Adobe Photoshop CS2 On Demand [Electronic resources]

Working with Linear and Non-Linear History

The History palette records each step performed on a Photoshop document in a linear fashion from top to bottom. However, the purpose of the History palette is not to simply record your progress through a document, it's there to help you make changes and go back in time to correct mistakes. Photoshop handles the History palette in two ways-linear and non-linear. When you work in a linear History palette, clicking on a previous step causes all steps underneath to gray out. If you then add a step, the grayed out steps are removed and the new step is added to the bottom of the list. A linear palette is organized and is very RAM efficient, however, once a History Step is removed, it cannot be retrieved. When you work in a non-linear History palette, clicking on a previous step does not cause the steps underneath to gray out. If you then add a step, the new step is added to the bottom of the History palette. The new step represents the characteristics of the step you selected, plus any added actions. A non-linear palette is not organized and consumes more RAM memory. It's advantage lies in the fact that History steps are not deleted; they are simply reorganized.

Work with Linear History

Select the

History palette.

Click the

History Options button, and then click

History Options .

Clear the

Allow Non-Linear History check box, and then click

OK .

Work in the document until you have generated ten or fifteen steps in the History palette.

Move halfway up the History palette, and then click on a step.

The steps below the selected step turn gray.

Perform another action to the image.

The grayed steps are removed, replaced by the latest action applied to the image.

Work with Non-Linear History

Select the

History palette.

Click the

History Options button, and then click

History Options .

Select the

Allow Non-Linear History check box, and then click

OK .

Work in the document until you have generated ten or fifteen steps in the History palette.

Move halfway up the History palette, and then click on a step.

The steps below the selected step do not change.

Perform another action to the image.

The new step is added to the bottom of the History steps.