I don't see it listed on either supplier's site! The stuff I use is very fine, so I would think the answer "very fine" is all I can offer! I'm sorry I can't be more helpful.

River P said...

Very interesting can anyone tell me where you can buy Calcium Carbonate? Would this be food grade if there is such a thing?

Susan Barclay-Nichols said...

Hi River P. I get mine from TKB Trading. Food grade? I'm not sure. Ask your supplier.

Out of curiosity - why food grade? What are you making?

Phoebe Corrigan said...

Is it ok to put pure calcium carbonate on your face? I make a homemade translucent powder with eggshells. I peel off the membrane, wash the egg shell, put it in the oven for a bit to kill all the bacteria then ground it up in a coffee grinder. It works great I'm just worried is it bad for my skin.
Would it clog up my pores
Give skin rash
Dry out my skin

Susan Barclay-Nichols said...

Hi Phoebe. As I mention in the post, it is okay to put pure calcium carbonate on your skin. I don't know if I would use egg shells, though. I don't think you could get them clean enough.

Kim said...

IF I make a loose powder, will it be absorbed into the skin? For example if I made an antioxidant powder, will that absorb or does it need to be in cream/lotion/liquid form?

Musical Houses said...

Hey Susan, I've been experimentally DIYing small batches of loose powder for my own personal use. Right now the powder consists of silica, talc, synthetic fluorogophite, boron nitride, mica, and iron oxides for colour. Sometimes I also add in other commercially available loose powders as a way to use up makeup I wouldn't otherwise use (eg loose powder foundation that's a bit too dark etc.) Because the powder is for my own personal use, it's literally "put ingredients in container and mix", and quite amateur.

Right now, I'm thinking at adding some skincare actives in my powder, as I've noticed a few of them come in powder form (eg vitamin c, niacinamide, and so on), and it seemed to me that it might be easy to incorporate them (just add some to my loose powder and mix), but I'm not sure if this is how these actives should be used, as usually the suggested use is to mix in the oil or water phase of a lotion/cream/etc.. Do you think this is advisable, would the actives still work when incorporated into a loose powder product, and is there anything else I should consider (eg I know that using Ascorbic acid in powder form is a bad idea due to oxidation and the pH)? Also, if this isn't a lousy idea, would there be any actives that may be amenable to being incorporated in a loose powder this way? I've seen some MMU brands use ascorbyl palmitate, Allantoin or tocopherol acetate in their loose powder foundations or setting powders. Do you think these could be incorporated into my loose powder?

Thanks and sorry for the long question! I love your blog and I'm making it my mission to read all your makeup and skincare chemistry posts! :)