In this chapter, you will choose default set-tings for the History panel; restore, delete, and clear history states; preserve states by using snapshots; create a new document from a stat
Trang 1IN THIS CHAPTER Choosing History panel options 175 Changing history states 177 Deleting and clearing history states 178 Using snapshots 179 Creating documents from states 181 Using the History Brush tool 182 Filling an area with a history state
or snapshot 184
10
tively undo or restore previous stages
(called “states”) of the current work
session In this chapter, you will choose default
set-tings for the History panel; restore, delete, and clear
history states; preserve states by using snapshots;
create a new document from a state or snapshot; and
restore areas of an image to a prior state by using the
History Brush tool or by filling a selection or layer with
a history state
Choosing History panel options
The History panel displays a list of states (edits)
that you have made to the currently open document
The most recent state is listed at the bottom When
you click a prior state, the document is restored to that
stage of the editing process What happens to the panel
when you do this depends on whether it’s in linear or
nonlinear mode,Aso you need to learn how the two
modes differ
Continued on the following page
Current
history state
and history
state slider
Create New Document
from Current State
Create New Snapshot
Delete Current State
A This History panel is in linear mode When we clicked
an earlier state, the subsequent states became dimmed.
Source for
the History
Brush tool
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Choosing a mode for the History panel
To choose a mode for the panel, choose History
Options from the panel menu, then in the History
Options dialog, check or uncheck Allow
Non-Linear History We recommend keeping the
History panel in linear mode (unchecking the
Allow Non-Linear History option), especially if
you’re new to Photoshop.AWith the panel in
this mode, if you click an earlier state and resume
image editing from that state or delete it, all the
subsequent (dimmed) states are discarded This
way, the document can be restored to an earlier
state with a nice, clean break
In nonlinear mode, if you click on or delete an
earlier state, subsequent states aren’t deleted or
dimmed If you resume image editing when an
earlier state is selected, your next edit will show up
as the latest state on the panel, and all the states in
between will be preserved That is, the latest state
will incorporate the earlier stage of the image plus
your newest edit If you change your mind, you can
click any in-between state whenever you like and
resume editing from there.BNonlinear is the more
flexible of the two modes, but it can be confusing
or disorienting
B This History panel is in nonlinear mode When
we clicked an earlier state, all the states remained available, even those listed below the one we clicked.
A In the History Options dialog, uncheck Allow Non-Linear
History for linear mode, or check it for nonlinear mode.
Choosing other options for the History panel
The last option in the History Options dialog,
Make Layer Visibility Changes Undoable, controls
whether clicking the visibility icon on the Layers panel is listed as a state on the History panel We prefer to keep this option off (For other options in this dialog, see page 179.)
To specify the number of states that can be listed on the panel at a time, go to Edit/Photoshop >
Preferences (Ctrl-K/Cmd-K) > Performance and,
under History & Cache, enter a History States
value (the default value is 20) If the maximum number of history states is exceeded during an editing session, the oldest steps are removed to make room for new ones The maximum number
of states may be limited by various factors, includ-ing the image size, the kind of edits made to the image, and currently available system memory
Each open document has its own list of states
Note: Regardless of the preference setting, when you close a document, all history states (and all snapshots) are deleted from the panel!
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Changing history states
To summarize the two modes for the History panel,
if the panel is in linear mode (the Allow Non-Linear
History option is off) and you click an earlier state,
all the states below the one you click will become
dimmed If you then delete the state you clicked or
continue editing the image with that earlier state
still selected, all the dimmed states are deleted (If
you change your mind, you can choose Undo
imme-diately to restore the deleted states.) If the panel is
in nonlinear mode and you click an earlier state, then
perform another edit, the new edit will become the
latest state, but the prior states won’t be deleted
To change history states:
1 Perform some edits on an image
2 Do any of the following:
Click a state on the History panel A
On the left side of the panel, drag the History
State slider upward or downward to the
desired state
To Step Forward one state, press Ctrl-Shift-Z/
Cmd-Shift-Z; or to Step Backward one state,
press Ctrl-Alt-Z/Cmd-Option-Z
➤ When you choose File > Revert, it becomes a
state on the History panel, and like other states,
all the states preceding it are preserved You can
restore the image to a state prior to or after the
Revert state
A This is after we clicked a prior state, with the History panel in linear mode.
