Difference between solvent and medium?

lpbaker · Joined: 18 Aug 2010 Posts: 18 Location: Sydney

I'm been teaching myself oil painting from books and DVDs for a couple of years. I've had some success but I think I'm missing an understanding of some of the absolute basics, including this;

What's the difference between a solvent and a medium? When do you use one, or the other, or a mixture of both?

My primary frustration is how long even simple thin drawing lines take to dry - in some of the videos I watch, the artist paints over construction lines almost immediately with no smudging, whereas I might have to wait hours or even days before that's possible.

Thanks,
Lindsay

Devilbiss · Joined: 06 Jul 2007 Posts: 3214

usually a solvent is used to clean brushes etc and a medium will help you contact dead people.
No no that's wrong. A medium will help your paint either flow better, dry quicker, make glazing possible or even slow the drying of paint. Very Happy

Tango · Joined: 06 Mar 2006 Posts: 1360 Location: Melbourne

Turpentine is a solvent
Linseed oil is a medium
you can thin the medium with a solvent ie, Lindseed oil + turpentine is called a medium even though it contains a solvent
Or you can use a solvent ( turpentine ) like a medium by mixing it directly with the oil paint..
Regarding the seemingly quick drying of the construction lines on the video could be put down to several factors , maybe the drying time was cut from the video or he worked on one that he had prepared earlier or it was a brand of quick drying oil paint, or he under paints using acrylic paint...

art8dave · Joined: 01 May 2006 Posts: 1333 Location: Sydney

The surface of your canvas or board will have an acrylic or oil based gesso.

Some types of acrylic gesso tend to be more absorbent than others, ie the drying time will be quicker on a more absorbent surface, particularly for sketching out your composition.

Acrylic gesso has up to a 50% absorbency, oil based has a 0% absorbency.

A 50/50 mix of Linseed oil and gum turpentine is a good basic medium for oil paints, although there are other commercially prepared mediums which can speed up the drying time dramatically.

lpbaker · Joined: 18 Aug 2010 Posts: 18 Location: Sydney

Thanks for the replies, everyone.