blue pcb
Dear Ser!
What is "blue PCB", You have.
I suppose, it is pcb with photo-resist coating, with blue self-adhesive protecting
plastic sheet over."Bungard" is manufacturer of such boards, and I use lot of them.
Before You make exposure to UV light, You must pell-off protective blue sheet.
For exposing, you may use "black-light" lamp. (fluroscent lamp as for
fake monney detection devices).It is long-wave UV light, but ideal for photo resist,
and not harmfull fo eys.I use 3 x 8W on distance 100mm, and 4 Hours exposure.
All is critical, exposure, developing and etching.You must experimenting.
I cut narrow piece of PCB material, and expose (hiding with opaque material),
for 5, 10, 15, 20, minutes, develop and etch, to see results.
NaOH solution is used for developing, but special developer is better,
and safer in any way.
T.D.