Screen Printing - New Fun With Old Trees

CMYK Halftone Magic- A majority of screen print work is printed using inks mixed for a specific color.  Qualities such as color and transparency are controlled on a per-batch method. The color in the bucket is what will print on the page. This is "spot color"  Another prevalent color methodology is CMYK process color.  CMYK is printed using Cyan, Magenta, Yellow and Black. (Black is noted as "Key" in CMYK.) The combination of these four colors along with the variable dot size of halftone, can replicate a wide color gamut. Interestingly, if only solid color inks are overprinted CMYK only yields seven colors.  It's the halftone that provides the color range. Rather than being mixed in the bucket, the colors are mixed in your eye!  From color laser printer pages to vehicle wraps, CMYK halftone printing is everywhere! Printmakers can lever CMYK technologies to get full color prints with minimum stock of ink colors.  Nothing comes for free thoug...

Screen Prep for Printing- OK.  You have your art, screens and ideas prepared.  It's time to print! When performing a print run, the screen needs to be prepared.  Usually this is simply taping off the screen edges and making sure there aren't any open screen areas that aren't supposed to print.  Something such as a screen label or note that was burned in to the emulsion to organize your screens really isn't needed at the printing stage so tape these items off.  Before mounting the screen into the fixture, use clear packing tape to effectively block out non-printing areas from the final print.  Clear packing tape works better than masking tape for screen masking because it isn't so sticky that it damages the emulsion when it's removed. Emulsion is tough, but not indestructible, stuff. Cleaning the screens between use with water (assuming water based ink) also loosens the adhesive of the packing tape so it comes off when it's supposed to -but not...

Media Location & Registration for Printing- In order to print multiple colors precisely, some method of accurately placing media must be employed.  Two techniques outlined here are taped corner registration and pin registration.  With some work there is no need for super accurate registration.  For example, with the Drawing ink and Filler example the registration used was very loose so taped corners did quite well.  With a process color (CMYK) print registration is imperative. Since colors are "mixed" in the eye, a small bit of misalignment between screens / colors causes large changes in the final look. Taped Corners- Taped corner registration is quick and cheap.  It consists of, you guessed it, tape markers on diagonal corners of the print media. Using this system does take a little extra attention in placing each new sheet of paper but beyond that, it's an effective method.  With the work surface prepare...

Positives -Film, Laser or Otherwise With the Rubylith technique a master image was cut from material that allowed us to control what parts of the emulsion were exposed and washed out versus what areas were to remain.  Rubylith offers fast exposure times at only ninety seconds in the exposure machine. But it is also labor intensive to create the masters.  Frequently, as part of the creative process, images are first made on a computer that are then used as a tracing guide.  This works well if a handcrafted quality is desired. Often though, the computer image will be exactly what is wanted.  By using layers in a graphic program, a master image can be created for each screen.  To get the best result, three things are required.. First, that the image be printed on a laser printer- ink jet printers don't print opaque enough images for this technique although they work well when printing to transparent film. Second, that the graphics program can make use o...

Rubylith is a little different than what has been discussed to date.  It resembles the hand cut stencil in that it is a hand cut process but unlike the hand cut stencil the final step is to shine high-intensity light through the Rubylith to a photosensitive emulsion.  The Rubylith prevents the emulsion from chemically setting. This is another "positive" process.  Where the Rubylith has masked the emulsion is where the ink will go on the print. Rubylith is not sensitive to light and is made of a two layer plastic film.  The top layer is red and the carrier is clear to light pink.  The objective with Rubylith is to use an x-acto knife to cut the artwork out of the red layer while leaving the carrier layer underneath undamaged.  Small cut-throughs are not a problem but if you've made ribbons out of it, lighten up on the blade or move back to a regular stencil. Cutting takes a bit of practice, my first Rubylith cut almost fell apart!  Rubylith can h...

For the second technique we'll consider Drawing Fluid.  The technique is fast, easy and is best suited for images that need to have a hand-painted feel.  The set up is easy.  Using a clear screen, simply apply the drawing fluid directly on the screen. Make sure the back of the screen is not touching anything.  If the back of the screen touches another object, the drawing fluid will give an unpredictable image as it flows along the places of contact.  A good trick is to tape cardboard spacers to the back of the screen frame. Doing this will hold the screen up and off the work surface.  Use Drawing Fluid just like you would ink or paint.  Drawing fluid is a positive process. Where the drawing fluid is applied will be where the ink will go on your print.  The image does not have to be completed in one session so take your time! Different ways to use Drawing Fluid. If you are more comfortable tracing ...

Screen printing is far and away more than t-shirts- and it can be a lot less complex.  The Cut Stencil technique is very easy to do and amazingly capable for the beginning screen printer.  At it's heart, the screen in a print process is a way to meter ink and allow the ink to be placed on an object in a controlled fashion.  The printable image is commonly adhered to the screen, but it doesn't need to be.  The stencil project consists of an image cut out of an acetate sheet and simply taped to the back of the screen.  Clear acetate or plastic sheets used for transparencies work great here!  The sheet needs to be about the grade of an x-ray image, slightly stiff but not so thick that it can't be cut accurately with a sharp x-acto knife.  Plastic is required so the stencil is ink and water proof.  the reasoning behind this is so the stencil will not degrade during a print run or subsequnt clean up. In this example, the floral se...