ZOO-INK Screen Print

Custom printing services including strikeoffs, dyes, pigments, and film positives. STRIKEOFFS: Terms and Explanations Hand Screen textile printing is as much an art and craft as a science. There are many variables that are beyond our immediate control. To deliver printed fabric to your high standards we need to print a STRIKEOFF before running production. In the Textile Printing Industry a Strikeoff (abbreviated SKO) is defined as a small run of fabric printed with screens for the first time after the screens are made, or fabric which is printed in new colors or on new grounds with existing screens. The entire screen must be used, and there usually must be enough yardage to show at least 3 repeats. Strikeoffs serve a number of functions. 1. Testing the screen to see if the image has been burned in properly. Look for pinholes, blockages, and any other areas of deficiency. 2. Checking the repeat to find the most accurate measurement. 3. Testing the colors to see if there is any color shift between color dabs and production conditions. 4. Testing the ground under production conditions. You can see in particular the need to run Strikeoffs when new screens are made ("burned"). This is why ZOO-INK partially includes the cost of a Strikeoff in the screen fee. We want to encourage our clients to order a few yards so we all can examine the screens and their printing results to maintain excellent quality standards. The only reason for not ordering a Strikeoff is to save time. Sometimes this is understandable, but it carries some risks. Since the Strikeoff is the basis for our standards of production, we cannot guarantee quality standards without a Strikeoff first. When grounds are known, colors are not critical, and the design is straightforward, we can proceed to larger runs without a Strikeoff, but it is always at the customer's own risk. After the screen has been printed once, there is much less need to print a Strikeoff. It is most valuable to check color matching, as there is almost always a slight shift between the color test and production conditions. A single frame Strikeoff (no repeats) may be sufficient for color checking. If colors are not critical a Strikeoff may not be needed. Occasionally a new ground fabric will not behave predictably under production conditions. If we have never printed on a certain fabric before we would like to recommend a Strikeoff. Also, sometimes fabric that a mill supplies as a sample will not behave the same way as a production fabric it delivers. You may think "why not set up to print 60 yards, and then if things go wrong stop printing?" Two reasons why that is not a good idea. Firstly, in production alternate frames are printed. Errors in the repeat will not show up until all the fabric has been committed and the between frames are filled in. Also, if the fabric shrinks too much it may ruin the repeat. Shrinkage sometimes does not show up until 30 minutes after the fabric is printed. It is then too late to fix the problem. There may be large losses of fabric, at the customer's expense. Secondly, our prices are based partially on the maximum use of the print tables. To hold up the use of a 30 yard table to test 5 yards is not efficient, and would result in higher prices all around. It may seem that if we can print 60 yards at $3.00 per yard, we should be able to print 3 yards for $9.00. Unfortunately, it takes almost as much energy and labor to print 3 yards as it does 30 yards. Screens have to be pulled, fabric set, stops set, ink mixed, fabric has to dry, documentation written, screens cleaned, put away, invoices written, and on and on. Many of these tasks take the same time whether 1 yard is printed or 60 yards. The efficiencies of scale play an important role in handprinting small runs. PIGMENTS AND DYES: Terms and Explanations In order to design fabrics most effectively, and to understand the limitations of the screening process, it is very helpful to know a little about current printing ink technology. Dyes will yield the softest hand (the "hand" is the feel of the fabric) and maintain the fabric's luster. The color goes through a chemical reaction and actually becomes part of the fabric. The process is very expensive and has difficult color control, yet it is suitable for fine silk scarves and other special projects. Most of this type of printing is done in Europe or the Orient. Pigments are much more economical to use. Pigments are generally more lightfast, more colorfast, and give greater color control. Pigment technology has developed tremendously in the past 15 years. 85% of the textile printing in the US is pigment printing. There are many different kinds of pigment printing. You may be familiar with the rubbery images printed on T-Shirts, which is a PLASTISOL ink. It is a very "high solid" pigment that is cured using heat. It is versatile for printing t-shirts, but it is not suitable for yardage printing. ZOO-INK uses no plastisol. ZOO-INK uses all water based pigments (also known as "Inks"). We cure (to make washable) most of the colors with chemicals that are added to the ink before it is printed. There are three types of pigments in use. 1. Transparent 2. Opaque 3. Metallic Transparent Pigments These are "low solids" pigments; when the fabric is dry there is very little residue left in the fabric. They most closely simulate the look and feel of dye prints. They are very transparent, which means that a color printed on top of a colored ground will be affected by the color of the ground fabric. For example, a transparent yellow printed on a blue ground will appear green. This can be used to your advantage through the use of smart design. For another example, transparent red printed on a black fabric will appear... black. The transparent pigments have very limited use on dark grounds. Opaque Pigments These are "high solids" pigments; when the fabric is dry there is lots of residue left in the fabric. They cause the fabric to be stiffer than the transparent pigments. However, they can be used to print light colors on dark grounds. This quality will greatly expand the possibilities in the design of new products. Also, an opaque color printed on a light colored ground will appear to "float" over the ground fabric, for some very interesting effects. Opaque Pigments will soften when washed, and are not as harsh on the hand as a plastisol ink. The absorption of the ground fabric can greatly affect the look of the print and the color value/hue. Metallic Inks These are actually a subset of the opaques, being high solids and relatively opaque. To achieve a metallic look, it is necessary that the Metallic pigment remains in the fabric after printing. Today's technology has given us metallics which are not metal at all. They are often made up of plastics, mica, and natural oxides. This gives greater chemical stability and eliminates tarnishing problems. There are true metal powders and inks available for special projects. Combinations These three types of pigments can be mixed in any proportions to achieve desired effects. The hue (color) of metallics can be changed by mixing with transparent pigments. We also mix the transparents and opaques, often to achieve a semi-opaque look with a softer hand. Of course the proportions in the mixture is a delicate balance. FILM POSITIVES: Terms and Explanations All the screens at ZOO-INK are made using a photographic emulsion process. To transfer the design onto a screen we need a FILM POSITIVE. This is a piece of clear or frosted Acetate or Mylar, with the design appearing on it in opaque black or photographic opaque red. The final printed fabric can be no better than the Film Positive. Making a good Positive is a critical step in the process. The Film Positive may not be film; it can be hand painted with opaque ink, cut Rubylith, paper collage, and other materials. We use the word Film in a very general sense, but the word Positive is a requirement. The Black areas of the film are where the ink, of any color, will pass through the screen. The Film Positive may be on any substrate, acetate and Mylar being the most common. Acetate is inexpensive, but unstable. Mylar costs more, but will not buckle, expand, or shrink. Mylar must be used for multicolor and tight registration designs. Photographic films are always on Mylar. Drawing or painting on Acetate or Mylar can be a cost effective way of creating a Positive. The ink used MUST BE OPAQUE. Hold the positive up to a bright light to see if any light passes through the black areas. Gray areas will give unpredictable results. Line thickness and fineness of detail are limited by the fabric to be printed on, screen mesh used, inks used, and other minor factors. We will discuss the problems of your particular design when we see your artwork. Multicolor designs may require special treatment in how the colors touch each other. This is called trapping. Trapping for hand screen textile printing is different that for machine printing, or paper printing.