Water in watercolor painting technique is of equal importance to the pigment. Water is not just medium to make the pigment flow during application but an integral part of the pigment itself when applied and on drying leaves a permanent record of its former presence.
Water should be fresh wholesome and taken from a known reliable source. It should smell fresh and sweet in the same way as potable water does to the palate. Use water with a neutral pH acid alkali ratio or distilled.
Falling temperatures humidity chemical content each affect how the water behaves during its use. This affects the drying times of the painting. The appearance of washes too is affected by dry times as the position of pigment particles moves more during longer dry times. This is because the supporting board is given a tilt to prevent puddling of the water at inappropriate places on the ground [paper]. Greater movement of the pigment particles lifts the pigment from one area of the ground and precipitates it to another. This alters the original tonal balance of the pigment. When the wash was laid the color effect was one thing but when dry it becomes altered. To bring your wash to the result you wish in this instance you need to understand the water as much as the pigment in the application technique.
The condition of the air and its effect on water dry times for more or less standard washes can be even more pronounced when wet in wet washes are used. If the ground [paper] has water within its thickness ready to receive a wet wash dry times can be doubled. The amount of water to be absorbed will vary according to its thickness. This thickness affects dry times of wet in wet washes more than it does in thinner grounds. Final results are more difficult to judge.
This article is not about washes but about water. The technique of laying down washes or water containing pigment is another ball game to be treated in these articles elsewhere.
Water will cause thin grounds to buckle. Buckling in effect is irregular stretching. The more water used the greater liability there is to buckling which is also a variation of dry times within the ground. The greater the water content of the wash the thicker the ground needs to be. Thick dry papers absorb water quicker from watercolor to dry with firmer stronger tonal values.
Uneven dry times in a wash will make the wash appear patchy or uneven and spoil the finished work. Uneven dry times will also make it impossible to lay down further washes and the original unevenness will show through later washes.
Too much water will make a wash look weak when it dries even if drying is even. Loss of pigment strength will result in loss of color and tonal balance.
Water dry times will be affected by time of day rising or falling temperatures variations in humidity and the seasons of the year. Also altitude above sea level will affect air density related to temperatures. Water hardness or softness will affect longevity of the painting hence the need for neutral Ph value of water as well as in the ground. Textured papers loved by watercolorists need more water.
Dry times of water affect speed of work. Waiting for washes to dry takes away spontaneity from the work. If working to beat the clock dry times are important and washes will need to be drier than at other times. Here the subject of the painting does not decide technique. Outdoor quick dry painting favors less water.
Water left overnight should not be used next day because of bacteria and possible fungus growth. Sniff to smell if the water to detect if it is even slightly off or tainted. If you are doubtful about the water it must be discarded. Old pigmented watercolor has a vile smell. Get rid of this and clean where it may have spilled.
There are many other aspects of interest about water but these are better dealt with when discussing technique and specific painting objectives.