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Deleting and clearing history states
We will presume you followed our advice and put
your History panel in linear mode (you unchecked
the Allow Non-Linear History option) With the
panel in linear mode, if you delete a state and then
resume editing your document, that state and all the
subsequent ones will be discarded from the panel
To delete a history state:
Do one of the following:
Right-click a state on the History panel, choose
in the alert dialog.B
To bypass the alert, drag the state to be deleted
over the Delete Current State button on the
History panel
To delete previous states sequentially without
an alert appearing, click a state, then Alt-click/
Option-click the Delete Current State button as
many times as needed
Note: The Undo command will restore only the
last deleted state
To clear the History panel:
To clear all states (but not snapshots) from your
History panel for all the currently open
docu-ments to free up memory, choose Edit > Purge >
Histories, then click OK in the alert dialog This
command cannot be undone!
To clear all states (but not snapshots) from the
History panel for just the current document,
right-click any state and choose Clear History
This command doesn’t free up memory for
Photoshop, but it can be undone
A Right-click a state and choose Delete from the context menu, then click Yes in the alert dialog
B Because our History panel was in linear mode (Allow Non-Linear History was unchecked) when
we deleted a state, all subsequent states were also deleted.
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Using snapshots
States are deleted from the History panel if any of
the following occur: the specified maximum number
of history states is exceeded; you clear or purge the
panel; or the panel is in linear mode, you click an
earlier state, and then resume editing the document
A snapshot, which is created from a history state,
remains on the panel even if any of the above occur
When you click a snapshot, the document is restored
to the state it represents Both snapshots and history
states are deleted when you close your document
In these instructions, you’ll choose snapshot
options, which affect all Photoshop files; on the
next page, you’ll learn how to create snapshots for
a specific document
To choose snapshot options:
1 Choose History Options from the History panel
menu The History Options dialog opens.A
2 Check or uncheck any of the following options
that pertain to snapshots:
Automatically Create First Snapshot to have
Photoshop create a snapshot every time a file is
opened (this option is checked by default and we
keep it on)
Auto matically Create New Snapshot When
Saving to have Photoshop create a snapshot
every time a file is saved The snapshot will be
named by the time of day it was created
Show New Snapshot Dialog by Default to have
the New Snapshot dialog appear whenever you
click the New Snapshot button, enabling you to
choose options
3 Click OK
A The History Options dialog contains three snapshot options.
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If the Automatically Create New Snapshot When
Saving option is turned off for your History panel,
you should get in the habit of creating snapshots
periodically as you work and before running any
actions on your document If you use the New
Snapshot dialog (the second method below), you’ll
be able to choose whether the snapshot is made from
all the layers in the document, from all the layers at
a particular state, or from just the current layer
To create a snapshot of a state:
Method 1 (without choosing options)
1 Edit your document so it contains the changes
that you want to capture as a snapshot
2. If the Show New Snapshot Dialog by Default
option is off in the History Options dialog, click
the New Snapshot button. If that option is
on, Alt-click/Option-click the New Snapshot
button A new snapshot thumbnail appears
below the last one, in the upper section of the
panel
Method 2 (choosing options)
1 On the History panel, right-click the state that
you want to create a snapshot of and choose
history state becomes selected and the New
Snapshot dialog opens.B
2 Type a Name for the snapshot
3 Choose an option from the From menu:
Full Document to include in the snapshot all
the layers the document contained at the chosen
state
Merged Layers to merge into the Background all
the layers that were visible at the chosen state
Current Layer to create a snapshot of the layer
that became selected when you right-clicked a
history state
➤ To rename a snapshot, double-click the existing
name
A Right-click a state and choose New Snapshot from the context menu
B In the New Snapshot dialog, enter a name and choose which part of the image you want the snapshot to be created from
C A thumbnail for the new snapshot appears on the History panel.