How to scan a game box last updated 2007-01-23

Scan your board at a resolution of 300 dpi (dots per inch) and store the result as a set of PNG files. Several files are needed if the material being scanned is larger than the scanner's glass pane. The fragments will be assembled during the compositing step.

To produce high quality scans, you should try to minimize white noise and scanner artifacts, and you should avoid moiré patterns and JPEG artifacts.

Don't store your intermediate files as JPEG files, to avoid the accumulation of errors.
1 - Original image (shown at normal size and enlarged 200%).
2 - Same image, saved as JPEG using Paint.
3 - After ten consecutive saves (note how the red "4" is discoloured).

JPEG artifacts

You should not save your intermediate files as JPEG files. Use PNG instead.

JPEG, as a lossy data compression format, suffers from generation loss: repeatedly compressing and decompressing an image will cause it to progressively lose quality. This is in contrast with lossless compression formats such as PNG.

Don't use JPEG as the output format for your scanner either. If your scanner doesn't support PNG as an output format, use BMP instead.

Moiré patterns may appear if you scan at a resolution lower than 300 dpi.

Moiré

Moiré patterns are caused by interference between the sampling grid used by your scanner and the halftone screen used by the printing press.

Usually you won't see moiré if you scan at a resolution of 300 dpi.

If you still have moiré patterns at 300 dpi, you may want to activate the descreening filter that is usually part of your scanner driver software. The descreening filter is dedicated to the elimination of moiré patterns from printed material.

White noise and scanner artifacts

If your scanner produces artifacts such as horizontal bands, or excessive white noise, you can sometimes decrease their effect by averaging several scans.

To average two scans, load the two images in your bitmap graphics editor as two different layers of the same image, then set the top layer transparency to 50%.

Distorted and discoloured areas

When scanning large folded paper maps, make sure the material being scanned is firmly pressed against the glass pane by stacking a pile of books or magazines on top of it.

When scanning a large board fragment by fragment, you should always arrange large overlapping areas between the different fragments. That's because usually the part of the material that lies at the edge of the glass bed will be slightly distorted or discoloured, and so will have to be discarded eventually. Large overlapping areas will make the compositing easier.

It's best if pre-cut counters appear to be lit from the top or the left.

Pre-cut counter sheets

When scanning relief material such as pre-cut counter sheets, most scanners will cast a shadow on the reliefs as the light source moves across the glass pane. It is better if that shadow is consistent with the lighting convention used in ZunTzu: the top and left edges of the counters should be lighter than the bottom and right edges. You can achieve that by choosing the correct orientation for the counter sheet on the scanner glass pane.