Keep in mind you are working for an impression, so all artwork needs to be in negative, this is especially important for work that includes lettering. I usually try to think of it this way, everything that is black in the artwork, will be raised area when impressed.
Your designs could come from all kinds of sources.

• Drawing
If you have the ability to draw, use pen & ink for your designs.
Strong black & white is required, this is known as ‘line art’ in the printing industry. You can also draw in pencil and have the resulting drawing photocopied to make a high contrast drawing.
• If you are proficient on the computer, using a graphics program, you could scan a drawing and convert to a high contrast drawing. Or if you want to do the complete artwork in a drawing program like Adobe Illustrator or Corel Draw, make sure the line you use is no thinner than 1 pt (= 0.5mm - 0.02")
• Any picture could have potential, try playing around with a photocopier, changing contrast settings.
• Look at found textures, which could include maps & charts, newspapers, letters, wing dings.
• There is also a lot of copyright free art available for artists, look at ‘Dover’ books and crafters motif sheets.

All these methods are indirect, they have to be transferred to an overhead transparency (OH) before they can be used to make a plate.

You can do this by printing your design onto OH Transparency material using a laser printer through your computer, or get a copy centre to make a laser copy for you. Check that the image on the OH transparency is nice and black, not grey and partially see-through.
You can also draw onto the OH Transparency directly, using permanent markers, or pen & film ink. Make sure the markers are for use on film and very black so no light can seep through.

Another possibility is direct exposing materials onto the plates, with no artwork being done.
As long as the materials do not damage the light sensitive layer of the plate and are sufficiently solid to block out the light, they should work fine. Think of paper cutouts, maybe skeletonised leaves etc. I have not tried these myself, so I can’t comment on their suitability. Try it and see!

The plates can be exposed using different UV exposure methods:

• Sunlight. Not very easy to control and determining the exposure times from one day to the next, or through different seasons.
• Halogen desk lamp. These easily obtainable lights work very well, slower than a UV tube exposure unit, but this could well be an advantage in fine-tuning the exposure times. Get one with a 50-watt bulb in it. This is what I use for small jeweler sized plates, the largest plate I’ve made using this light, was 100 x 100mm (4”x 4”)
• UV exposure box. This is fairly easily constructed, it is basically a light box using special UV tubes or an UV Sunlamp. If you are thinking of using these tubes, remember they have a service life and get weaker after that expires. Check with the manufacturer what the life of your lamps are.
• Then there are the professional exposure units, used by printers and art departments. Try your test-strip to determine the exposure time if you have access to one off these.

Make a test strip on OH transparency film, using a strong line design & about 5" long.
Here’s one I’ve used, you are welcome to use it if you want.
When designing your test strip, don’t make the lines too thin, they could lift off the plate. Although some of the areas of your test plate will not work very well because of under exposure, some areas will be usable as textures so, parts of the plate can be used for your designs.

This can be easily made up using readily available materials:

1. Some thin board, craft wood or masonite, about 5 cm (2”) larger than the maximum size of your artwork (for the 4”x 4” plates I use a 6”x 6” piece of board)
2. A piece of bubble wrap or thin foam to act as cushioning, bubbles side down on the wood, smooth side up, taped to the wood.
3. A piece of 2mm glass the same size as your board
4. 4 large bulldog clips
An easy way to get these materials together, might be to buy an inexpensive photo frame from a $2
shop.

The plates can be handled safely in any non-UV light, fluorescent tubes are fine. Just keep them out of sunlight or have them near any UV light source.

Please note the exposure times are a guide only, you might have to do the test strip 2 - 3 times to get the optimum exposure for the light you are using. The times below are for UV Tubes, if you are using a 50W Halogen light, use 1 minute increments ISO 20 seconds per exposure.

*Cut a 14 cm (5.5") strip off the plate. Remove the cover film from the plate and position your artwork on the plate, with the printed side touching the plate. Position the plate in the centre of your exposure frame, cover with the glass sheet and position the bulldog clips so they keep away from the design itself.
*Cover the plate with some heavy card for all of its length except the last 2 cm (3/4")
Set your timer for 20 seconds, switch on your UV light source and expose for that length of time.
*Switch off the light, reset the timer for another 20 seconds, move the cardboard another 2cm (3/4”) and expose again. Keep on doing this until the whole strip has been exposed. The very last exposure will have only received 20 seconds of light, the next 40 seconds etc.
*Wash the plate as described below and judge the perfect time for your light source. Look for very smooth, crisp edges and a complete wash out, right to the metal. Over-exposed areas will not wash out well, or not at all, under-exposed areas will wash away too much, leaving softer, rounded edges and wider lines than the original design's.

As a guide, for my Halogen desk lamp I use a total exposure time of 7 minutes.
For an exposure unit with new UV tubes, I use 1.5 minutes.

1. Prepare your artwork on Overhead projection film.
2. Brush talcum powder on the film using a very soft brush. Apply to the side that will be in contact with the plate surface, brush off excess. This will prevent the film sticking to the plate during exposure, when there will be some heat generated.
3. Cut the plate, using a drawknife and metal ruler, or metal shears.

Wipe excess water off the plate with the natural sponge and dry the plate surface in
front of a fan heater set on medium, with the plate on its edge about 30cm (1’) away
from the heater for about 5 minutes. Check there is no stickiness.

Post expose the plate for the same amount of time you used for the initial exposure.
This will harden the plate all the way through.

Brush a little vegetable oil over the whole plate, this stops it from drying out and
cracking.

To use with metal clay: brush on vegetable oil as you would with other texture plates.
For use with polymer clay: use corn flour (cornstarch) as you would with any other stamp.