Photo Restoration of Multiply Scanning
( Scanning Pictures With Embossing )
Results of multiple scanning
It is well known that the utilization of powerful side lighting (the kind of lighting applied in a scanner) emphasizes the surface structure of the original.
Scanner lamp position
in relation to the scanned surface
Texture light reflection
For example, photographers manage to dramatically reduce or even totally eliminate defects using several light sources while reproducing old cracked-up photos and paintings. A photographer moves lights around getting ready to take shots of the original, selecting the best lighting position.
There is only one source of light in the scanner. What should we do in this case? How can we fit several lamps in the scanner lighting up the photo from different directions? Let's make a better decision
Let's scan the picture several times (each time at a different angle to the scanning direction) and then superimpose the scans using translucent Photoshop layers.
"scanning scheme" (Arrows point out the scanner lamp movement direction)
"Photoshop layers" (read more on how to do this on the insert)
The result of these manipulations will be the same, as if we light up the original with several sources of light. The lighting direction in the scanner coincides with the lamp movement direction. So, to light a picture in the desired direction you just need to position it correctly along the scanning line.
Photo with regular square embossing. The scanning was carried out in two steps at 45° and 225° angles respectively; scanning down any of the picture sides would inevitably leave vertical lines on the scan. Another option may be scanning in four steps at 90° down the picture sides. However, this will increase the work load in the scans alignment, and the visual sharpness of the resulting image will be lower.
The superimposed image was obtained by pasting the layers with opacity set to 50% in the Normal mode.
Let's look at the result. Wow! Almost all surface defects are gone as well as all protuberances and surface roughness casting shadows. However, all other defects (and what is the most important - the details) are still there.
It will be much easier to eliminate the remaining "flat" defects, and the result will definitely be of a better quality.
- Analyze the image. Generally, a two-step scanning (with a 180° rotation of the picture) is sufficient. Please, note that the deepest elements of embossment texture should be positioned at the 90° angle to the scanning direction. Avoid scanning the picture along the texture elements.
- Disable all automatic settings of the scanner: the scanning parameters should be identical for all the scans.
- Place the obtained scans within one file frame.
- Make sure the layers of the picture coincide. Setting the Difference overlay effect for the top layer is particularly helpful, after this you can rotate/move it around (Edit/Free Transform) until the superimposed image is at its darkest point. You can also find two easily identifiable contrasting spots in both layers (keep in mind: they need to be as far as possible from one another). Set the Opacity of the top layer to 50% with Normal overlay mode. Superimpose the selected spots.
- To get the double exposure effect, set the Opacity of the top layer to 50% (the overlay effect should be set to Normal).
- In some cases it is better to use Darken or Lighten modes instead of the Normal mode. They can help darkening the flashy areas or lighting up the crack shadows. *) If three or more scans need to be superimposed, their respective opacities should be set to 33%, 25%, etc.