In the painting titled "Cedar," one of the more difficult effects that I tried to create was the shadow of a tree sweeping across the wall (Figure 4.30). The shadow is long because the light source is the setting sun, which is low on the horizon.
Figure 4.30. In the "Cedar" image, one of the more difficult effects that I tried to create was the shadow of the tree sweeping across the wall.
The tree itself is used to create the shadow. The tree trunk and the leaves are created in multiple layers that are merged together into a single layer once the tree is completed. This procedure is outlined in further detail in Chapter 3, "A Greener World: Creating Foliage," on creating foliage.
The layer that contains the merged tree is duplicated by dragging it over the Make New Layer icon at the bottom of the Layer's palette (Figure 4.31).
Figure 4.31. The layer that contains the merged tree is duplicated.
With Preserve Transparency turned on for the layer, fill it with black. Because the tree exists on a transparent layer, with Preserve Transparency turned on, when you select Edit>Fill, only the tree is filled. This black fill serves as the basis of the shadow (Figure 4.32).
Figure 4.32. With Preserve Transparency turned on for the layer, it is filled with black.
Preserve Transparency allows you to modify only the pixels in the layer that are active. The transparent area of the layer retains its transparency.
Preserve Transparency is turned off to apply a Blur filter to soften the shadow.
The Blur filters create their effect inward and outward from the edge of the object being blurred. A Gaussian Blur of 10 softens the edge by 5 pixels inward and by 5 pixels outward. If Preserve Transparency is turned on, the outward effect is disabled. This looks very unnatural.
Use the Scale tool (Edit>Transform>Scale) to stretch the black tree to the width of the entire image (Figure 4.33). This achieves an effect of a long shadow across the wall.
Figure 4.33. Using the Scale tool, the black tree is stretched to the width of the entire canvas.
The shadow is supposed to darken the underlying layers. To achieve this effect, the mode for the layer is changed to Multiply. This mode actually multiplies the brightness values of the pixels with the pixels under it. This considerably darkens the layers underneath the shadow. Finally, the Opacity was lowered so that the shadow would soften.
Because the shadow is long and casts against a wall at an angle, the shadow must blur out more at the outer edges than the area immediately behind the tree. It also appears to stretch as it gets further away from the source. To help achieve this effect, an alpha channel is created with a horizontal gradient from white to black (Figure 4.34).
Figure 4.34. An alpha channel is created with a horizontal gradient from white to black.
The alpha channel is then loaded as a selection. In this way, the left side of the image is fully selected, but the selection becomes weaker as it moves closer to the right side. A Motion Blur filter is applied to the layer of the shadow, as shown in Figure 4.35. Thanks to the selection, the more distance from the tree, the stronger the effect. The result is the desired effecta stretched and blurred shadow that is cast by the tree across the wall. Deselect the gradient before proceeding.
Figure 4.35. The effect of the Motion Blur filter softens and stretches the shadow as it gets further away from the tree.
As a shadow moves away from its source, it gets lighter. To achieve this effect here, a layer mask with a gradient is applied.
In a layer mask, black hides the contents of the layer; white makes them visible. I did not want the shadow to completely disappear, so I created a gray to white gradient in the layer mask rather than a black to white gradient, as shown in Figure 4.36. This gradually lightens the shadow as it moves to the left.
Figure 4.36. A gradient is created in the layer mask that went from gray to white.
The painting "handles" also has long shadows that bend to the contours of the objects they are cast onto (Figure 4.37). The same procedure that used two shadows to simulate one is used here.
Figure 4.37. The painting "handles" has shadows that travel down the face of the cabinet and then bend onto the floor.