Homebrew PCBs

ghidera2000 wrote:
> I actually have an inkjet already. I emailed MG Chemicals and asked 
> about using inkjets instead of laser. They replied and said that 
> inkjet inks aren't UV opaque and don't work well for the process. 
> So, since I was already strongly considering buying another laser, I 
> said what the hell and picked this one up.(I print so infrequently 
> that my inkjet cartridges keep drying out on me so toner/developer 
> is cheaper in the long run).
> 

Inkjet black images on transparency film is extremely opaque to UV-A radiation. 
In fact I find it almost impossible to do overexposure with my Epson Stylus and 
Epson transparencies. I do not have a UV photometer to give you actual 
absorption figures but its definitely more than adequate. The Epson ink is dye 
based (soluble organic colorants) and actually looks deep red through bright 
light. HP & Lexmark inks are pigment based (carbon black dispersion) and are 
also extremely opaque to UV. The problems arising with some inkjet printers used 
to create PCB photomasks is micro pinholes, banding and ink splattering. If you 
find good inkjet system that does not have these problems then you are set.