One of the first things I advise people to do when working with screen printing and direct liquid emulsions is to use 100% opaque film. This is something that we have become accustom to not having. In the early days of screen printing the film positives were made using a genuine photographic process producing a silver nitrate piece of film that was just absolutely opaque. The density of the image area in the film was 100%. The film was made with “process” cameras or “stat” cameras and processed through small automatic developing machines. As the computer came of age we started to see cheaper and easier methods of producing film positives emerge on the commercial market. The draw back or compensation for the lesser cost is: many computer produced laser vellum products and inkjet or laser films are inferior compared to their true film predecessors. Check out the article called “Outputting Artwork To Film” on the Catspit website.
Another important thing to understand is the different types of emulsions available for making your screen. The basic three types of direct emulsions are Diazo, Photopolymer, and Dual Cure. And note that it is UV light that emulsions are most sensitive to. That is important when choosing your light source for making your screens. Your exposure unit, film quality and emulsion will determine your exposure time; therefore having an exposure source that has a good UV output will be beneficial. The three different types of emulsions will have different exposure latitudes and benefits with different light sources. Take a look at the article called “Understanding Emulsion" and "Trouble Shooting Tips For Direct Emulsions".
Sometimes for beginners it can be difficult to understand which product to use for which application. In screen printing we use on a daily basis what are known as consumables. These include but are not limited to inks, emulsions, and chemicals. Here is a helpful article that is in a chart format to make it easy to identify the information you are looking for regarding consumables. It is a quick reference and you should always thoroughly research your products. Browse this chart to get a quick look at consumables, “Consumables Usage Charts; Inks, Emulsions And Chemicals”.
A very important tip I like to give to beginning screen printers is about mesh tension. Using a tightly stretched screen has benefits beyond print resolution. You can achieve better coverage in certain applications with the correct mesh count. Or you can conserve ink by using tightly stretched screens with higher mesh counts to print lighter colored shirts and get great coverage there too. Learn a little more about proper mesh tension by reading the article called “Proper Mesh Tension: Getting Better Stencil Performance” on the Catspit website.
On a last note, artwork is the single most important step to creating an excellent, high quality print. If your artwork is not set up properly for screen printing, not only will the print look bad but the job could be very difficult to print. It is important to educate yourself on how screen printing renderers graphics and understand how to set up your art to easily print what you want. Take the most time working on your art and be sure of it before you even think about going to screen. If you are unsure of how to do the art, seek out a graphic artist who has experience with screen printing. This will save you much materials and headache.
By better understanding the way screen printing is technically applied to achieve optimum results is an asset to your printing success. Learn the principles and techniques of commercial screenprinting and adapt them to your home application. Whether or not you intend on printing tee shirts for fun or for profit, learning the technical details of the process will facilitate your efforts. In the end, this methodology will give you better print results with less effort.