In this article we will explain the different types of print media that can be used for printing artwork for the exposure process of PhotoMask resist and we’ll explain why the more opaque black artwork is better for the production of great quality resists. This in turn should help you decide which print media to use.
There are three types of print media to choose from. Vellum and laser film which require laser printers and Ink Jet film which requires ink jet printers. Ink Jet gives the best black print and Vellum gives the least black print. Vellum is the cheapest option whilst Ink Jet is the more expensive option. All types of media will work for exposing your artwork onto PhotoMask resist but you will get the best results from Ink Jet.
Laser printers use laser toner which is a powder ink whilst Ink jet printers use a liquid ink. Liquid inks give a more opaque image and so give the best resist development result.
If you hold a vellum or laser printed artwork up to the light you will see that light does get through the toner which means during exposure the art area of the film (the blackened bits) is getting light saturation very slightly during the exposure time. Vellum gets more than laser but they both get some light. This simply means that thin areas of artwork are getting light leakage and will take longer to washout. The longer it takes to wash out the more saturated the resist and the less sharpness in the resist integrity. To understand this better see the article SR3000™ - What Is It and How Does It Work?
Ink Jet film with an ink jet printer gives the blackest black and so protects the artwork area best during exposure so you get no light seepage onto the art area, meaning the developed resist washes out faster resulting in a sharper, stronger resist.
In conclusion, we recommend using Ink Jet film and ink jet printers. This is the standard in the Screen Printing industry which uses photopolymer emulsions to produce their screens. You get a better and more consistent look. The down side is that it is the most expensive media. For those with budget concerns Vellum or Laser may be a more economical option and it will work, just not as well as Ink Jet.
You can make vellum and laser film blacker/ more opaque by using an artist’s darkening lacquer coating such as our Crystal Kote product but this adds a step to the process and requires drying time and can be a bit of a messy process that needs mastering.
Regardless of using ink jet or laser you should go into your printer settings and make sure the print quality is set at its darkest setting.
- The blacker the artwork the better the developed resists will be in both sharpness and strength.
- Vellum and Laser film prints do not get as black as ink jet and so some light gets through during exposure resulting in longer washout times and less fine detail quality.
- Vellum and laser prints can be darkened by using a darkening lacquer such as Crystal Kote.
- Ink Jet is the recommended print process because it gives near total opaque print and this results in the best quality developed resists.
- All printers should be set at the best quality print in the printer setting.