What's the difference between dyed and undyed goat hair brushes? Which one should you buy?
Dyed goat hair brushes aren't as common as they once were. Hakuhodo moved from selling dyed goat to undyed goat brushes in 2016 and brands like Wayne Goss quickly followed suit with Rae Morris and NARS moving to synthetic fibres. Chikuhodo, Koyudo, Bisyodo, Mizuho and RMK still produce dyed goat hair brushes if you're in the market for some.
There are two main levels of dye which are commonly used on goat hair brushes. The first type yields a soft colour that is most readily available from Sonia G and Koyudo. This type of dye imparts a soft colouring that's closer to a stain than a traditional dye. Some Sonia G brushes are dyed brown or a tea colour while Koyudo offers some partially coloured items. These are gentle formulations and although it changes the hair fibre structure, it doesn't damage the hairs as much as black chemical dye. You can definitely buy soft dyed goat eyeshadow brushes. The brown dyed brushes from Sonia G are a testamant to that.
The second type of dye is far more common and less expensive. Black dyed brushes are typically used to create uniformity in hairs of lower quality and will texture the fibres with a glossy coating. Consequently, these black dyed fibres tend to pick up less powder or reduce drag on the skin but they'll also be rougher. Dyeing hair black also tends to dry out the fibres.
Finally, I want to quickly mention the Koyudo Kakishibuzome Series. These brushes are coloured using completely natural dyes. Kakishibu is an old traditional technique that relies on the oxidisation of tannins from persimmon fruits. Think of these as stains rather than dyes because it doesn't use an oxidant to set the colour. I had previously only ever seen this technique used to dye cloth and wood. My late grandmother possessed an ornamental wooden box dyed using this technique and what's interesting is that over time, the stain grew progressively darker. Kakishibu imparts a light colour on the white hairs that yields something that Koyudo have described as "not brown, not orange [but] like a nostalgic shade at dusk".
This post will compare dyed brushes against undyed goat hair brushes using eyeshadows.
The science of hair dye
Dyeing hair is something I have a lot of experience in because I dye my hair. Premature greying runs in my family and my siblings and I have been showing greys since high school. I wrote a whole series of articles on the science of hair dyes when I worked for a beauty magazine. During that period, I had the opportunity to interview scientists and chemists. I still have my notes from these interviews and have referred to them here. I was also subject to a few experiments testing out the differences between wash-out dye, semi-permanent dye and permanent dye.
I'll spare you the boring details and the story of the disastrous bleach job but the general gist is that permanent hair dyes work by using ammonia to break through the layers of the hair to penetrate the cuticle and into the cortex. To impart permanent colour to something, you must scoop out the insides in order to make room for the dye particles. Ammonia-free dyes exist but they don't work as effectively and can cause colour to bleed during washing or fade over time. After clearing out the inner layers of the hair, you flood the now 'empty' cuticle with a coupler that gives your colour of choice to the hair and then you combine it with an oxidant such as hydrogen peroxide. Chemical reactions occur and bada-bing, bada-boom, you're good to go.
Now, why am I taking you through this scientific crash course? It's to explain that dyeing hair will change the protein structure of the fibre. Ammonia opens up the insides of the hair shaft to allow dye to change the hair. The stronger the ammonia, the deeper the dye molecules will penetrate. The gentlest forms of hair dye tend to mix a combination of natural ingredients with a low alkaline ammonia but the more you strip and flood the insides, the more protein structures you'll alter. Using permanent dye requires the molecules to be small in order to sink deeper into the hair. High molecular weight products will sit on the surface of the hair and typically won't dye all hairs uniformly. These types of dyes are found in wash-out products whereas low molecular weight dyes can reach deep into the core of the hair shaft. A good hair dye will bind to the keratin (the structural proteins that hairs are made of) so it resists colour fading.
The end result is that dyed hair become thicker than undyed hair. Dyed hair is thicker because the dye both penetrates deep into the hair but also sits on the surface of the keratin. If you've ever seen hair under a microscope, you'll see that it looks like a series of scales. If your hair is shiny and glossy, then it means that you have uniform keratin scales where the proteins are packed close together. The process of dyeing hair roughs up these scales and the dye pigments sit both underneath and on top of the surface of the hair. These uniform keratin scales won't be as nicely uniform as they were pre-dye so dye fractionally damages these smooth, straight hairs. Over time, these hairs are more prone to breakage. Ergo, the dye adds viscosity or weight and thickness to each strand. One benefit of dyeing hair is that because it adds a coating onto the fibre, you can reduce skin drag since the hairs have already absorbed chemical product so it will soak up less of your skincare or underlying base. Dyed hair also doesn't stick as much to skin so you might have an easier time blending eyeshadows.
