Raster frames work best if they are close-ups of a recognizable image.
You can preview a particular image by using a graphics program such as
Adobe Photoshop or JASC Paint Shop Pro.
Load in the graphic file. It can be in any
supported format, such as BMP, GIF, or JPG. In the example below, we'll
use a JPG of the Mona Lisa:
 Check
the size in pixels of the graphic. In the case above, it is about 300 x
300 pixels. A typical LD2000 raster is 60 pixels x 60 lines, so this means
that 300/60, or 5 source pixels will blend into one raster pixel.
Use the "mosaic" or similar function to
divide the graphic into blocks. Remember that you want to end up with 60
blocks horizontally and 60 blocks vertically:
 The
final result gives a good idea of how detailed your raster frame will
appear:
 In
this particular image, the eyes are problem areas. The left eye captures
only part of the pupil and iris, and so appears as a slit. In the right
eye, the pupil and iris blend into the eye socket shadow, to form a big
dark blob.
The best solution is to crop the
photo so you can get more detail. Here, we've cropped just the eyes, nose,
mouth and chin. The Mona Lisa is still recognizable, but as you can see,
the same 60 x 60 mosaic gives much better detail in the eyes:
 The
close-up, cropped version will be a more successful laser raster scan.
Incidentally, note how the laser raster actually smooths out the colors,
making the mosaic effect not as apparent. (Of course the scan lines are
more apparent. But then you can't have everything!)
 |