PLEIN AIR - Technical


Needing more bespoke sizes to cope with a 'wide landscape format' I sometimes prefer plywood (though it is  more preparation, work) to the rather sterile surface of MDF - when you get up close you see the subtle effect of woodgrain under the brushstrokes. (MDF is very convenient for small ready cut pieces though)
Method: I bought two sheets of 8ft x 4ft x 3mm ply from Meyer Timber, (specialist ply importers), bumpers farm, Chippenham). This  wood is great as it lies absolutely flat though it is so thin.  Cut to size with  a very sharp stanley knife, measuring very accurately and scoring both sides, the wood easily cuts. Primed with slightly diluted emulsion to seal the wood, then with gesso acrylic primer, I sand down the 'tooth' slightly as this mercilessly wears my brushes away. Then tone down with a warm translucent base colour (the colour can vary) and ready to go.
Popular sizes are 10" x 20", 10" x 32", 12" x 32", 20" x   34" 8" x 24"
These long strips can very easily be cut to more standard 6" x 8", 10" x 12 etc

Making sun-thickened linseed oil

Spring is here, time to make a new  batch of sun thickened oil - a very useful medium for plein air painting.
Using a purified cold pressed, linseed oil, pour the oil into a shallow plate (about 5mm deep),  then this needs to be covered with a sheet of glass to keep dust out . he process works by oxidation  so the glass needs to be raised somehow to allow air in. Put on  a sunny windowsill, the more sun it gets the better. Air on the surface of the oil  and ultraviolet rays from the sun start a slow drying and thickening process. It is important to remember to stir the oil every day to prevent  a skin forming. After say three weeks  the oil will be thicker and more viscous. Decant into  an appropriate air tight storage bottle This is  a great medium for plein air painting as it is half oxidized so dries quickly allowing  the painting to be worked on in thicker layers without it getting too oily and slippery. The oil yellows slightly in the process and dries with some shine. As with all new medium, it  needs  a little  practice to understand its  properties, and the viscous flow should  be adjusted by adding turpentine,  (or Zest-it!) to suit your painting process. ( a recipe from  "The Materials of the Artist" by Max Doerner.  - quote: Cennini calls it the best of all oils "I could not give you anything better")
  •   With sable and other soft hair brushes -  sometimes a gentle wash  in soap and warm water, followed by  a touch of hair conditioner can restore some suppleness and life back into the brush. Being lazy but resourceful, I use hair a combined shampoo/conditioner.
  • If small pointed sables lose their shape - using liquid gum arabic to persuade the hairs back into shape, left to dry to a point and this can give bit more shape and so longer life to those brushes.