Cast shadows and lamp height
A cast shadow is a second drawing of the object, projected onto the table, and it is distorted by the angle of the lamp. A low lamp throws long shadows that lie far from the objects; a high lamp throws short, compact ones tucked underneath.
Shadows also connect objects: where two shadows overlap, or where a shadow touches the next object, the eye understands the space between them.
The three heights in the pictures: the lower the lamp, the longer the shadow, by simple trigonometry.
What to look for
The shadow is longest and thinnest when the lamp is lowest.
Directly overhead the shadow almost disappears beneath the fruit and the table looks bright and flat.
Where a shadow falls on another object it wraps around that object's form.
The shadow always points away from the lamp: you can find the lamp from the shadows alone.
Lower the lamp and the shadows grow long and touch the next fruit; raise it and they shrink under each one. Read the length as a multiple of the height.
The set-ups, with numbers
Each card is one lamp position: the picture it makes, a diagram of where the lamp stands (azimuth is measured from the camera: 0° is a lamp at the camera, positive turns it toward the picture’s left, 180° is straight behind; elevation is the angle above the table), and the values measured on the form itself.
In painting and in photography
A cast shadow is a second drawing of the object. Painters use it to anchor an object to its surface and to link objects to each other.
Shadow direction is how a viewer reads the position of the lamp, and the time of day. Hard cast shadows on a table make a product look grounded.
Now youAcademy & Pro
Drag the lamp's elevation from 10 to 80 degrees and watch the three shadows shorten together. Switch to the Shadow view to see only the shadows.
Open this lesson in the Light Study Room
The room opens with the shape and the first set-up already loaded, and the same diagram you see here follows your lamp as you move it. Drag the lamp’s marker on the picture, or move it on the pad, and switch between Picture, Light only, Surface and Shadow. Or open it from inside the studio: the Study button in the bottom bar, then Academy lessons. The Light Study Room is a separate classroom for learning light on 3D shapes; when you are ready, “Send to studio” takes the shape into the main editor.
Exercises
- From the shadows alone, work out where the lamp is. Then check on the pad.
- Raise the lamp until the three shadows are the same length as the objects are wide.
- Make two shadows overlap. Where is the overlap darkest?