Product Design Sketching Tones and Values
While lines are essential to delineate contour and shape, certain visual qualities of surface and volume cannot be fully described by lines alone. Through a combination of lines and tonal values, we create the tactile sensation and appearance we call texture.
Tones and Values Tone is the shading of black to white according to the amount of light falling on various surfaces of objects.
Tones and Values Tonal rendering can imply a shift in the direction of a surface express an overlapping of forms accentuate shape and express the surface contour of an object convey a sense of light and mass add volume to the drawing as a whole suggest texture, value, materials and stimulate visual interest
Ways to Express Tones Tones can be expressed by Pigment (color / darkness) Lines (hatching / crosshatching) Dots (stippling) Scribbles Dashes, etc. hatching crosshatchi ng stippling scribbling
Ways to Create Values Tonal values can be represented by different Grades Spacing Overlapping
Value Scale To create corresponding tones for expressing value relationships of objects in a sketch, start with producing a stepped series and a graduated value scale
Mapping of Values Mapping reduces the many tonal variations that we see into a few. You may begin by sorting the range of tonal values into 3 groups, i.e. light, medium and dark. Within each group, the value may vary to articulate the nature of the surfaces but the overall mapping of the value should remain clear You may squint through half-closed eyes or view a scene through tinted glass which reduces the number of colors and simplifies the values you see