must be scanned as line drawings (Bitmap) [neither halftone nor RGB!] with at least 800 dpi (preferably 1200 dpi).

The lines must be several pixels thick and should not be interrupted.

In order to save storage space (for a possible dispatch by e-mail) the data files may be LZW or ZIP compressed; never use the JPG format and never reduce the resolution.

example 2.1

The lines are interrupted and some are only one pixel wide. The resolution is too low.

The lines are strongly disrupted due to the JPG format.

The pixels are partly gray instead of black and white: the drawing has been saved as a halftone picture instead of bitmap.

example 2.2

The lines are not sharp: the drawing has been scanned in halftone mode instead of line drawing.

example 2.3

All lines are several pixels wide and the drawing has been scanned in line drawing mode

example 2.4

A line drawing has been scanned in grayscale mode with low resolution (like example 2.2). To get a high resolution bitmap, the resolution has been enlarged and the figure was transformed into a bitmap using a dithering algorithm subsequently. The result is not sufficient.

example 2.5

A good line-drawing had been scanned in halftone with only 8 gray tones.

The initially sharp lines are blurred and fused.

example 2.6

For conversion into another format a dithering algorithm was applied.

example 2.7a

A line drawing was scanned with too low resolution in grayscale mode.

The lines are extremely unsharp.

example 2.7b

A similar figure scanned in bitmap mode with high resolution.

The lines are exactly as in the original drawing.

example 2.8

An excellent line drawing was scanned in grayscale mode.

The lines are unsharp and not all details of the original drawing are visible.

example 2.9

A line drawing was scanned in grayscale mode and subsequently transformed into a bitmap.

As a result of the applied dithering algorithm the black areas are scattered with white pixels.

example 2.10

An excellent India ink drawing on transparent paper was scanned in line drawing mode.

All lines have regular and sharp borders and are several pixels wide.