Capture Anomalies

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This page describes specific out-of-the-ordinary problems certain materials might cause during the capture process. For general guidelines in judging image quality, see Visual Assessment of Images.

Only Part of the Image is Out of Focus

Having just part of an image out of focus means one of three things

  • The image is pretty far off center on the document table
    • This could result in one or more edges of the image being fuzzy
    • To fix this, make sure the center of the image is as close as possible to the center of the camera's focus, which is the center of the grid or overlay in the EOS Utility.
  • The camera isn't far enough from the image to take a quality picture
    • This will result in an image that is uniformly fuzzy around the edges (assuming it's centered and has been auto-focused to that same center)
    • To fix this, move the camera up and/or switch to a capture station which allows for a greater distance between camera and document table.
  • The camera isn't centered properly on the document table
    • This will result in a gradient effect across the image, with one side/corner being in focus, with less focus as it approaches the opposite side/corner
    • To fix this, the camera will need to be physically readjusted -- the lens is no longer parallel to the document table. Please see Jeremiah for help with this.

Moiré Patterns

This is a kind of pattern that sometimes appears in digital images, involving rainbow lines or dots showing up against an actual pattern in the object itself. Here are a couple of examples:

Check out her hair:

Moirepattern1.jpg

Look closely at his forehead:

Moirepattern2.jpg

When can this happen?

Only with materials that

  • are off-set printed, and
  • contain patterns
  • Examples may include: posters, pamphlets, booklets, cards

This will NOT effect

  • handwritten materials
  • photocopied materials
  • photographs

How do you keep this from being a problem?

  1. Be aware. It will happen. Know the kind of collections/materials it is likely to impact (more modern collections with more professionally produced materials), and be extra vigilant with examining your captures as you go, to make sure it's not happening.
  2. If a moiré pattern does appear, change the distance between the camera and the object (move the camera or elevate the object) by at least 5-6 inches, and try again.
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