Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "hjf2k2" <drgenio@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, July 25, 2005 3:42 PM
Subject: [Homebrew_PCBs] black photoresist masters - darkening


> Hi all, I'm still working on the serigraphy emulsion system. I think I
> need to increase the exposure time to burn the emulsion a little
> more. The problem is that I'm using transparencies with toner as
> masters, and toner, even from a new cartridge, is not totally black.
> So I went to the serigraphy shop and found a very interesting product:
> toner darkener. It's actually called toner blackener in my language
> (ennegrecedor de toner), but I found it as darkener on google.
> It's a spray, cheap, about $7 for the local brand and $15 for an
> european brand, which the guy told me is used to make masters for
> offset prints. So I bought that one and sprayed it on a transparency.
> the effect was INSTANT, it dried up in a few seconds and the toner is
> now totally black, even under the sun!
> So to all people using photo resist, this might be an interesting
> option. Also to people who use toner transfer, maybe this will help
> with thin lines? I didn't see if it leaves residue as the test
> transparency I used had no transparent edges.

A similar technique I've heard of is to expose the transparency to some
solvent fumes.

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller



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