Turning A Photo Into A Sketch

Hi,
1. Attached are some sketches which I once did in PhotoPaint X4.
2. The original was not a good candidate for a sketch. It does not have
strong lines except for the contours of the building.
3. You can also prepare the raster image for a sketch by increasing
contrast and also by using Unsharp Mask.
.. Let me add that there is an additional advantage if you do
this on a layer (aka object). You can then vary opacity, increase contrast,
use Curves, etc..
Phil