Printing the image and Types of Printers
A direct print from your computer to a high quality Laser printer or Ink Jet Printer is required to produce your artwork film for exposing the image onto the SR3000 resist. You can use either Laser Printers or Ink Jet Printers for this process.
Ink Jet Printers do provide a much darker result than lasers but a laser will do the job. Ink jet ink and ink jet film costs more than laser production so you may want to consider the cost. However Ink jets will produce a darker image which in turn will aid production. I’ll explain this further in a moment. Laser media such as UV Vellum (the cheapest option) and Laser Film can be darkened by using darkening agents such as Black Art Spray or the Magic Dark system.
Why the Printed image needs to be black, dark and sharp
The darker the image you use the more light blocking qualities it will have and hence the less light will seep through the image while you are exposing the resist. The less light that seeps through the art area during exposure the faster it will wash out which in turn produces a stronger sharper resist.
The sharper the edge of the art is the sharper the resist edges will be as long as you used a darker print and good compression of the resist and art media. Good compression means pressing firmly together during exposure so no light can leak in from the edges. You achieve good compression with the letralite exposure unit naturally when you clip the blanket on. If you use a flatbed exposure you would use a heavy glass top plate of a vacuum bed.
When using a Laser printer you are producing artwork that is made up of Toner powder laid onto the surface of the printing medium. This creates a mostly opaque coverage. However if you hold the artwork up to the light you will see that light is getting through the black image to a small degree. This is ok as long as you don’t expose the resist for too long. The resist under the black laser printed image is actually getting light on it but not very much and if it is not over exposed it will wash out properly. A Letralite Ultra Violet light exposure unit using a 15watt black light will require 20 seconds exposure with SR3000 Self Sticking Resist or 30 seconds with SSR2000 non self-sticking Resist to produce a good result.
Laser printers use either UV Vellum Paper or Laser Film, both supplied by ProBlast. U.V Vellum is the cheapest media and gives the least quality result but does give you something to work with. We recommend using either Black Art Spray or our Magic Dark product to darken the image.
When choosing a Laser printer we recommend that you buy a HP or Cannon Laser Printer. In our experience no other laser printer works well for the task of producing art film for sand blasting resists. In our experience everyone that has bought a different brand has had problems with the quality of the printed media. We can’t be sure why but expect it has something to do with the toner style or/and the electrical discharge of the toner to the print media. The result is usually that too much light gets through the print making the resist very difficult to wash out. We strongly recommend that you just use Cannon or Hp laser printers.
Most levels of Cannon and Ink Jet Printing will provide a good result but the more you spend the netter the result. We recommend that you set the laser printer to the highest quality print. I suggest you don’t buy the base model but rather the next model up.
An Ink Jet ink is a liquid, which saturates into a paper-based medium such as Vellum and will not provide a workable opacity or good quality sharp surface. You need to use special Ink Jet Art transfer film. Ink jet printers with ink jet film gives a by far the best result for your print media. Ink jets onto ink jet film produce opaque black images that completely block the light making the wash out process faster, stronger and sharper.
There is no need to use Black Art Spray or Magic Dark on ink jet film as it comes out really black. In fact Black art sprat or magic dark would ruin ink jet film.
So Ink Jet film gives a better result however it does cost more in ink and film. But as there is no need for after print darkening and as the resist washes out faster it does become a faster production method which may in your mind out way the higher cost.
Ink Jet film is particularly great for very fine detail work and half tone production.