Improving Lines in High Res Multi-Lined Coloured Plot

[jemma]

I have a multi-lined coloured plot in which I need some lines represented by dashed lines ('linestyle', ':') and I also need my plot to be quite a high resolution (dpi) for publication reasons (print -r600 -dtiff myfile.tif). So this works fine but when I open the tiff file with high resolution the lines just appear pale instead of dashed when inserted into MS Word (unless you zoom right into the lines). I tried using 'linestyle', '--', too but this looks even more just like a faded but solid line.
Any suggestions?
Thanks.

 

[jhae2.718]

If you have your plots, you may want to try: http://www.mathworks.com/help/techdoc/creating_plots/f3-84337.html#f3-99772