Two bottles of leather dye and dyed strips of vegetable-tanned leather on a wooden workbench.
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Spirit Dye or Oil Dye

ByPeter Joeseph 'Briefcase Maker' Kalafatis

Two names on the shelf that sound like opposites, and one safety sheet that says otherwise.

Spirit dye and oil dye sit next to each other in every leather supply catalogue, and the names promise two different animals: one thin and sharp, the other rich and slow. I hand-dye vegetable-tanned leather, and there is a video on my channel of dyeing a punk rock handbag where the colour was the whole point. I have dyed veg-tan in more than black, streaked blue and tan among them, so the bottle question isn’t theory on my bench. I’ll make the case for each one the way the sellers make it. Then I’ll read the label out loud, because the label says something the names don’t.

Video: How To Hand Dye Vegetable Tanned Leather for a Punkrock Handbag, from Marcellino NY Briefcase Maker on YouTube.

What the two names mean

Spirit is old shop talk for alcohol. Oil is a sales word that stuck.

Gloved hands bending a dyed leather strap to check the grain for cracks after spirit dye or oil dye.

Start with the spirit side, because it’s the simpler one. A spirit dye carries its colour in alcohol. The dye notes published by J. Hewit & Sons, a British leather supplier, describe Fiebing’s spirit leather dyes as coming ready mixed and say methylated spirits work as the solvent, with IMS or isopropanol as alternatives. In the United States the same bottle goes by a plainer name. Fiebing’s calls its Leather Dye a penetrating, alcohol-based dye, and claims the colour soaks into the fibre and “doesn’t simply paint the surface.”

The oil side comes from the same company. Fiebing’s sold a product called Professional Oil Dye, and the bottle now on the shelf is Pro Dye, which the maker calls “An improved version of our traditional Leather Dye.” Forum members on Leatherworker.net say the two names cover the same formula. Weaver Leather Supply files it under oil. Its guide to the different types of leather dye puts Pro Dye in the oil-dye column and Leather Dye in the alcohol column, then sets water-based LeatherColors off to one side as a third choice.

So the fight, as most beginners hear it, is spirit against oil. Thin against rich. One that dries the leather against one that feeds it. That’s the version I’ll argue first.

The case for oil dye

Softer hand, steadier colour, less cracking, according to the people who sell both.

Weaver doesn’t hedge. Its dye guide says “Alcohol dyes are harsher on leather and can also leave leather feeling stiff.” It credits oil dye with a softer finish that asks for less upkeep, colour that holds its tone over time, and less risk of cracking than the alcohol dye. It adds that Pro Dye wicks deeper on the flesh side than the other options, and that dipping beats daubers with an oil dye. Fiebing’s own Leather Dye page agrees on colour: it calls Pro Dye more colourfast, more vivid and less likely to fade in sunlight.

The people who use it say much the same, though forum posts are testimony, not testing. In a 2019 thread titled Pro Dye vs Leather Dye once and for all, one member wrote that Pro Dye “doesn’t dry out the leather and stiffen it like the other dye does.” In the same oil-dye thread, a member said Pro Dye dries the leather less than the standard Leather Dye.

For a strap, that matters. A strap bends at the buckle a thousand times. A handle wraps around a fist. Weaver’s guide to dyeing veg-tan also recommends Pro Dye where rub-off is the worry, which is every handle ever made, because the colour that comes off ends up on a shirt cuff.

My opinion: if the piece flexes and gets held, the case for oil dye is the stronger case. It looks like the grown-up bottle.

The case for spirit dye

More colours, easier mixing, lower price, and a long record in the trade.

Macro of the flesh side of a leather strap half oiled with neatsfoot oil and half left dry.

Now the other side, and it isn’t weak. Fiebing’s lists 29 colours of Leather Dye against the 21 listed on its Pro Dye page. If you want a shade the catalogue doesn’t print, the Leather Dye page says the colours mix into middle tones, and that a dye reducer thins both dyes to lighten any colour. In its own testing, Fiebing’s says, standard Leather Dye mixes with neatsfoot oil better than Professional Oil Dye does. Remember that line. It comes back.

Price sits on the spirit side too, by a little. Weaver’s beginner page lists Fiebing’s Leather Dye at $6.99 for 4 ounces; its Pro Dye listing starts at $8.99. That’s a sandwich, not a mortgage, but on a bench that runs through bottles the gap adds up.

Some makers simply like the way it handles. In a 2010 thread called Spirit Dye or Oil Dye, one member found spirit dyes too bright and cut them with alcohol, roughly half and half. Another found them too watery. Same bottle, opposite complaint, which tells you more about hands than about dye.

My opinion: spirit dye is the better bottle for anybody who mixes colour, and for flat pieces that never bend much, like a panel that lives inside a frame of stitching. On some of my hand-dyed veg-tan the edge gets dyed, burnished lightly and left without paint. On an edge like that the dye only has to sit under the burnish and stay put.

