Photoshop cs5 by steve Johnson part 21 pptx

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Working with the History
Panel
Introduction
Adobe introduced the History panel in Photoshop 5, and the
graphic design world hasn't been the same since. On an ele-
mentary level, the History panel gives you the ability to per-
form multiple undos. Think of History as a magical mistake
correction tool that never wears out. However, the History
panel does much more than give you the ability to go back in
time and correct your mistakes. The History panel is simply a
tool, but when you combine the power of the History panel
with the History brush and the Art History brush, you have a
trio of tools that can take your creative designs to the next
level and beyond.
Adobe Photoshop gives you two ways to use the History
panel—linear and non-linear. The
linear
mode helps you keep
track of your recent steps, and erases any steps that interfere
with a linear flow to the panel. The
non-linear
mode pre-
serves all the steps (linear or non-linear), and is useful when
you need to think outside the linear box.
Photoshop raises the bar with the History panel by giving
you the ability to record and save the commands performed
to a document in a text file. Now, you can finally know
exactly what you did to an image. And since the document
can be printed, you can create History text documents of
your favorite restoration and manipulation techniques, and

save them.
In addition, when you combine the History brush with the
History panel, you have an awesome creative tool that can't
be beat. In fact, it's even possible to convert the Eraser tool
into a History brush.
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What You’ll Do
Set History Panel Options
Work with Linear and
Non-Linear History
Control the Creative Process
with Snapshots
Duplicate a History State in
Another Document
Save the History State of a Document
Review the History State Text File
Combine the History Brush with a
History State
Use the Art History Brush
Change the Eraser Tool into the
History Brush
Control History States
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128 Chapter 6
Working with the History panel requires a firm understanding of how
the panel functions, and what you can and cannot do with History. The
History panel records your steps as you work through a document. A

step is defined as a specific action, such as creating a layer or adding
a brush stroke. Every time you perform an action, a step is recorded in
the History panel. The History panel gives you the ability to go back to a
previous history state, which is the same as performing an undo com-
mand. You can perform multiple undo commands up to the number you
set in Photoshop preferences for the History States. In addition, the
History panel creates snapshots of the document. Snapshots are
images of the current state of the document. Snapshots are used in
conjunction with the History and Art History Brushes to create special
effects.
Setting History
Panel Options
Set Number of History States
Click the Edit (Win), or Photoshop
(Mac) menu, point to Preferences,
and then click Performance.
Enter a value from 0 to 1000 for the
number of steps recorded in the
History States box.
Click OK.
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Did You Know?
You can duplicate a History State.
Hold down the Alt (Win) or Option
(Mac) key, and then click the History
State you want to duplicate.
You can use keyboard shortcuts to

perform multiple undos.
The History
panel represents the ability to perform
multiple undo commands. However,
when you press Ctrl+Z (Win), or A+ Z
(Mac) you only move back and forth
between the last two commands, just
like a normal undo. To perform multiple
undo commands, press Ctrl+Shift+Z
(Win) or A+Shift+Z (Mac) to move
forward through all your History steps,
or press Alt+Shift+Z (Win) or
Option+Shift+Z (Mac) to move back-
wards through the available History
steps.
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Chapter 6 Working with the History Panel 129
Set History Options
Select the History panel.
Click the History Options button,
and then click History Options.
Select the check boxes for the
History Options you want to use:
◆ Automatically Create First
Snapshot. Creates a snapshot
(image) when the document
first opens.
◆ Automatically Create New
Snapshot When Saving.

