Glazing was an important part of traditional skills, managed most notably by Titian. Though absent from direct painting, and therefore neglected by many contemporary painters, glazes allow pictures to be built up carefully, and final color or tonal imbalances to be corrected. Below are recipes for typical glazes and retouching varnishes.
The ingredients are not expensive, and you should try their effect with different pigments, noting:
1. Handling properties
2. Drying times
3. Resulting finish.
There is considerable dispute among authorities as to what glazes work best, and which are the safest. Experiment.
Medium No. 3 (Damar varnish and linseed oil.)
Medium No. 4 (Damar varnish, sun-thickened linseed oil and Venice turpentine.)
Medium No. 5 (Stand oil/sun-thickened oil, Damar varnish and turps.)
Medium No. 11 (Venice turpentine and linseed oil.)
Medium No. 13 (Heavy, sun-thickened linseed oil, Venice turps and turps.)
Medium No. 16 (Oil-copal varnish No. 7, heavy stand oil and turpentine.)
Medium No. 17 (Oil-copal varnish No. 7 and linseed/poppy oil.)
Medium No. 20 (Beeswax, Damar varnish, sun-thickened linseed oil & turps.)
Note that varnishes shouldn't be applied earlier than six months after completion of painting. Also that varnishes with copal are not easily removed.
Varnishes Varnish No. 1 (Damar lumps and turpentine. Called Damar varnish above.)
Varnish No. 7 ( Copal lumps and linseed oil.)
Varnish No. 3 (Copal lumps, petrol and turpentine.)
Varnish No. 10 (Damar varnish No.1 and wax varnish No. 20.)
Varnish No. 11 (Damar varnish No. 1, beeswax and turpentine.)
Varnish No. 14 (Damar varnish No. 1, sun-thickened linseed oil & Venice turps.)
Varnish No. 17 (Venice turpentine and sun-thickened linseed oil.)
Varnish No. 21 ( Beeswax and turpentine.)
Check out the websites listed for oil painting materials and techniques, but note that glazing is better covered by older works, of which these may be the more useful:
1. Cad-Red. Useful information on oils, pigments and how to prepare paints and canvases.
2. Kama Paints. Online demonstrations on how to make oil paints.
3. 'The Artists's Handbook of Materials and Techniques' by Ralph Mayer. 5th Edition. Viking Press. 1991.
4. 'What Every Artist Needs to Know About' by David Pyle. Krause Publications. 2000.
5. 'The Materials of the Artist and their Use in Painting' by Max Doerner. Harvest Books. 1984
6. 'Formulas for Painters' by Robert Massey. Watson-Gupthill. 1980.
7. 'The Artist's Methods and Materials'. M. Bazzi. John Murray. 1960.
8. 'The History, Definitions, and Techniques of Oil Painting'. Sander's Studios. One of many detailed pages on this site.
9. 'Oil Painting'. Visual Arts Cork. Supplements this site: with recommended paintings.
'Bacchus and Ariadne' by Sebastiano Ricci. c.1716. Germanisches Nationalmuseum. Nuremberg. A warm and well-finished painting in reds mostly but including muted areas of blue and blue-green. The detail shows the rich effects possible with glazes.