Best way to make brown leather black?

I bought a new saddle, which comes with a matching breast collar and bridle. They are all black with lime green. I found a hackamore noseband in our plethora of extra tack, but it is dark brown. It is basically the same hackamore I ride my boy in now, but it won't match. :(

My mom said to use black shoe polish, but wouldn't that come off?
What do you recommend to darken leather?

You can purchase black leather dye. Just follow the instructions. You won't have a problem.

Look up the recipe for vinegaroon. It can be applied only to veg tanned (oak) leather but once it's on it doesn't come off forever. If not, Tandy sells black spirit dye. Any shine has to be removed with acetone (paint dept.). Apply the dye, allow it to dry. Take it out in the sun and see where it didn't quite take. Wipe that spot again with acetone then reapply the dye. Again, let dry. Then use turpentine and a pile of soft rags and literally attempt to remove the dye. You are removing the excess. When you can barely get any more dye off, give it a good saddle soaping to help lubricate the leather. Messy? It sure can be.

That very much depends on how the leather's been tanned and also its quality. Because the skin holds the colour it tends to be locked-in, particularly to pit-tanned English leather, which is why it's often difficult to re-colour faded saddles (especially black).

It's a case of worth a try, but there are no guarantees it'll take.

I've dyed quite a few pieces of tack and the color has never come off. I use a dye that I got at a shoe repair store but I think Walmart carries it. The brand name is Kelly - I've also used Fiebings with great success.

The key that I've found is to prepare the leather carefully. You need to strip away any oils and dirt. Once you've applied the dye and allowed it to dry, then condition it. That's it.

It is better to go from light to dark in color, so going from brown to black should be easy. I've gone from light oil to a burgundy and from light oil to a very dark oil with no problems.