I am currently working on a portfolio for school. I would love to export image files that show lineweights perfectly. I have used dwg to pdf but i'm not really happy with the picture quality. If anyone has any suggestions, it would be much appreciated.

you can type saveimg command and if save image dialogue box appear choose bmp and click ok.

I am not sure which Autocad version you are using . But above 2008 version Autocad has included the printer for Publish to webjpg.pc3 . Use that printer to print your drawings it would take care of .CTB file that you may be using, so you should have no issues with lineweight etc.
 
Secondly you can select the resolution you would prefer to get more clarity. Just be aware thet Higher resolution the higher the file size.
 
 
Tom
www.indovance.com

Thanks Tom.
 
I was playing with that yesterday and it worked pretty well for me.
Another thing that i found is 'primo pdf' if you're ever interested in getting really good pdf files exported from autocad, you can download primo for free.
I think you'd be surprised at the lineweight quality and clarity.
 
Chris