Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcsun!ukc!acorn!moncam!emmo
From: emmo@moncam.co.uk (Dave Emmerson)
Newsgroups: sci.electronics
Subject: Re: PCB making ?
Summary: Depends on track thickness
Message-ID: <317@marvin.moncam.co.uk>
Date: 19 Dec 89 19:53:45 GMT
References: <2652@servax0.essex.ac.uk>
Organization: Monotype ADG, Cambridge, UK
Lines: 37

In article <2652@servax0.essex.ac.uk>, zotog@SunLab14.essex.ac.uk	 (Zotos G) writes:
>[] 
> 
> Is it posible to photocopy the piece of paper with the track layout on a
> clear plastic film used on overhead projectors and use this as the film
> plased on the premade positive photoresist PCB and then to expose that 
> in UV light ?
> 

Very unlikely. Even if you can get enough density in the image area,
it will tend to be grainy. Also, you may not get 1:1 copies

You need to use 'Ortho Lith' photographic film, in a lith developer, or
at least a VERY high-contrast developer. You can handle this in red
safelight and dish develop it quite easily.

Better, Draw it 2:1 on white paper, with a dense black pen, and get it
camera'ed at a specialist PCB photo house for about 15 pounds for 
a 10 x 8 inch final positive. 

Even better, buy some of the transfer sheets made for the job, or even
the proper black crepe tapes + pads from (say) Maplin Electronics.

Most of us start out this way, you'll only get what you pay for.
Another possibility, if you have wide (>0.05 inch) tracks, is to use
presensitised silk screens, and PRINT your circuit onto plain copper
clad board, if you intend to make a few of them.

> Thanks in advance.
 
  You're very welcome.
> 
> P.S. Please forgive my English, as I'm Greek. 

  Your English is much better than my Greek!

Dave E.