--- In
Homebrew_PCBs@yahoogroups.com, Alan King <alan@n...> wrote:
> Stefan Trethan wrote:
> > What i wanted to ask before the huge picture file diverted me:
> >
> > You wrote you used aceton for rubbing off the toner.
> > In the blackened areas, did the acetone solve the epoxy and mix it
with
> > toner?
> > or what else?
> > that looks not good and it would be a reason not to use acetone for
> > rubbing.
> > I use laquer thinner and had no such effects.
> >
> Why do you jump to this from a little bit of black left on the
board?
> You're likely using several times too much solvent if you're getting
> your board spotless. Or your board composition is different from
his so
> is more slick and washes more easily. Or any of a half dozen other
more
> sensible reasons than the acetone is melting the board to any degree
> worth noticing..
It only has to slightly attack a thin layer to result in toner mixing
into the board. Acetone can and will attack epoxy.
> Even if it actually did what you're guessing it wouldn't be a cause
> for concern at all since it evaporates fast and isn't going under the
> traces. But it's not, it's just drying and leaving the toner
residue on
> the board.
It can cause problems, as toner generally contains carbon black which
is conductive. In most circuits this may not cause a problem, but in
high impedance and RF circuits it can very well cause problems.
> >Please delete the tiff image, the jpeg has no data loss and safes
> LOADS of
> space.
>
> You should note for reference that JPEG is actually a lossy
> compression. Fine for general pictures like this but for anything you
> really need no degradation it's not the right format.
I'm confused as to what you are objecting to. You acknowledge that JPG
is fine for this picture. He does mention GIF for line art. Stefan is
absolutely correct, there is no reason to use up the limited File
space for an uncompressed 3 meg TIFF when a 100K JPG will do. The
image as a JPG looks fine to me.
Here's an article on web graphics I wrote a few years ago for the
newsletter of a local computer club.
http://www.polyphoto.com/upchug/webgraphicstut3/index.htmlSteve, the moderator