I just read a question on this at another site. Advice was given on how to match the old finish.

Here it is:

Here is a link that might be useful: Matching Old Finish

Good link, bookmarked. Thanks for sharing.

I would strip them in a heartbeat. In fact, I did many doors sort of similar (ca. 1910,dark mahogany/rosewood stain over birch veneer, glazed and six-panel) for a customer. I removed the paint with a heat gun and stripped the residue with Kutzit (my standard procedure when there is old varnish underneath).
The polished dark doors and light trim give a very classic, rich look IMO.
The original stain was probably a combination of dyes and pigment, to secure the very deep color. You can duplicate this today with a base coat of dark mahogany aniline and an over-stain of merlot+java oil gel stain, or you can get a slightly lighter color by using just the merlot, followed by the java,which gives a very nice antiqued effect.
For a finish, nothing is better than a few coats of Garnet shellac, topped by whatever you prefer: many coats of clear, dewaxed shellac, a coat of wipe-on satin poly, or a coat or two of water-clear restoration varnish, of the old slow-drying poly-free variety.
I'd disregard the advice on the other site that claimed that shellac was inappropriate and never used for woodwork because it got cloudy. That results from the ignorant use of wax-bearing commercial canned shellac, which shouldn't be used for anything but maybe boyscout projects. Dewaxed shellac is extremely durable and never changes color. All shellacs have the benefit of being safely removed without harmful stripping chemicals.
Casey

ColumbusGuy, thanks for the link, and Casey, thanks for your input; you always have good advice.

I'm going to try these doors. If they look good, we have pocket doors in our dining room that never got painted because they were stuck in the walls for decades. The first repair we had done on this house (after refinishing the floors) was having those pocket doors fixed. They are dark, unpainted, but the finish is shot. Maybe I'll do those second!

Casey, could you post some pics of the results of your two recipes for matching old work? It will allow me to get an idea without having to buy a lot of different color stains for a small project or two!

Hi,
This is m front door, pine, ca. 1906 stained with a discontinued brand of oil stain, in the Merlot shade, then over-stained with Java Gel stain. It's very dark, shiny and hard to photograph.
It was completely machine sanded pre-stain. The topcoat is garnet shellac applied in the "English Polishing" technique (on a pad like French Polishing without the oil or figure-eight strokes)

Some of the woodwork in the client's house I referenced. The old birch doors, new mahogany mantel were stained with aniline dyes, varying the tint and strength to get the woods to match as well as I could. The topcoats are, again, padded-on garnet shellac. And yeah the pic quality is terrible.

Then my back door, poplar with the merlot/java/garnet shellac/wipe-on gel poly treatment. I added the top coat of poly so it is more grease-impervious and scrubbable.

Pretty doors! Remember to move the birds or the doors first. :)

I realize this post has been quiet for a month but I wanted to ask a few questions.

I have some original doors on our 1940s house that I want to strip. I have attempted one thusfar and it's a huge problem. I am not a stranger to stripping paint but the first coat of paint that was put on this door does not want to come off. I do not know if it is what was referred to as milk paint and this is why the difficulty in removing. Anyway, I may end up having someone dip it for me. My concern is that as far as I can tell there wasn't any sort of finish put on the doors before the paint. I believe the first thing they saw was that original coat of milk paint. I have had to sand the heck out of this door to get this first layer off (did it outside with a mask and a shop vac hooked to sander assuming there is lead in it). I have been able to get out all of the paint residue but since the first layer was a paint will this affect the stainability of the door -meaning it won't look that great if I stain it? I am not sure what wood these doors were made of but I really want to keep the doors as they are nice heavy doors. If staining is a good option how do I go about it - just get a can of minwax and dig in? What do I seal it with after - poly? Thanks.

You need a specific milk paint stripper.

Milk paint companies sell them.

Strong ammonia or lye solutions used to be used.

The modern ones sound like lye since they warn you to keep it away from aluminum.

Lye eats aluminum in a very exothermic reaction.