I hope somebody can help me with what I imagine is a very simple issue that I can't figure out as I'm completely new to all of this.

I am trying to create designs for a laser cutter in order to make wood/acrylic stamps which I can use for my leatherwork. I have designed several, traced the bitmap etc, created the paths, and set two different colours so the laser knows to engrave black and cut red lines.

My problem is this: I have created the colours the wrong way around. I have realised the stamps will be the mirror of what I want on the leather, and so it's going to compress it in the exact opposite places.

Is there a way I can simply invert the two colours in my designs, changing black to white and vice versa. I have tried searching for the answers and have tried various effects, filters, extensions. But I always end up with only pure white rather than the two colours inverted. I can of course invert the colours easily in paint, but I then have problems re-adding the red cut line in Inkscape with one of the colours bleeding either side of the red line which is going to make more work for the laser unneccessarily.

Here is an example. On the left is what I currently have. On the right is what I need (I inverted this in paint).

Untitled3 by Hamish Odinson, on Flickr

Any help/advice for a complete tech beginner would be very much appreciated

Cheers,
Hamish

Welcome aboard!

Haven't worked with cutters/engravers myself, trying to understand the problem.
You say that the engraver takes filled paths -"areas"- as an input istead of the cutter which follows the red path?
And, you have traced the raster image by the trace bitmap option?
And want to avoid retracing the image with inverted colours.

Well then, an easy solution would be duplicating the red path (Ctrl+D) and
combining it with the black path (Ctrl+K). Depending on path direction it may not look right at first.
If all rendered with the same colour then you need to select a segment of the subpath which was the duplicant before -selecting the two bottom-most nodes would do- and reversing the path will solve.

This may help explain it a bit more.


And by the way, you have a nice gallery!