When it comes to screen printing, creating a film positive can be highly complex, confusing, and even at times frustrating beginners and home printers with perhaps not as much knowledge of the process as others. The basic principle of film positives is to basically block exposure sources of light from curing the images emulsion during the actual exposure. For this reason, film positives will always work best when they are fully transparent and opaque. If you're thinking of trying it for yourself, be aware that it can be pretty tricky to get right but to help you out here we'll be providing a step by step guide to hopefully make the process that little bit easier for you. So, without any further hesitation, let's begin.
Step 1 To begin with, open the software you're using, Photoshop for example, and adjust your paper size to match your film positive paper size. Film positive paper comes in either sheets or rolls. the bigger the film positives you use the bigger the designs you can print- I use an 24" wide HP Design Jet 111 Inkjet Printer- These are less than half the cost of an Epson printer more commonly sold to new screen printers.
Step 2 Up next, make sure you select the check box to print registration marks on your film positives so you can use them to align and register screens. The reason for these registration marks is to help line things up and register your screens neatly on your platen.
Step 3 Get it looking the way you want it to look, and when you're happy, go to the "file" button at the top left of the screen, click "print" and ensure your printer is set up correctly.
Step 4 Next, it's a good idea to see a preview of you print before sending it to your printer. This helps to make sure your paper settings are correct so you can print your film positives correct.
Step 5 Click 'print' and your image will then be printed. Just make sure you have the right film positives in your printer, which we'll be looking at next.
Types of film positives to use Without the proper film positives, printing entirely black laser film or inkjet positives at home can be incredibly difficult. There are numerous types of film positives you can use, and they can actually vary greatly from one to the next. Here's a look at an example of a low quality, a medium quality, and a high quality film positive. Inkjet Films These films are made from clear plastic bases, with some being waterproof, whilst others are not. Most of these films work best with inks that are dye based, rather than some pigment based ones. To make film positives with Inkjet films, RIP software is not necessary. We print film positives with our HP Design jet 111 just fine. We use Ultra Seps Separation Software to convert our designs to halftones when needed. We do not use RIP software. Laser Films As density in these types of film are less easy to control, laser films are not as popular as inkjet films. The toner is often affected by the age of the cartridge and can only be controlled so much by the printer settings. The heat of the fuser often leads to larger images becoming distorted.