This is a design schetch for raw image support in Photovault

Requirements

  • If the original image is a raw image Photovault can recognize it as such, create a thumbnail and display it correctly
    • All raw image formats recognized by dcraw should be handled (#65)
  • Photovault must be able to read metadata from raw images as well - implemented
  • If an error happens during raw image reading this must be reported properly to user

Raw conversion

  • User must be able to specify raw conversion parameters, including
    • Camera color profile (#66)
    • White balance settings: either camera default (#67), automation (=dcraw automatic), any of camera presets or manual setting
      • Manual white balance can be set as color temperature + potentially fine tuning, at least for green channel -implemented
    • Exposure correction as EV steps
      • Default level is set so that log average brightness is 18%
    • Highlight compression settings
    • Black level settings
    • User can control these from an dialog and can see interactive feedback in a preview image (#68)
    • The raw conversion settings are stored in database
  • It must be possible to change settings of several selected photos at once (#69)
    • In 1st version it is OK that no feedback is given. In future there should be possibility for viewing a preview image also in these cases

Instance handling

  • Raw conversion used must be stored in thumbnail/copy instances as well.
  • When changing raw conversion settings, the old thumbnails & copies must be deleted after copy of similar quality that has been created with new raw settings is available. (#70)
  • User must be able to specify that a converted copy at full resolution (or 1/2 respolution?) is maintained in a given volume. If such copy is available it is used for viewing (#71)
    • The copy is also used for exporting if the quality is high enough (e.g. bit depth and color space of exported image is the same). If this is not the case, the raw image is directly converted to exported image
    • If the copy is of 1/2 respolution, the zoom settings are anyway show like they would be shown for full respolution image. If user selects to use 100% zoom the raw image is read and used instead.

Raw workflow

Raw Conversion Representation

  • White point
    • Absolute linear value that is considered white
  • ICC profile
    • ID of the ICC profile to use
    • Flag if embedded profile is used
  • EV correction
    • The EV correction setting (double)
  • White balance type
    • Automatic, camera or manual
    • This is not communicated to dcraw, chnalle multipliers are always read from database
  • White balance multipliers (3 doubles)
  • Daylight multipliers (3 doubles)

Attachments