[Resizing image loses clarity]

I'm having a problem using the resizing tool.

 

What I'd like to do is scan a simple line drawing, mostly an outline of a possible logo. Then use Affinity to reduce the image to a few selected sizes and then print them out. 

 

The problem is when I use the resize box, switch from pixels to inches, and tap the resize button all the lines in the image on the canvas that were smooth become very jagged. And they print that way as well. 

 

I guess I'm missing a step, but after going through all the tutorials I can't what I'm screwing up. 

 

BTW...the tutorials are great, easy to understand and makes using Affinity really enjoyable. 

 

Allan