 This is the second in a series of brief tutorials about publishing a family history website. In this article I'll discuss the basics of digitally repairing defects and restoring color and contrast in scans of old photos and other documents. Later tutorials discuss archiving and sharing files, printing, and publishing your family history website.
Image editing software
Once you have a digital image file from your scanner you'll probably need to edit it. Basic editing includes adjusting image size (scaling) and resolution, repairing defects like scatches and stains, restoring color and contrast, and improving apparent "focus", or sharpening.
All of these steps are done with image editing software. Photoshop (Adobe) is probably the best known, professional level image editing software. However, Photoshop is intended for high end applications and as such is expensive and has a very steep learning curve -- probably not suitable for casual users. A related program called Photoshop Elements (Win XP or Mac OSX), also from Adobe, offers most of the functionality of Photoshop in a less expensive and easier to use package.
Finally there's GIMP (Graphical Image Manipulation Program). GIMP is "freely distributed software for photo retouching, image composition and image authoring." Because GIMP is open source (free) and has most of the functionality of Photoshop, it is my first choice for image editing. Some people describe it as "free Photoshop". GIMP is available for most operating systems including Linux.
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Good monitor adjustment or "calibration" is critical to working with digital files and publishing high quality, image-rich family history websites. |
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| Common image defects found in old photos. This scan illustrates 3 defects commonly found in scans of old photos: (1) tears and cracks (lower left); (2) stains (orange/yellow discoloration between windows); and overall low contrast caused by fading of the original. |
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All image editing should be done on a copy of the original scan and the original should be archived in a safe place.
Repair image defects
The first thing you'll want to do is to repair physical defects such as tears, scratches, dust and stains. You should repair defects on the full size images even if you intend to crop for the final website version.
Image defects are repaired using the Cloning Tool, or similar functions, that allows you to copy good parts of the image over defects. Repairs should be made on separate layers to preserve the original background image.
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Restore image color and contrast
The next step is to restore image color and contrast since colors tend to shift and images lose contrast over time. Contrast is lost because dark areas of an image tend to fade faster than lighter tones. The Curves and Levels Tools allow you to apply different levels of adjustment to the image's main tonal areas - shadows, quarter tones, three quarter tones and highlights on a channel (color) by channel basis. These tools also can be used to adjust image contrast. Like the previous step, levels and curves should be applied only to separate layers so that their effect can be changed if necessary.
Set image size and resolution
Set image resolution to about 72 ppi. I generally use an even factor of the original's resolution. So, for example, if the original scan was done at 300 ppi then I'll set the web version at 75 ppi (300/4). Next, set the image size for the dimensions you need on the screen. You can scale images by linear dimensions (inches, centimeters, etc.) or by pixels. I generally use pixel dimensions because these are easier to translate into your website design. It is often very effective to set the web version to the same dimensions as the original.
Sharpen image
Almost every scanned image will benefit from some sharpening to improve apparent focus. Image editors have one or more sharpening filters that can be applied to image layers. One such filter is called "unsharp mask". Always judge the effects of sharpening on images at 100% zoom.
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