Which one should I buy?
Making the conscious decision to choose between an eyeshadow brush made from dyed goat hair or undyed goat hair should depend on how you answer two questions.
The first question is: What does your eyeshadow collection look like? If you own more cream eyeshadows, satins, shimmery shades or duochromes, then you'll definitely want to invest in undyed goat hair. Ideally you shouldn't use cream products with dyed goat hair. If you mostly own powder products, crumbly eyeshadows or metallics then you might want to consider a dyed goat brush.
The second question is: How much do you value pigmentation? If the answer is "very much so, I want to create a bold, pigmented eye look", then you'll want to buy an undyed goat hair brush. An undyed goat hair brush picks up more powder product from the pan and deposits more onto the eye. If you like to wet your eyeshadow with a spray such as MAC Fix+ then you should look to buy undyed goat brushes. On the other hand, a dyed brush applies mattes more evenly and diffuses product faster than an undyed goat brush because it simply doesn't pick up as much on the bristles in the first place. You can build up product using a dyed brush but you'll need to be willing to invest more time in your makeup application. The only exception is that brown dyed goat hair picks up more metallic pigments compared to undyed goat hair.
How an eyeshadow looks is all a matter of perspective. The same eyeshadow will look different depending on the curvature of a person's eyes but sometimes our own eyes deceive us. Lighting also significantly alters how something appears, especially on camera. The use of a beauty light tends to make shimmers, glitters and metallics pop more. All photos posted here have been taken indoors reliant on natural sunlight or will be otherwise specified.
Some of my swatches will look a little discoloured by my veins showing through the skin but I don't have enough eyelid space to demonstrate these differences (which are already very difficult to photograph in the first place) so my pasty arm will have to do. The purpose of these demonstrations is to show the differences in pigmentation and diffusement.
I had been painstakingly searching for dupes or close brush matches to create this blog post for some time but Sonia G released a limited edition collection in December 2020 called the Keyaki Set. It contained three of the eyeshadow brushes available from the permanent Sky Eye Set but the Keyaki set brushes were made from undyed goat hair. It's much easier to compare like for like.
Matte Eyeshadows
Here, I used the shade Velouria from the Pat McGrath Divine Rose palette. The matte formula from Pat McGrath is very soft and highly pigmented but the darker shades can be patchy or grab onto uneven skin. It's why I chose it for demonstration.
I dabbed twice into the pan and swiped once onto bare skin. Top to bottom: undyed goat, brown dyed goat, black dyed goat
Below, again, I tapped the brush twice into the eyeshadow pan and I swiped downwards in thrice. At the top, near my wrist, I dabbed the brush thrice. The brush swatches are undyed goat, brown goat, black goat from top to bottom.
After one swatch, the dyed brown goat hair looks the most even but after three swipes, it's clear that pigmentation is richest with the undyed goat hair. The undyed goat hair spreads the same amount of eyeshadow more evenly while the brown dyed goat had allowed the powder to concentrate at the head of the swatch. The brown dyed brush gives moderate coverage and a softer diffusion whereas the black dyed brush lays down the sheerest pigment.
L to R: Black dyed goat hair, Brown dyed goat hair, Undyed goat hair swatches of Xtreme Mahogany from Pat McGrath Divine Rose under artificial lighting.
Xtreme Mahogany is the more patchy or finicky matte shade of the palette. Undyed goat creates the most even blend whereas the brown dyed goat had trouble moving some of the product which can grab onto itself. Black dyed goat reveals just how patchy the Pat McGrath matte formula really is.
Below is an example of a palette that's easier to work with in the Huda Beauty Coral Obsessions palette. On the right of the picture, I've used the bottom right corner shimmer shade first with the white undyed goat hair, then with the dyed goat. It's obvious how much more pigmentation and pop you get with the dyed goat.
On the right of the image, I've applied the top right corner orange terracotta matte again with the undyed goat hair first then with the brown dyed goat with two swipes. The pigmentation is far richer using the white undyed goat.
Satin Eyeshadows
Above, I've used the centre shade from the Viseart Libertine palette named Boundless which is described as a "shimmering poppy with a semi-matte finish". It is a unique formula because it performs more like a very soft and creamy matte than a traditional satin. Nevertheless, there's visible sheen to it.
The camera is incapable of picking up what the human eye sees. Out of more than a dozen photos, the one above shows the pearly sheen best. The swatch on the left is from an undyed goat hair brush whereas the one on the right is from the dyed brush. The undyed brush buffed the sheen into the skin when I blended the shadow whereas the dyed brush has blended the eyeshadow more so it looks more blown out or diffused. Consequently, there's far less opalescence from the dyed hair application.
