Line Scale in linear Graph

Hi.
I have some charts which contains 7 different lines and each is illustrated based upon two 1200 column of data. I can't make them clear by color due to black and white printing process. The only way for me is to change "line style" to dash, dash line and so on. Unfortunately excel doesn't understand to scale line type and shows all lines the same, which is because of numerous data. Is there any "Scale" setting for this problem like what we can do in Autocad ???
Please help me....

Anybody knows how to deal with dense data series in linear graphs ????

Weird............!

could you please share me the data so that i could work over it?