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Preparing the foil

Using software that generates vector graphics (e.g. Corel Draw, AutoCAD etc.) draw items that you want to etch. All the stuff you want to etch has to be transparent and all that is to stay has to be 100% black; etching will not recognize grey colours, either things are black or transparent, period.

You can either create only one side of the plate and then cover the second side with paint or you can create mirror images by having two foils, one for each side - this method is a bit more tricky but, gives you more flexibility. The most difficult part is  making sure that the foils on both sides are placed correctly and the printed elements line up perfectly when making the 'foils sandwich' into which you will eventually slip the metal sheet. As you see on the picture, I printed small circles around etching area with small dots inside which I use as a reference point. I will use these for the exact pinning later on.

You have more or less full freedom in terms of your design, however you have to stick to few rules in relation to any design:

• what is black on the foil will remain i.e. will not be etched.

• try to stick as many items onto the plate as possible to have the least possible amount of metal to be etched out.

• there is only black and white, no greys. White is etched....black is NOT.

I have tested laser and ink printers, and for etching, ink printers are more suitable. Make sure you use proper acetate (foil); it must be a transparent foil specifically for ink jet printers, otherwise the printer ink may never dry.......well, perhaps it will, but it will take much longer, and will not stick to the foil properly.

Preparing metal plate

Brass ready for spraying

Brass covered with Positiv20

I find this part of work the most difficult and tricky and… time consuming. Photoresist varnish comes in a spray and should be used in as much darkness as possible; however full darkness is not required. The instructions mention that yellow light can also be used, so I use a small 40 watt yellow bulb and point it i completely the opposite direction when applying photoresist. The plate must be absolutely clean! To have a slightly rough surface I sand it with wet 'n dry paper (1000 grade), and the paint will stick better to metal. Finally, apply the varnish on both sides of the brass or copper plate and put it away and let it dry till next day.

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