by Julieanne Kost
In order to keep a record of commands applied to a file in Photoshop, select Preferences > General and turn on the History Log. You can choose to save the logged items to the metadata (inside of the file), to an external file or to both as well as select a level of detail to record:
• Sessions will only record a minimal amount of information such as when files are opened, saved and closed.
• Concise will record the name of the command (such as Levels or Curves).
• Detailed will record the name of the command and the settings applied (such as Levels, Input: 0, 197, Gamma: 1.48 etc.)