What is meant by form and cast shadows?
There are two kinds of shadows that occur when one light shines on an object, a cast shadow and a form shadow...
- Cast shadow: When an object blocks a light source it creates a shadow. A cast shadow is not a solid shape but varies in tone. The further a cast shadow is from the object the lighter and softer and less defined its edges become.
- Form shadow: A form shadow is the less defined dark side on an object not facing the light source. Form shadows are subtle shadows, but they are essential for creating the illusion of volume, mass and depth.
As with everything the key (no pun intended) to painting shadows successfully is careful observation. Assess the tone, colour, shape and quality of edge just as you would the object itself.
Tones are the different values between white and black. Artists use tone to translate the light and shadows to create the illusion of form. Tone is the magical illusion of three-dimensional reality that appears on your paper. Look for the lightest areas on the object. The very brightest of the lightest tones are called highlights. Dark tones often reveal the sections of the object that are in shadow. By locating shadows, you can usually identify the light source. A full range of tones adds depth to your painting.
The shadow that is cast by the object is usually lighter in tone than the form shadow, but it is always darker than the highlight. Depending on the colour of the object, the surface receiving the cast shadow, and the surface textures there may also be reflected light cast upon the object or reflected into the shadow from the object. This is where careful observation pays dividends.
A transparent watercolour wash can be glazed directly over an area of a picture, either by way of a flat wash or a graded wash depending on the surface of the object, to create a shadow and the detail will still show through.
Alternatively paint the shadows first, adding colour and detail over the top when the first wash is dry. This is the magic of watercolour - it acts like light.
What differences are there between natural and artificial light?
What happens when there is no light?
What happens when an object stands in front of the light?
Will the shade be the same if we change the position of the light?
In Painting shadows - part 2, I will deal with the colour of shadows, shadows in perspective and quality of their edges.