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If you are new to the industry or a veteran of 20+ years, you have heard of 4 color process printing. This style of printing is one of the many ways to achieve photo realistic prints. With only 4 colors, just about any image can be recreated on a garment. Hard to believe? Maybe not. Even though it sounds over simplified, it was discovered that you can break a photograph down to 4 primary colors – cyan, magenta, yellow and black. By breaking the photograph down to 4 primary colors we can then print using halftones and white to create the photorealistic image we want. Here are a few things you should know before diving into process printing.
White is the ideal shirt color for CMYK printing because CMYK inks are translucent. However, you are not limited to only printing on white garments. If you are printing on a darker shirt, use a white under base to really make those colors pop.
The garment that you use to print on should have a tight weave so the individual “dots” of your design have a surface to print on. While the weave should be tight, don’t use heavy thick materials as these usually interfere with the detail of the halftones. Not saying that it can’t be done – it just isn’t recommended.
This one is simple - the higher the quality of the image the better the print.
Printability is another factor to consider. Colors that look great on the computer screen may not work when they get printed on the fabric. Likewise, doing a test print on paper doesn’t mean it will be the same when it is printed on fabric. For best results use test pellons (available in black and white) or a fabric that is a similar color to your actual print job.
Color separations start with a print ready file which is something you can achieve using programs like Photoshop. Alternatively, you can use a separation software meant for screen printing. You want to make sure that the file you download is a high resolution JPG. The very first thing you should do when you open your program is make sure it is set to CMYK. When using programs like Photoshop, the default settings are ideal for printing on paper – not shirts.
Not only will you strip the image down to the four main process colors, you will also need halftone dots. The dot shape will have to be adjusted to and elliptical shape which works well with the squares created in the screen mesh. It is also important that you adjust screen angles for each color.
One of the unique aspects of process printing is having the ability to integrate texture, gradients and special effects within your design.
For CMYK printing you want to use a high mesh count. 305 or higher is industry recommended.
While people have their preferences a general rule is to print light to dark. The preferred print order for CMYK printing is yellow, magenta, cyan and black. If you are printing with a white under base, you will have to print that first.
Wet on Wet
Time to print! Generally there is no need to flash between colors unless you are printing a white under base. In that case, only the under base is flash cured. The inks blending create a myriad of tones so it is important that you print wet on wet. One of the biggest challenges of CMYK printing is to lay down the same amount of ink to create a consistent image. If you are manual printing, make sure to use only one print stroke per color. The ink must not retouch the stencil once the print has been made – you will have a mess otherwise.