You need to overcame the limitation of software interpolation (creating larger image with more pixels in from a smaller image)
There are several interpolation methods: linear, bilinear, cubic, bicubic etc. etc.
Chances are Delftship uses the simplest (==fastest but least effective) method.
As a result, the lines get blurry when they are enlarged.

Here is what you can try:

1) Download the "Smart Edge" program from the middle of this page:
http://audio.rightmark.org/lukin/graphics/resampling.htm

This is the best interpolation algorithm currently in existence - the software is an experimental version and very crude
in it's functionality but does an amazing job (compared with the rest of the pack) when it comes to interpolating.

2) Run your original image through this software - enlarge it to the size you are trying to get in the Delftship.
3) Import the enlarged image to Delftship and see if any improvement.

: I have a design that I've imported into Delftship as a background image.

: When I adjust the outline of the control net to trace over the background
: image, I have to magnify the background image to do it. But ... I'm
: loosing a lot of accuracy due to pixilation of the lines of background
: image. The outline of the background image is just too fuzzy to locate the
: outline of the control net accurately ... and my offsets are off about .3
: to .5 inch when compared to scaled values from the hard copy. Accuracy is
: about the same if I use control points or control curves or input station
: offsets ... and fairing just makes it worse and more confusing.

: Any suggestions on how to improve the accuracy?

: Thanks!

: Ken Blanton