Creates a snapshot every time
you save the document.
This is useful for keeping track
of the changes made to a
document.
◆ Allow Non-Linear History.
Allows you to operate History in
a non-linear state.
◆ Show New Snapshot Dialog By
Default. Opens a dialog box
with options each time you
create a new snapshot.
◆ Make Layer Visibility Changes
Undoable. Instructs Photoshop
to make any changes made to a
layer's visibility undoable.
Click OK.
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130 Chapter 6
The History panel records each step performed on a Photoshop docu-
ment in a linear fashion from top to bottom. However, the purpose of

the History panel is not to simply record your progress through a docu-
ment; it's there to help you make changes and go back in time to cor-
rect mistakes. Photoshop gives you two History panel modes—linear
and non-linear. When you work in a linear History panel, clicking on a
previous step causes all steps underneath to become grayed out
(unavailable). 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 panel is
organized and very RAM efficient; however, once a History Step is
removed, it cannot be retrieved. When you work in a non-linear History
panel, clicking on a previous step does not cause the steps underneath
to become grayed out. If you then add a step, the new step is added to
the bottom of the History panel. The new step represents the charac-
teristics of the step you selected, plus any added actions. A non-linear
panel is not organized and consumes more RAM. Its advantage lies in
the fact that History steps are not deleted, they are simply reorganized.
Working with Linear
and Non-Linear
History
Work with Linear History
Select the History panel.
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 10 or 15 steps in
the History panel.
Move halfway up the History
panel, 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.
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Chapter 6 Working with the History Panel 131
Work with Non-Linear History
Select the History panel.
Click the History Options button,
and then click History Options.
Select the Allow Non-Linear
History check box.
Click OK.
Work in the document until you
have generated 10 or 15 steps in
the History panel.

Move halfway up the History
panel, 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.
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Did You Know?
You can quickly purge the History
States, and therefore recoup addi-
tional RAM.
Hold down the Alt (Win) or
Option (Mac) key, click the History
Options button, and then click Clear
History. But be warned; there is no
undo available. You are stuck with your
decision.

You can reduce memory usage by
using linear history.
Non-linear History
requires more RAM to maintain. If you
don’t require a non-linear history and
want to decrease RAM usage, then
you can turn it off. In the History panel,
click the History Options button, click
History Options, clear the Allow Non-
Linear History check box, and then
click OK.
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132 Chapter 6
The History panel contains more than just steps; it also holds
Snapshots. A Snapshot is an image of the document as it exists at the
time the snapshot was taken. The History panel can hold as many
snapshots as needed, and they are not subject to the number of History
States you chose in Preferences. That means they stay with the docu-
ment throughout the creative process. By default, Photoshop takes a
snapshot of the image when it first opens. This snapshot represents the
original state of the image, before any adjustments or modifications are
applied, and is identified with the file name of the image. It's a good
idea to create a snapshot every time you make a major change to the
image. That way, if you want to start all over, all you have to do is click
on the snapshot, and Photoshop returns you to the moment in time in
which the snapshot was created. It's like having your own personal
time machine.

Controlling the
Creative Process
with Snapshots
Create Snapshots
Select the History panel.
Click the History Options button,
and then click History Options.
Select the Show New Snapshot
Dialog by Default check box, and
then click OK.
Perform several actions to the
image.
Click the Create New Snapshot
button.
Type a name for the new snapshot.
Click the From list arrow, and then
click a save image information
option:
◆ Full Document. Saves the
entire visible image and all
layers.
◆ Merged Layers. Saves only the
merged layers.
◆ Current Layer. Saves only the
active layer.
Click OK.
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Chapter 6 Working with the History Panel 133
Here's a tool to help you gain control over the creative process, and
save you a lot of time and effort as well. The History panel lets you
create new documents based on a specific History step or snapshot.
For example, you're working on a complicated image, and you want to
isolate a portion of the image in another document. This will not only
help you reduce the clutter, but working on a portion of the image in a
separate document creates a document with a much smaller file size,
and that will help Photoshop work faster.
Duplicating a History
State in Another
Document
Create Another Document
Select the History panel.
Click on the snapshot or History
State you want to use for the new
document.
Click the Create New Document

From Current State button.
Photoshop creates a new
document based on the selected
snapshot or state. The new
document's History panel contains
one snapshot or one state.
IMPORTANT
Snapshots are
not saved with the Photoshop
document. When you reopen a
document, the History panel will
display one snapshot of the
current state of the image or one
History state.
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New document based on the
selected snapshot or state.
Did You Know?
You can save RAM by using the
History panel.
When you create a new
document using the History panel, it’s
very RAM efficient, as opposed to the
traditional copy and paste method.
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