The first panel above shows the performance of the Rephr 15 on the top and the Sonia G Blender Pro on the bottom. It may not be very obvious but the top swatch is darker. The panel on the right hand side is the exact same image but rotated. Where the brushes are shown horizontally, I think it's clearer that the swatch on the far right side applied with an undyed goat brush is more pigmented than that applied using dyed goat hair.
Metallic Eyeshadows
I love foiled metallic eyeshadows. Part of me just lights up and goes "ooh, shiny!" I will apply a metallic shadow using a brown dyed eyeshadow brush nine out of ten times. The brown dyed goat gives enough texture to the hairs to pick up flaky product better. You can press harder into the pan using an undyed goat hair brush or dip twice but my preferred technique is to wiggle the brush gently into the pan to pick up product.
Here, I've gently wiggled the brush once into the shade Sable Bronze (brown dyed and undyed) and then into the flakier Love Lace (black dyed, brown dyed, undyed,) from the Pat McGrath Divine Rose palette.
Baked eyeshadows
I've chosen two rounded crease or blending brushes of roughly the same shape, size and density. The Rephr 15 is made from undyed goat hair and the Sonia G Blender Pro from dyed goat hair. Both brushes are very soft to the touch. The Rephr brush has only a tiny amount more density. I typically use these brushes without any product on them to diffuse my eyeshadow to a fade or to blend out a transition shade but for demonstration purposes, these are brush applications of the NARS Dual Intensity Eyeshadow in the shade Telesto.
The dyed goat brush applies baked eyeshadows more softly compared to the undyed goat hair. The white bristled brush also allows the gold shimmer reflects to pop more whereas much of it is diffused away by the dyed hairs.
Duochrome Eyeshadows
We're back to the Pat McGrath Divine Rose palette to swatch VR Rose Venus which is a golden rose pink duochrome shade. Here I've dabbed twice to mimic brush application on the eye.
Most people would use a finger to apply a duochrome but if you would prefer using a brush, here are the results.
The Pat McGrath duochromes are a baked eyeshadow so the results are the same as above. The undyed goat leaves the shimmer in the shadow while the dyed goat dulls it.
The top swatch was made using undyed goat hair and it brings out the golden shift the most. In person, the undyed goat hair creates the most sheen and brilliance. The middle swatch was made using a brown dyed goat brush and it picked up fractionally more product on the brush overall but far more base colour which dulls the shine of the gold reflect. The bottom swatch was made using dyed black hair which yields a pathetic result.
Cream Eyeshadows
Most people use a synthetic brush to apply a cream but I keep my synthetic brushes separate from my fude. Realistically, I rarely remember to reach for a synthetic so I go for an undyed goat hair brush. The majority of brush manufacturers advise against using dyed bristled brushes to apply creams but I'm going to do it. For science! I typically try not to but I have used dyed goat with cream products in the past. Sometimes everything else is already dirty and I don't wash my brushes often enough. I've swatched the potted Cream and Powder Eye Colour from Tom Ford in the shade Golden Peach.
The top swatch was made using the undyed Jumbo Blender and the bottom swatch with the dyed Jumbo Blender from Sonia G. There's just no comparison. The white undyed goat picks up product easily and gives you a sheen to the product. The undyed goat hair just fails to pick up as much product (and you don't need much of the Tom Ford cream in each application) and it ends up looking lacklustre.
Conclusion
The take away from this exercise is that undyed goat hair delivers the most intense pigmentation. Undyed hair will also maintain shimmer and shine in satin, baked and duochrome formulas. More blending time is required to soften harsh lines using an undyed goat hair brush. Undyed goat hair is best for cream products.
Dyed brown goat hair gives moderate pigmentation and applies product more smoothly if the brush is used in a directional swiping motion. On the blending front, it will very quickly soften harsh edges so if you don't mind sacrificing pigmentation for a faster blending experience, then brown dyed goat will suit you excellently. You can build up colour intensity but of course, it'll take more time. Dyed brown goat performs the best with metallic eyeshadows or anything that is crumbly in texture and will up more product from the get-go.
Black dyed goat hair will apply the least pigmentation. Just don't buy black dyed goat hair brushes to apply eyeshadow. There are reasons in favour of purchasing black dyed goat face brushes but don't waste your money investing in these eyeshadow brushes. You deserve better.
I hope this was interesting. I'm off to wash my arm and dunk it in a tub of moisturiser now.