Adobe Photoshop CS4 - Manual (Page 56)

49 USING PHOTOSHOP CS4
Workspace
Last updated 1/10/2010
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 For the Save Log Items To option, choose one of the following:
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 panel in addition to the Sessions information.
Detailed Includes the text that appears in the Actions panel in addition to the Concise information. If you need a
complete history of all changes made to files, choose Detailed.
Make a snapshot of an image
The Snapshot command lets you make a temporary copy (or snapshot) of any state of the image. The new snapshot is
added to the list of snapshots at the top of the History panel. Selecting a snapshot lets you work from that version of
the image.
Snapshots are similar to the states listed in the History panel, but they offer additional advantages:
• You can name a snapshot to make it easy to identify.
• Snapshots can be stored for an entire work session.
• You can compare effects easily. For example, you can take a snapshot before and after applying a filter. Then select
the first snapshot, and try the same filter with different settings. Switch between the snapshots to find the settings
you like best.