There are three main types of dyes used to dye leather: Aniline, Semi-Aniline, and Pigmented. These three types of dyes have unique characteristics, usages, and finishing options. The tanning industry in Europe clearly defines all of these different types of dye, but for some reason in North America you will often see these terms misused. Rather than bombarding you with all three in one post I will break them out and discuss each type of dye on their own.
Aniline is often see as the “best” type of leather you can buy. Often this is due to the fact that Aniline leather is the most expensive type of leather due to the quality of the hides required to make Aniline. Aniline used to refer to any dye that was a derived from Coal Tar. Today Aniline dye is recognized as any clear dye that is used to tan leather with. Technically as soon as any pigments are added to the dye the dye should no longer be refereed to as “pure aniline”.
The reason why Aniline leather is considered the “best” type of leather is that due to the clear nature of the dye any imperfections on the surface of the hide will be seen. So only the cleanest hides can be used to make Aniline leather. This greatly reduces the number of suitable hides a tannery can use to make Aniline leather and requires the tannery to sort the raw hides. This is where the confusion comes in with regards to “better” as the cleanliness of the hide doesn’t speak to the quality of the hide with regards to performance. A corrected, pigment dyed hide will actually out perform an aniline in most applications and will therefore be a “better” hide in those applications.
It is the transparency of the dye that draws people to Aniline leather. Aniline is the purest form of chromium tanned leather. The dye allows the natural grain and characteristics of the hide to shine through. On heavier grained hides you will see the grain change from the edge of the hide, where it is heaviest, to very smooth on the parts of the hide like the neck where the skin on the animal was the tightest. It is the variation in the grain that makes Aniline dyed leather so unique and sought after.
Most Aniline colour pallets should be fairly muted as there is no pigment in the dye to intensify the colour. Aniline leather is the nudest of the different types of leather and as a result does require more care. What this does mean, however, is that over time the leather will develop a lovely patina that pigments and a most semi-aniline hides won’t develop. Aniline leather tends to have the softest hand and offer the most luxurious options when it comes to leather.
The best applications for pure Aniline leather tend to be low traffic areas or environments where the leather will be properly cared for. The lack of pigment means that Aniline is far more susceptible to fading in sunlight and if left unprotected will stain and be more difficult to clean. You can use Aniline in most applications providing that you are aware of the limitations and understand how it will age and ware.