painting the figure
module 1: supplies
B: Oil Paints
One the main draws to using oil paint. Mediums help manipulate the feel of the paint that you're using and they open up different special effects to you.
Every manufacturer of paint has their own brand of linseed oil. I don't really have a preference one way or the other when it comes to linseed oil manufacturers. It is the binder for pigment and oil paint (the "oil" in "oil paint.") The more oil you add to your paint the less pigment there is, so you want to use it pretty sparingly. With any medium you don't want to add too much to the paint itself. It begins to become less paint and more binder. There's less pigment to the mixture so there's less vibrancy in your color. Also, it becomes a bit more unwieldly. You can pretty much use any professional grade linseed oil for the same effect. It's really just there if you use a stiff paint or your pain is starting to become stiff on you. Use a little bit of it to loosen it back up and make it flow on your canvas a little bit easier. A lot of people only use linseed oil as a medium if they even choose to use medium.
M. Graham's walnut alkyd medium
You may have heard of Galkyd or Liquin. Those are also alkyd mediums. Alkyd is I believe a resin or a polymer that is added to paint to make it dry quicker. I believe there's something in the in the alkyd that speeds up the oxidation process, which is what oil paint uses to dry permanently. I prefer the Walnut alkyd medium just because it doesn't gum up as easily as Galkyd or especially Liquin. It's a good medium for making paint dry quicker especially when working under deadlines. It's one of my preferred additions to my oil paint in order to make it dry quicker.
Pale drying oil by Natural Pigments
A linseed oil heat treated with dryers (without lead) that dries faster than refined or boiled linseed oil. It provides gloss, improves handling and drying of oil colors. Add directly to colors or mediums to speed drying, and increase hardness.
"One of the things that happens with some of the oil paints as they dry(especially the earth colors)they become more matte. That's just because of the way the pigments absorb the linseed oil. The less oil there is, the more matte of a surface you will end up with. Any of these mediums will increase gloss, so if you want that glossy look to your paint, you add some medium to it. The reason I like the pale drying oil over even the alkyd medium is because it provides some of the the quicker drying properties that alkyd has. they don't speed the process as much as alkyd but has a feel that's more like linseed oil. It's a subtle difference, but different enough. This has been my preferred medium for a few years now.
Gamblin solvent-free gel
It's a clear gel that has alkyd in it so it dries relatively fast. Not quite as fast a thin layer of medium but the nice thing about it is that a gives some extra body to your paint. You can give the appearance of a thicker paint without having to use a lot more paint. Because it has alkyd in it, it also means that you can use thick paint that will dry relatively quickly, as opposed to you not using any sort of quick dryer or thick paint at all. You're looking at weeks worth of drying time if you paint that way.
There are so many different mediums out there. You can have a lot of fun experimenting with them and there's a ton of research you can do on those. I'll leave it up to everybody who wants to dive deep into it to do their own research.