Make a Smooth Transition Between Any Two Images with a Mask Containing a Gradation.
Janet Ashford
CREATING A SPECIAL EFFECT for a book cover, John Odam, of Del Mar, California, used Strata StudioPro to build a simple model of a video camera and two renderings: a wire-frame image and a solid-model image. He combined the two images in Adobe Photoshop by pasting the solid-model image into the colorized wire-frame image through a mask, producing a smooth crossfade from the wire-frame image to the solid image. The camera image was composited with other images for the cover illustration of Communications Media and the Information Society (Wadsworth).
1. Preparing the wire frame. Odam starts by rendering a
wire-frame image of the camera in Strata StudioPro. He opens the
wire-frame image in Adobe Photoshop and inverts it (Image: Map:
Invert), converting it from a black-on-white image to
white-on-black, to suit the rest of the composition.
2. Making it glow. He copies the wire-frame image into a new
channel (Channels Palette: Duplicate Channel), applies a
Gaussian blur (Filter: Blur: Gaussian Blur) with a setting of 12
pixels, and increases the contrast (Image: Adjust) to +60.
Loading the new channel as a mask, he adjusts the levels (Image:
Adjust: Levels) so that the midpoint reads 2.5 and the black
output level is 60.
3. Converting to color. After converting the image from
grayscale to RGB (Mode: RGB), Odam selects the red channel
(Command-2), uses the Select All command (Select: All), and
fills it (Edit: Fill) with black. The resulting image contains
only green and blue, making a bright-cyan wire frame.
4. Outlining the mask. Now Odam uses the solid rendering of the
video camera from StudioPro as a template for creating a
graduated mask. He selects the white area with the magic-wand
tool and inverts the selection (Select: Inverse). He then pastes
the selection into a new channel (Channels Palette: New Channel)
and fills it with white. Duplicating the channel (Channels
Palette: Duplicate Channel) preserves the camera selection.
5. Creating the crossfade mask. With the camera outline
selected, he drags the blend tool across it to create a
gradation from black to white. Returning to the wire-frame
image, he loads the mask (Load Selection) into the image from
channel #5 of the solid-model image.
6. Crossfading the images. Returning to the solid-model image,
Odam selects the camera (Load Selection: Channel #4) and copies
and pastes it into the wire-frame image (Edit: Paste Into). The
resulting image is a crossfade of the solid-model and the
wire-frame images.
Janet Ashford is the coauthor, with Linnea Dayton, of Adobe Illustrator: A Visual Guide for the Mac (Graphic-sha/Addison Wesley, 1995).
