I am an admin for a Facebook group dedicated to reviews of watercolor supplies, and several members recently asked for comparisons of brown watercolors. It prompted me to make a swatch chart of some of my favorite single-pigment browns. Many of these pigments are rare and all of them produce excellent mixes.
This is my chart of 15 paints that I swatched in a Pentalic Aqua Journal. Although it isn’t cotton paper, it performs well and has a lovely texture. They are swatched in no particular order. I took closeups of some of the most interesting colors and describe them below.

You’ll notice that several Roman Szmal Aquarius paints earned a place on my list. They have an impressive selection of earth tones and many of them use uncommon pigments. Roman Szmal quickly became my favorite brand for a number of reasons: the colors are clean and vibrant; the majority of their range is single-pigment; they offer several unique pigments; they use a honey binder which makes them creamy and smooth; and they are handmade in small batches.
Schmincke is also well-represented because the colors I chose can be used to recreate some of their Super Granulating paints. I’ll go into more detail about those below.

Above is Schmincke’s Mahogany Brown (PBr33). Based on my research, they are the only company that offers this pigment. It was previously called Walnut Brown, but that version was discontinued and replaced with the color you see here. Interestingly, Walnut Brown was a deeper brown with a cool bias.
If you like Schmincke’s Super Granulating series but don’t want to buy the sets, Mahogany Brown would be a good addition to your collection. It is used in many of the Super Granulating paints such as Deep Sea Violet, Galaxy Pink, Forest Green, and others. This paint has earned a spot in my main palette because I’ve been trying to recreate some of my favorite paints in the Super Granulating series. Its heavy granulation and pinkish-red hue produces lovely mixes.

Schmincke’s Mars Brown (PBr6) can also be a useful addition to your collection. It is also included in several of the Super Granulating paints such as Glacier Brown, Galaxy Brown, Tundra Violet, and others.

Roman Szmal’s Aquarius Brown (PBr11) is possibly my favorite brown. It is extremely granulating and adds character to any paint you mix it with. It is a clean, earthy brown that can be used for riverbanks, mountains, trees, and more.

These two Roman Szmal colors shown above were released in 2022. They are both rare pigments.
Manganese Brown (PY164) is a warm, deep brown that is opaque in masstone. The only other company I could find that offers this pigment is Mameri Blu in their Sepia.
Iron Chrome Brown (PBr29) is a cool, deep brown that is also opaque in masstone. It is particularly useful in mixing greys or indigos. Currently, Mijello Mission Gold is the only other company that offers this pigment in their Van Dyke Brown Deep. I’ve only seen one swatch of it, but it leans more black than brown.
Winsor and Newton released a limited edition version of each of these in 2016, but they would be difficult to find now. I checked the websites of major US art supply retailers and neither of these are available.

Roman Szmal’s Van Dyck Brown (shown above) is considered the genuine version of this color, as it is the old formula used by the Masters. The “N” in the pigment index number stands for “natural.” It is derived from surface soil that is rich in peat or found near a deposit of brown coal, according to Handprint. Essentially, you are painting with dirt which delights my inner child.
Because of its consistency, it doesn’t behave like synthetic watercolors. You need more paint on your brush to get good coverage and it doesn’t flow as well. It is also not lightfast, so it is best used in journals. I included a synthetic version of QoR’s Van Dyke Brown on my swatch sheet as a basis for comparison.
NOTE: NBr8 is not the same as PBr8, which is a synthetic pigment. Below, I have included a swatch of a paint that uses PBr8.

Winsor and Newton’s Gold Brown (PBk12) is perhaps the most fascinating color on this list. “PBk” is not an error – it really is a black pigment. The common name is “Iron Titanium Brown Spinel.” The pigment is manufactured by Ferro and according to their website, it is commonly used in plastics, coatings, and industrial items such as cement. I did research to try to learn why it is considered a black pigment, but I haven’t been able to dig up any info. If anyone knows more about this pigment, please let me know in the comments. I’m very curious!
The Winsor and Newton version was released as a limited-edition color in 2014 as part of their Desert Collection. It is likely very difficult (or impossible!) to find in stores and I have not seen this pigment offered by any other watercolor manufacturers. I was able to locate an online retailer called fineartstore.com that sells the pigment powder, however I’ve never ordered from them so I can’t vouch for the quality of their products. If you have the Winsor and Newton version, consider yourself lucky! And if you see it in a store, you should snatch it up!

Prodigal Sons Pigments has become my favorite small shop for handmade watercolors. It’s a one-man operation and he specializes in historical and rare pigments. He also offers some common pigments, like the one shown above. Their lovely Manganese Brown (PBr8) is similar in color to Roman Szmal’s natural Van Dyck Brown, but it is easier to use. As much as I love Roman Szmal, this paint is a better option if you are looking for a soil-brown color.
If you would like additional closeups or more details about the colors I didn’t specifically mention, drop a comment and I will update the post. I am working on a similar entry about my favorite reds, so stay tuned!