The most surprising part of this build is that the whole thing started as a mistake. The maker set out to make a dye and ended up with a thick lotion instead, which turned out to be a viscous, red paste rather than the runnier mix that was intended. Instead of scrapping it, the maker carried on and tested the accidental result, and found the final look interesting enough to share.
The paste itself came from a reddish powder mixed into a lotion base. For mixing, the maker used a hot plate magnetic stirrer labeled '79-1', which has separate controls for Temperature, Heat, Power and Speed. Clear protective gloves were worn throughout, which seems like a sensible precaution when working with a dye this saturated.
The application process is what stands out to me. The maker scooped a blob of the paste straight onto a strip of undyed tan leather, spread it across the surface by hand, and worked it out to an even coverage. A crumpled paper towel then buffed away the excess lotion, leaving the sample with a light reddish-brown finish.
The maker has said the formula is oil-based but has declined to share the recipe, wanting to avoid controversy, which is fair enough. The open question is whether this lotion dye would actually be useful for anything beyond experiments, and the maker is unsure about that too. For a happy accident, though, the test piece came out looking promising.