Impressions - August 2013 - (Page 58)

talking SHOP Screen Printing Technique Controlling Variables, Part 1 In this three-part series examining advanced screen printing techniques and best practices, we will look at factors related to prepress procedures. By Rick Davis, Contributing Writer a lthough the discipline is well over 1,900 years old, there still is no absolute or speciﬁc set of rules or guidelines to determine the best methods required to guide newcomers through the textile screen printing process. One mistake many industry newcomers make is failing to identify and establish the procedures needed to control the variables that can and do occur within the process. In this installment, we will review the primary variables that require controlling or standardization in order to maximize the desired quality results to maintain your primary client base. ARTWORK ENGINEERING It’s important to remember that there is more than one way to do something. I visit far too many facilities where procedures are established and followed for one simple reason: “That’s the way it’s always been done.” Such situations mandate thinking outside the box. In relation to engineering the artwork for your screen printing job, you should consider the options that are available to make it easier to produce, while maintaining the design’s integrity. A majority of the designs on dark garments are printed with an underbase white and hit a second time with a highlight white to ensure the opacity of the white ink. In 90% of graphics printed onto a dark ground, this is the correct thing to do. However, for the remaining 10%, and when thinking outside of the box, you should consider the colors within the graphic that could be used as an underbase as opposed to always using white ink. One of the best colors to use for an 58 Impressions | August 2013 alternative underbase is gray. Typically, this color is a percentage of black and has the following advantages: 1. It is extremely opaque. 2. The additional opacity allows for use of ﬁner mesh counts and thinner ink ﬁlm as a underbase. 3. The thinner ink ﬁlm and darker shade allow for faster ﬂash times than when printing with white ink. The only disadvantage is that you now need to use high-opacity colors to properly cover the darker shade of the underbase. This is not a problem for most screen printers, as we all use high-opacity inks on a daily basis anyway. Another thought to consider when overprinting on an underbase is that when you can remove a screen from the weton-wet sequence of the post-ﬂashed color, the printing process will become easier. The primary thought here is to use a color from the graphic, when possible, as the underbase instead of adding to the process with multiple white inks. When white ink is required, you still can print it last through a 156 mesh onto the underbase. In the same vein with the thought of minimizing the number of screens following the initial — or in this case, the last — ﬂash in your sequence, one trick I have been fond of using on multicolored graphics is printing the black portion ﬁrst in the sequence, followed by the underbase on darker or medium-shaded garments. As many graphics are separated as “butt-ﬁt” registered colors anyway, there is little reason to run the black later in the sequence. Butt registering refers to the way ink colors meet without overlapping or having any space between them. This also is referred to as butt ﬁtting and “kiss registering.” In this scenario, artwork permitting, you can run the black prior to the underbase and be done with it. Here again, removing any color from the back end of the sequence only simpliﬁes the printing process. PREREGISTRATION BASICS I have seen preregistration systems incorporated into most shops with more than one automatic screen printing press. Most automatic press manufacturers today have preregistration for their respective systems. Although they may vary in design, the goal is the same: to ensure your screens are photographed and registered into the press in as tight of a registration as possible. This minimizes the time required to register each ﬁlm onto the screen and each screen into the press by hand. There are two primary preregistration systems available today. The ﬁrst and most widely used is the pin/punch registration. Different variations of this system exist, although they all achieve the same goal — minimizing setup time. The second type of preregistration system is the computer-to-screen (CTS) system, where the screen in preregistered prior to being imaged in a CTS imaging system. This type of system also is called a direct-to-screen (DTS) system. In the ﬁlm system, pre-punched carrier sheets are used to allow you to align each ﬁlm positive onto the carrier sheet while being aligned with a registration board. The initial carrier sheet is aligned onto the registration pins, which are attached to the registration board. impressionsmag.com http://www.impressionsmag.com

Table of Contents for the Digital Edition of Impressions - August 2013

Impressions - August 2013
Contents
First Impressions
From the Show Director
FYI
Product Gallery
ISS Conferences
Digital Printing Opens New Doors
Feel-Good Fleece
10 Reasons Start-Up Decorators Fail
Shop Spotlight
Shop Spotlight
Embroidery Technique
Embroidery Production
Screen Printing Production
Screen Printing Technique
Online Directory
Classifieds
Ad Index

Impressions - August 2013