What was your light source? With the board not flat, perhaps light
leaked under.
How do you make the transparency? Do you print mirror image and place
it image side down, or print normally and place image side up?
Does the vacuum system have a stiff cover that presses down on the
transparency, like glass or plexi, or a thin flexible plastic sheet?
BTW, due to a problem member in the past, all photos are moderated.
Yahoogroups doesn't give me an option, as it does with messages, to
only moderate new members on photos. So just post a photo and I'll get
an automatic email telling me there is a photo waiting for approval.
I'm only human, so it may take a day or two (at the worst) to appear.
Steve Greenfield
--- In Homebrew_PCBs@yahoogroups.com, "Paul Newman" <vk4apn@...> wrote:
>
> Have just posted a picture under vk4apn. There is a noticable ripple
> effect on the straight lines. The image was crisp and straight and
> made using vacuum lightbox. I made some other smaller boards at same
> time and they are perfect. The PCB material is 0.8mm kinsten. It
> looks like board itself is not perfectly flat as ridges conincide with
> etched pattern. First time to use thin board so am I doing something
> wrong?
> Paul vk4apn
>