photoshop question

hi everybody,

I have problem with photoshop to take a picture,
turn it in grayscale, clean it and then make it a bitmap , first there
is output pixel per inch set at 300 and then frequency line per inch
not more than 70 because I need to etch the metal with ferric choride

I do it but my result I have too much banding in it
what I mean the quality is poor no matter what I start with.

any help appreciate from this wonderfull forum

Not familair with the ferric choride process ( rasist mask? ) but the image size should not be adjusted after all the conversion has taken place. Have you altered the screen angle to improve results. Is your output 300 dpi also? have you changed the shape of your dots? diamond, crosses, ovals????

Stab in the dark!

Mark