WAX

I will never varnish again- never. I almost ruined the last painting I vanished- even though I uses a conservator recommended vanish and appropriate expensive natural bristle brushes (foam brushes are worse). It was a very large painting and though I keyed it drum tight, there were still slight depressions where the varnish pooled. Unfortunately I had not thinned my varnish as much as I usually do- not something that was recommended on the label, and it is a glossy, glittery mess.

After this I decided to investigate wax mediums. I had heard about it and seen some paintings done this way. Wax has a long history, the encaustic Fayum portraits http://commons.wikimedia.org/wiki/Fayum_mummy_portraits are over 2000 years old and some look as fresh as the day they were created.

I talked to some conservators about using a wax medium and I was told it was valid and safe. The conservator from a well-known museum who I talked to at length told me not to reveal his name or institution- but anyone can call major museums and talk to conservators. Conservation and archival services that service museums can point you in the right direction as well.

I add 10 to 15 percent wax medium to my oils. You can use Dorlands http://www.google.com/products/catalog?q=dorland's+wax+medium&hl=en&prmd=imvns&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1280&bih=905&um=1&ie=UTF-8&tbm=shop&cid=2595341877453089966&sa=X&ei=3YBjT-S-GsGhtweKuumGCA&ved=0CFwQ8wIwAQ

Or better, Gamblin's: http://www.dickblick.com/products/gamblin-cold-wax-medium/
The Gamblin site will  give you some great information on its use.

The benefits are manifold. You get no sinking in of color like you do in plain oils, instead you get a lovely even sheen.You don't have to oil it out or use a retouch varnish. It is great in flat areas that you want to keep as flat as possible- I have used the flat of my hand or a straight-edge. You can make a nifty glaze with it. I visited a portrait that I painted over 5 years ago recently and it showed no signs of dulling paint. That is so much better that having to varnish a painting in situ. Furthermore, there is no varnish to remove- the conservator told me, that no matter how careful and skilled a conservator is some small amounts of color do come off during cleaning when a varnish is removed. I make a note on the back of my painting that it is done with a wax medium- so they are not to varnish it.

I use Micheal Harding's cremnitz white with walnut oil, not a fast drier, so my drying times are relatively slow. I have not noticed the wax making it any slower.

You will have to experiment with this yourselves, make inquiries- but so far I find this a very satisfying medium.