FLOUR PASTE FOR WATERCOLOURS

Flour paste is a  a useful medium for a watercolour artist. I don't think it is used much-or known about , but it seems reasonably certain that it was used late in life by John Sell Cotman, one of the finest of British watercolourists. Painting with paste means that you have a medium which gives your watercolour a slight  density or body. Your paint will still be more or less transparent like a normal wash.The paint does not run  like a wash and it can be painted into as soon as you like without noticeable spreading. In this example here the orange paint was put down first and the brush cleaned preparatory to making the purple line. There is no significant spreading of the colour.

paste medium-wet into wet-as dried 

Also the paste medium allows you to remove paint or scratch it away almost from the moment you put it down until some considerable time afterwards.The paste dries more slowly than the normal wash.This allows the making of textures with paste which will keep their shape. This wouldn't happen if you dragged an implement through a watercolour wash.

paste medium-scratching into wet watercolour-as dried

You can paint over one layer with another so that further textures may be obtained.If you have too many layers the under layer will likely be disturbed and pick up when you try to apply one layer too many. Remember to use a decent quality watercolour paper for your experiments.

Here is a little watercolour doodle which shows how scratching into paste can  be used in a landscape.

In the foreground you can see where I have scratched into the paste to give a suggestion of texture to a rough moorland scene.In some areas there is wash over the scratchings. I would presume that a traditional watercolourist will use this medium carefully and not make it too obtrusive. There is some scratching out in the distance also-parallel lines upper left.

RECIPE FOR FLOUR PASTE
INGREDIENTS

14gms plain flour (two heaped teaspoonsful) =0.5 ounces (US & UK)

345 mils water (large mug) =11.66 ounces (US )

(THIS MIXTURE GIVES A FAIRLY THICK MIXTURE WHICH CAN BE GOOD FOR SCRIBING AND SCRAPING INTO. IF YOU WANT A FLUID PASTE THEN HALVE THE QUANTITY OF FLOUR.IF IN DOUBT GO FOR A LIQUID MIXTURE WHICH IS VERY RUNNY. IT DOESNT TAKE MUCH IF YOU ARE A TRADITIONAL WATERCOLOUR PAINTER.)



Measure out the water need into a suitable container. Put about 2/3 of the water into a pan and bring to the boil. Mix the flour thoroughly with the remaining water . You can strain this if you wish but I never do. When the water in the pan is boiling add the flour and water mixture  and bring the temperature  of the mixture up to a gentle simmer for 4 minutes.

When the paste is cooked it will appear quit runny but after some time the paste will thicken-this can take up to 30 minutes.You are aiming for something which is less runny than water.The paste will keep best if covered and in a cool place. You will be able to tell if it starts to ferment when it will probably not be usable. You will likely need to experiment a bit but even-or especially quite runny "paste" can be used.
You may wish to keep the paste in a cool place-it will eventually begin to ferment. It is up to you to decide when it is no longer useable. Experiment!

You can make a thicker paste for gluing paper by making a mixture with three  heaped teaspoons of flour to the same volume of water.To this paste you can add approx 20 to 25% of white glue. This will produce an excellent paste for book arts and collage.It is clean and pleasant to work with. The white glue seems to help preserve the flour paste.But it will eventually ferment.In the UK I use something called PVA Bond which is used to glue wood.

My post on Cotman's use of paste is here