Developing the pre sensitized pcb.

You’ll need:
 

• a box which could be filled with the development fluid
• 1 Litre warm water (20°)
• 10g Natriumhydroxid NaOH

This is the pcb after the exposure. You could see recognise the circuit path a bit

Water should be 20°. The higher the temperature the shorter the developing time. With cheap pcb material and 25° the developement time could be under 1 second! That’s very bad! ;-)

TIP: When the NaOH is mixed with the water... the chemical reaction heads up the water, so that a thin plastic case could be damaged!

If the NaOH is fully dissolved you can put the pcb in the water.
Use a soft brush to remove the pre sensetised surface.

Remove the developer by washing...

This is the pcb after developing. The conductor paths are more clearly.