Best way to restore leather bellows?

I'm sure this has been covered to death. My bellows don't have any holes, but the black leather patina is all but shot and various shades of white/grey/green.

What should I use to recoat it black? Permanent black marker? Shoe polish? plastic paint? Elastic polymer paint?

What do you use if you have a set of patent bellows that you'd like another 100 years life out of?

I'm wondering what I should use if I want to re-glue these back onto the standards. Superglue comes to mind, but I'm wondering if there is a light-seal glue (black glue?) or is this something which I just do by mixing glue with elastic paint?

On a 1937 AGFA Jsollette I have, I repaired light leaks on the inside of the leather bellows by applying screen printing ink (like used for T-shirts), then letting that cure in the sun. This gave me a flexible and opaque solution, which should last many years. The outside I simply used leather cleaner, something like you might use on jackets or gloves. Anyway, probably a few others will chime in with more ideas.

Ciao!

Gordon Moat Photography

That's a clever idea Gordon.

Would India ink do the same then?

The difference I found was that India Ink does not dry and stay flexible, and that it does not block light as effectively. I should add that I think this worked because there is a cloth backing behind (inside) the leather on my old AGFA. So the T-shirt screen printing ink (more like paint) will adhere to the cloth. Also, I repaired that bellows over four years ago, and still use this camera without any light leaks.

Ciao!

Gordon Moat Photography

Why not use a regular ol' penetrating leather dye... like shoe dye? Clean the leather first, then dye it, then apply a leather conditioner like Lexol.

Or, if you want a higher shine, you can apply a thin coat of Neat-Lac after the dye.

The bellows need to be 100% tightproof irrespective of the colour. Indian ink (Rotring, from an arts supplier) is very good. Then a quality liquid leather polish to keep it flexible.

I routinely need to spruce up old leather camera parts. I use Kiwi leather dye to get the color back. Liquid shoe polish gets mixed reviews for camera use. The feeling is that the liquid kind ultimately causes the leather to dry out. On bodies, I use paste wax shoe polish. That would be very hard to use on bellows, though.
For that, I generally use Lemon Pledge aerosol furniture polish. It has lots of waxes in it. Mink oil would also be good. A word of caution about Lexol. It is a good preservative if the leather is in good condition to start with. However, if the leather is really old and dried out, it can cause it to fall completely apart. I've had it happen more than once, which made me say some very bad words. For remounting your bellows, just about any glue that's compatible with the materials at hand will work well. If you're gluing leather to wood, a good carpenter's wood glue will be fine. If it has shiny places when done, you can touch them up ith a little flat black paint. The glue does not have to be black. Whatever you use, please, please don't use silicone. I cringe every time I hear that word.