Friday, June 29, 2007
Mastering this tool will help to ensure that you have continuous tones in your images
Smooth transitions. They're the essence of continuous-tone images. In most cases, you want to preserve them. On occasion, you want to modify them. Sometimes, you want to create them.
While gradients can be extremely complex and yield highly sophisticated results, once the basic principle behind them is firmly grasped, they're simple to create and use. Using the Gradient tool, a gradient is created between the start (where you click first) and end points (where you drag to). The start and end points may be placed anywhere on the canvas. Gradients can be drawn for any length at any angle.
The shorter the distance between the two points, the tighter the gradient will be, with more abrupt tonal transitions. The longer the distance between the points, the softer the gradient will be, with smoother tonal transitions. Favor longer gradients with smoother transitions. They can always be tightened and repositioned by adjusting contrast. Reducing contrast won't produce the opposite effect; it will posterize the gradient.
There may be times when you want to place a start or end point outside the border of an image. You can do this by expanding the window around the image. Click and drag on the lower right-hand corner of the window. Gray will be seen surrounding the image, but inside the window. A start point, end point, or both, may be placed anywhere within the window.
There are five types of gradients from which to choose: Angle and Diamond are of limited use; Linear, Radial and Reflected are very useful. Linear uses the start and end points to define a gradient along a line. Radial uses the start and end points to define the radius of a circle. Reflected uses the start and end points to define the center (foreground color) and outsides (background color).
There are 15 “colors” from which to choose, but the first two serve most purposes: Foreground to Background, and Foreground to Transparent. Classically, black-and-white or shades of gray are most frequently used.
Gradients can be extraordinarily flexible. You can alter the characteristics of a gradient by checking the Edit button under the gradient Options palette. If you don't get precisely the effect you're looking for, you can try again. Or, if you're dealing with a monochromatic gradient, there's an easier way. After creating a gradient slightly longer than you think you need, apply a Curves adjustment to the gradient (Image > Adjustments > Curves).
1. Move the midtones up or down to shift the midpoint of the gradient.
2. Move the highlights up and the shadows down to quicken the transition between end points.
3. Move the white point down to turn white to gray.
4. Move the black point up to turn black to gray.
5. Move the white point to the black point and the black point to the white point to invert the gradient.