Adobe illustrator 10 Manuale Utente

Adobe Illustrator calculates the number of steps in a gradient based on the percentage of 
change between the colors in the gradient. The number of steps, in turn, determines the 
maximum length of the blend before banding occurs. 

The gradient’s number of steps and maximum length assume that you are printing the file 
with a line screen and resolution that produce 256 levels of gray.

1 Select the measure tool  , and click the beginning point and the endpoint of the 
gradient.

2 Note the distance displayed in the Info palette on a piece of paper. This distance repre-
sents the length of the gradient or color blend.

3 Calculate the number of steps in the blend using this formula:

To figure out the percentage change in color, subtract the lower color value from the 
higher color value. For example, a blend between 20% black and 100% black is an 80%—
or 0.8—change in color. 

When blending process colors, use the largest change between the colors. For instance, 
a blend from 20% cyan, 30% magenta, 80% yellow, and 60% black to 20% cyan, 90% 
magenta, 70% yellow, and 40% black indicates a 60% change, because the greatest 
change occurs in magenta, from 30% to 90%.

4 Using the number of steps calculated in step 3, see if the length of the gradient is larger 
than that indicated in the chart. If it is, reduce the length of the gradient or change the 
colors.

10

21.6

.3

.762

20

43.2

.6

1.524

30

64.8

.9

2.286

40

86.4

1.2

3.048

50

108.0

1.5

3.810

60

129.6

1.8

4.572

70

151.2

2.1

5.334

80

172.8

2.4

6.096

90

194.4

2.7

6.858

100

216.0

3.0

7.620

110

237.6

3.3

8.382