Photoshop

Work with the History palette

You can use the History palette to jump to any recent state of the image created during the current working session. Each time you apply a change to an image, the new state of that image is added to the palette.

For example, if you select, paint, and rotate part of an image, each of those states is listed separately in the palette. When you select one of the states, the image reverts to how it looked when that change was first applied. You can then work from that state.

You can also use the History palette to delete image states and, in Photoshop, to create a document from a state or snapshot.

To display the History palette, choose Window > History, or click the History palette tab.

Photoshop History palette

A.
Sets the source for the history brush

B.
Thumbnail of a snapshot

C.
History state

D.
History state slider

Keep the following in mind when using the History palette:

  • Program-wide changes, such as changes to palettes, color settings, actions, and preferences, are not reflected in the History palette, because they are not changes to a particular image.

  • By default, the History palette lists the previous 20 states. You can change the number of remembered states by setting a preference. Older states are automatically deleted to free more memory for Photoshop. To keep a particular state throughout your work session, make a snapshot of the state.

  • Once you close and reopen the document, all states and snapshots from the last working session are cleared from the palette.

  • By default, a snapshot of the initial state of the document is displayed at the top of the palette.

  • States are added to the bottom of the list. That is, the oldest state is at the top of the list, the most recent one at the bottom.

  • Each state is listed with the name of the tool or command used to change the image.

  • By default, when you select a state, the states below it are dimmed. This way you can easily see which changes will be discarded if you continue working from the selected state.

  • By default, selecting a state and then changing the image eliminates all states that come after it.

  • If you select a state and then change the image, eliminating the states that came after, you can use the Undo command to undo the last change and restore the eliminated states.

  • By default, deleting a state deletes that state and those that came after it. If you choose the Allow Non-Linear History option, deleting a state deletes only that state.

Revert to a previous image state

 Do any of the following:

  • Click the name of the state.

  • Choose Step Forward or Step Backward from the History palette menu or the Edit menu to move to the next or previous state.

Delete one or more image states

 Do one of the following:

  • Click the name of the state, and choose Delete from the History palette menu to delete that change and those that came after it.

  • Drag the state to the Delete icon  to delete that change and those that came after it.

  • Choose Clear History from the palette menu to delete the list of states from the History palette, without changing the image. This option doesn’t reduce the amount of memory used by Photoshop.

  • Hold down Alt (Windows) or Option (Mac OS), and choose Clear History from the palette menu to purge the list of states without changing the image. If you get a message that Photoshop is low on memory, purging states is useful, because the command deletes the states from the Undo buffer and frees up memory. You can’t undo the Clear History command.

  • Choose Edit > Purge > Histories to purge the list of states for all open documents. You can’t undo this action.

Create or replace a document with an image state

  Do one of the following:

  • Drag a state or snapshot onto the New Document button . The history list for the newly created document will be empty.

  • Select a state or snapshot, and click the New Document button. The history list for the newly created document will be empty.

  • Select a state or snapshot, and choose New Document from the History palette menu. The history list for the newly created document will be empty.

  • Drag a state onto an existing document.

To save one or more snapshots or image states for use in a later editing session, create a new file for each state you save, and save each in a separate file. When you reopen your original file, plan to open the other saved files also. You can drag each file’s initial snapshot to the original image to access the snapshots again from the original image’s History palette.

Set history options

You can specify the maximum number of items to include in the History palette and set other options to customize the palette.

  1. Choose History Options from the History palette menu.
  2. Select an option:
    Automatically Create First Snapshot
    Automatically creates a snapshot of the initial state of the image when the document is opened.

    Automatically Create New Snapshot When Saving
    Generates a snapshot every time you save.

    Allow Non-Linear History
    Makes changes to a selected state without deleting the states that come after. Normally, when you select a state and change the image, all states that come after the selected one are deleted. In this way, the History palette can display a list of the editing steps in the order that they were made. By recording states in a nonlinear way, you can select a state, make a change to the image, and delete just that state. The change is appended at the end of the list.

    Show New Snapshot Dialog By Default
    Forces Photoshop to prompt you for snapshot names even when you use the buttons on the palette.

    Make Layer Visibility Changes Undoable
    By default, turning layer visibility on or off is not recorded as a history step and therefore can’t be undone. Select this option to include layer visibility changes in history steps.

Set Edit History Log options

You may need to keep careful track of what’s been done to a file in Photoshop, either for your own records, client records, or legal purposes. The Edit History Log helps you keep a textual history of changes made to an image. You can view the Edit History Log metadata using Adobe Bridge or the File Info dialog box.

You can choose to export the text to an external log file, or you can store the information in the metadata of edited files. Storing many editing operations as file metadata increases file size; such files may take longer than usual to open and save.

If you need to prove that the log file hasn’t been tampered with, keep the edit log in the file’s metadata, and then use Adobe Acrobat to digitally sign the log file.

By default, history log data about each session is saved as metadata embedded in the image file. You can specify where the history log data is saved and the level of detail contained in the history log.

  1. Choose Edit > Preferences > General (Windows) or Photoshop > Preferences > General (Mac OS).
  2. Click the History Log preference to toggle from on to off or vice versa.
  3. In the History Log Options panel, choose one of the following options:
    Metadata
    Saves the history log as metadata embedded in each file.

    Text File
    Exports the history log to a text file. You are prompted to name the text file and choose a location in which to store it.

    Both
    Stores metadata in the file and creates a text file.
    Note: If you want to save the text file in a different location or save another text file, click the Choose button, specify where to save the text file, name the file if necessary, and click Save.

  4. From the Edit Log Items menu, choose one of the following options:
    Sessions Only
    Keeps a record of each time your start or quit Photoshop and each time you open and close files (each image’s filename is included). Does not include any information about edits made to the file.

    Concise
    Includes the text that appears in the History palette in addition to the Sessions information.

    Detailed
    Includes the text that appears in the Actions palette in addition to the Concise information. If you need a complete history of all changes made to files, choose Detailed.