Commons:Restoring images

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So, how exactly do you go about restoring images? (outline for a crash course in image restoration)


  • Who is this course for?
  • What is this course about?
  • Tools
    • Assume Photoshop
    • Get someone to do GIMP?
  • File formats
    • Lossy/lossless
    • Intermediary formats
    • Final formats for Wikipedia
  • Colour & colour spaces
  • Storing images
    • Where? (en / fr / nl / de vs. commons)
    • Something about licenses?
    • Metadata to add?
  • Getting images
    • online
      • LoC
      • Other?
    • scanning images
    • how to

[more stuff goes here]

Where are we going[edit]

Restoring an image is like restoring a house: you have to decide what you're restoring it to.

Things to do[edit]

Possible operations (non-exhaustive):

  • Clean-up: remove dust and scratches, rotate, crop, minor histogram work
  • Retouching: simple clean-up + remove tears & stains, add/repair minor image elements (e.g. corners, non-relevant background), major histogram work (reinterpret colours, treat parts of image differently)
  • Reconstruction: retouching + add/repair major image areas (e.g. body parts, elements only present in other images, interpolation).

Places to go[edit]

Possible targets (non-exhaustive, can be combined):

  • The image as it was first produced (e.g. a photo just after developing, a painting just after being finished).
  • The subject as it is now, minus photographic artefacts (e.g. a photo of a painting or building: remove only dust and scratches on the photo, not on the painting or building) (e.g. a
  • The subject as it would be if you were looking at it in ideal circumstances (e.g. remove double exposures in photos, correct over/underexposure, correct faded colours)
  • A better image (e.g. straighten horizon, different crop, selective sharpening)

Philosophical intermezzo[edit]

When (not) to do what + examples

Principles of restoring[edit]

Garbage in, garbage out[edit]

Start with as high resolution, as well scanned images as possible. Start, if at all possible, with lossless formats.

Small to large[edit]

Start with the smallest operations (e.g. dust), work towards the larger operations (e.g. tears).

Primum non nocere[edit]

Work non-destructively if at all possible (e.g. adjustment layers)

Be a packrat[edit]

Keep all intermediary changes (if at all possible in layers in one file)


Document the different stages of the restoration.

Photography backgrounder[edit]

Old photos are not digital photos[edit]

  • Explain about photographic process?
  • Grain is not noise. Megapixels have no meaning.
  • Techniques: glass negative, emulsion, yadda yadda

How do pictures degrade?[edit]

  • Digitizing: dust, loss of resolution, colour depth, etc. (can a scanner capture iridescence?)
  • Deterioration of the support due to age: cracked glass negative, cracks in emulsion, fading, etc.
  • Physical damage: tears, stains, fading, fold marks, etc.

The process[edit]

Starting out[edit]

Get a rough idea of the final result you're looking for.

Don't do unnecessary work: indicate the final crop and rotation of the image to get an idea of the area you're going to be dealing with. But do not, under any circumstances, work on a rotated or cropped version. Rotate and indicate the crop, then go back and work on the original image.

Low-hanging fruit[edit]

First of all: tackle obvious dust and scratches. Put on some music, we'll be here for a while.

  • Zap using the Healing Brush tool
    • [add principles, techniques & examples]
    • [explain the clone brush / healing brush-two step]
  • Patch Tool for simple stuff
  • Clone Brush

Out, damn'd spot! out, I say![edit]

Even when it all looks clean, it isn't. Step two: remove non-obvious dust and scratches.

  • Levels adjustment layer to enhance contrast
  • Over the top sharpening to bring out unnatural image elements
  • Clean at high magnification (200% - 400%), zoom out to 100%, clean again, zoom to 50%, clean again. Lather, rinse, repeat.

Fill in the blanks[edit]

Sometimes the information is just gone.

  • [cloning, techniques, etc.]
    • Dealing with texture

Living on the edge[edit]

Edges are often hard:

  • wear & tear
  • fingerprints
  • spots & stains
  • peeling/cracked/... negatives

Avoid doing unnecessary work: clean up right up to the major problem areas, then decide on a crop area and do the rest.

Use a crop mask to preview the crop.

Colour and contrast[edit]

  • The Histogram Is Your Friend™ -- today is Better Know A Histogram Day
  • Tools:
    • Levels
    • Curves
  • General adjustments
  • Local adjustments
    • Vignetting, fading and folds
    • Large stains

Stuff to fit in there somewhere[edit]

  • Stains and discolorations
  • Sharpening
  • Despeckling
  • FFT

Final prep[edit]

  • Cropping / rotating
  • Naming