So that’s the debate as it’s usually told. Oil for flex and colourfastness. Spirit for colour range and mixing. I could stop here and you’d have a fair buyer’s answer.

Reading the label instead of the name

The safety data sheet for the oil dye lists alcohol first and oil nowhere.

Here’s where the argument eats itself. Weaver’s own product page for Fiebing’s Pro Dye says the product is sometimes called oil dye because of oils in the colourants, but that “the base of the dye is a solvent like standard leather dye.” The same store that files Pro Dye under oil in one guide says, on the product page, that it rides on solvent.

The safety data sheet for Fiebing’s Pro Dye in black settles it. Ethanol makes up 30 to 60 percent. A glycol ether makes up 10 to 30. Xylene and ethyl acetate run 5 to 10 percent each, with isopropanol behind them. The only ingredient on the list that a person would call oily is oleic acid, a fatty acid, at 5 to 10 percent. The sheet classes the dye as a highly flammable liquid under the signal word DANGER, and calls for butyl rubber or Viton gloves, tight goggles where it can splash, and ventilation. Even the Fiebing’s product page contradicts itself, calling Pro Dye solvent-based in one place and alcohol-based in the next. The UK retailer Abbey England sells the same bottle as a Premium alcohol‑based leather dye and marks it flammable.

Back on the 2010 forum thread, one member checked the pamphlet and took back his claim that oil dye cleans up with water. Another wrote that the two dyes “both in fact require alcohol/spirits to thin, clean, etc.”

So the spirit-versus-oil fight I just laid out is mostly a fight between two alcohol dyes. One carries a share of fatty acid and a pigment package that the makers say holds better. The other is the older recipe. Both will dry a hide if you pour them on heavy. Both want the window open. The name on the cap is a family nickname, not a chemistry lesson.

That doesn’t erase the differences Weaver and Fiebing’s describe. A tenth of the bottle can change how a strap bends. But it changes the question a beginner should be asking, and it’s not the question on the label.

Where the oil in oil dye really comes from

From a separate can, put on by the maker, before or after the colour.

Finished hand-dyed leather strap with burnished edges beside a tin of beef tallow and a buffing cloth.

If alcohol brings the stiffness, fat takes it out, and the makers who don’t crack straps put that fat there on purpose. Weaver’s veg-tan guide says to lay on a light coat of neatsfoot oil before dyeing. The Tandy Leather dyeing guide adds the finishing side: thin layers rather than a flood, buff until a dry cloth comes away clean, then seal.

The failure is on record too. In a 2009 thread about cracked leather after oil dye, a maker described a throatlatch strap dyed heavy on both sides with oil dye thinned in denatured alcohol, sealed twice, never oiled. It dried hard and the grain cracked when it bent. The advice that came back was oil, lightly, after the dye, and a night for it to soak in before the top coat. Another member mixed his dye straight into a conditioner. In the drying-out thread, one maker oils before dyeing, another oils after and conditions last. Nobody agrees on the order. Everybody agrees on the oil.

That’s also how the tanneries do it, only bigger. My Leather Choices page describes Hermann Oak’s black drum-dyed harness leather, immersed in dye and tumbled in drums stuffed with heavy tallows. The colour and the fat go in together. No bottle on a hobby shelf does that. On my own bench, warmed beef tallow goes into finished veg-tan, and I’ve written about tallow on dry vegetable-tanned leather before. My channel has a video on adding oil to natural veg-tan. Neither one is a dye step. Both are the part the oil-dye label takes credit for.

So here’s my opinion, and it cuts against the argument I opened with. Pick by colour and by how the piece will move. Oil dye for the strap and the handle, where Weaver and Fiebing’s both say it holds colour better. Spirit dye for a mixed shade. Then stop trusting either name to keep the leather soft, because neither one will. The oil is a separate can, and the can is your job.

For the colour choice itself, the piece on black, brown or cognac for work is a better place to start than any dye chart, and the earlier walkthrough on hand-dyeing veg-tan black covers prep, coats and sealing. A tenth of a bottle is oleic acid. The rest of the softness lives in your hands, a rag and a can of oil that never had a dye in it.

Fiebing’s Pro Dye, Black, 4 fl oz: An alcohol-based leather dye in black. See it on Amazon (affiliate link).

30-Pack Wool Dauber Brushes with Metal Handles: A 30-pack of wool dauber brushes with metal handles for applying leather dye. See it on Amazon (affiliate link).

Pure Neatsfoot Oil, 8 oz: An 8 oz bottle of pure neatsfoot oil for leather. See it on Amazon (affiliate link).

Leather Conditioner with Grass-Fed Beef Tallow and Lanolin: A leather conditioner made with grass-fed beef tallow and lanolin. See it on Amazon (affiliate link).

Fiebing’s Leather Deglazer, 4 fl oz: A 4 fl oz deglazer used to prepare finished leather for dye. See it on Amazon (affiliate link).

As an Amazon Associate I earn from qualifying purchases. A commission may be earned if you buy through this link, at no extra cost to you.

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