Vinegaroon dye coloring grey with blotches

[3ntin]

Good evening, I'm working on a medieval sword scabbard with wooden core. I am at the final stepsn and I need to dye it. I want it black and, to mantain historical accuracy, I chose vinegaroon which I made by myself following the tutorial here

only got a small part of the steel wool in contact with air, a little of rust has developed.

I dyed my piece. At first, leather became deep black and I was very satisfied...but the next day it turned grey, and had lots of blothces and spots with no colour. I tried adding more and more but no difference. Tried a light sanding, nothing.

The leather covering is made with 1.2 mm vegtan calfskin, which has been cased and glued to the wooden core. I used a bone folder to shape it and adhere to the wood, using hot hide glue; leather got burnished after the process. My guess is that the process closed the pores of the leather preventing the solution to penetrate...after a light sanding I noticed a better penetration but little change in colour. Pics attached: at the bottom the scabbard; the strip next to it is a piece of the same leather...this got a nice and even colour, but with a gray tone (which darkens a lot after applying some conditioner).

Will try also applying black tea to darken the colour on a scrap.

In the meantime, i'm preparing a new batch of vinegaroon using degreased iron wire pieces which have not the problem of floating, so no possibility of rusting.

Thanks a lot in advance!

[BlackDragon]

Just to be clear you tried to dye it after you glued it to the wood?

[dikman]

Try dying a piece of the leather before you do anything to it, this will tell you if it's the vinegaroon or something you're doing to the leather (highly likely).

[3ntin]

14 hours ago, BlackDragon said:

Just to be clear you tried to dye it after you glued it to the wood?

yes, that's what I did...

 

11 hours ago, dikman said:

Try dying a piece of the leather before you do anything to it, this will tell you if it's the vinegaroon or something you're doing to the leather (highly likely).

the strip above the scabbard is the same leather dyed with the same vinegaroon. It has a much more uniform colour (as expected) but still gray and not black...went better after a bit of conditioner. I also tried on a cowhide scrap which turned a nice black...

[BlackDragon]

Vinegaroon can be tricky, even on a piece of leather that you haven't done anything on. When you start adding things to the leather it becomes even worse.

The vinegaroon works with the tannins in the leather so one piece of leather may not react the same way another one does. Sometimes even if the leather comes from the same cow.

At this point the leather that's on that scabbard is the best you're going to get with vinegaroon. You'll have to use a commercial dye on it, like Fiebing's Pro, if you want to save it. 

You tried conditioner on the test piece of leather, try some neatsfoot oil if you have any or virgin olive oil see if that helps at all. This will usually deepen what you have.

When I want something black I tend to use vinegaroon as a base then add Pro dye to the leather. This way I use much less black dye and it prevents rub off.

Edited Tuesday at 01:20 PM by BlackDragon

[3ntin]

Haven't took a picture yet, but I managed to quite save it. I sanded everything with 500 grit sandpaper. Then I brewed a strong black tea and did a coat of tea, followed closely by a coat of vinegaroon, twice. The colour isn't perfectly uniform but I'm quite happy with it...now I guess oil will suffice to get a good black colour.

On 7/15/2025 at 3:18 PM, BlackDragon said:

When I want something black I tend to use vinegaroon as a base then add Pro dye to the leather. This way I use much less black dye and it prevents rub off.

Don't want to do that on this piece: the scababrd has been made using only period techniques (parchment lining, split wood, linen thread, hide glue...) and I want the colour to match everything.

Next batch of vinegaroon is brewing. As far as I understood, also leather type will affect the richness of the colour, isn't it?

[BlackDragon]

3 hours ago, 3ntin said:

Haven't took a picture yet, but I managed to quite save it. I sanded everything with 500 grit sandpaper. Then I brewed a strong black tea and did a coat of tea, followed closely by a coat of vinegaroon, twice. The colour isn't perfectly uniform but I'm quite happy with it...now I guess oil will suffice to get a good black colour.

Don't want to do that on this piece: the scababrd has been made using only period techniques (parchment lining, split wood, linen thread, hide glue...) and I want the colour to match everything.

Next batch of vinegaroon is brewing. As far as I understood, also leather type will affect the richness of the colour, isn't it?

Good going on getting it to take a desirable black color! Looking forward to the pics.

I totally understand wanting to be period correct. I used to frequent Ren Faires quite a bit and had a couple in depth characters. 

Vinegaroon only works with vegtan leathers as it's a chemical process between the tannins (from oak, chestnut bark, etc) and iron acetate. The more tannins the better the reaction. Vegtan leather can be most any animal.

Vinegaroon wont work on Chrometanned, English Bridle, Harness, or Latigo.