Homebrew PCBs

lcdpublishing wrote:
> ANother thought I had about using the photo-resist boards was the 
> potential for another problem that I don't know if there is a work 
> around or not.
> 
> If you expose a board and the exposure doesn't work out as planed, 
> it is then ruined isn't it?  

If you haven't developed it, you can expose it more if you align
the printout again with what you can see on the resist.

> For example, with toner transfer, if it turns out bad, a missing or 
> pitted traces or whatever else can go wrong, I wash off the toner 
> and do it again and again till it is good enough for what I need.  
> The only loss I have is time and paper.
> 
> However, from an ignorant point of view ( I have never tried this 
> process), if something goes wrong, the board can't be used again in 
> the potoresist process can it?

Not after developing. However, you can scrape bits of resist
off with a scriber and add bits with a resist pen.

> Also, as I don't know what things look like along the way, can you 
> see the traces with the resist on them after developing?  If so, 
> what does the developed photoresist look like?

Undeveloped, the patterns look slightly lighter or darker than
unexposed areas. When developed, you can see the copper.