Key Points for 4 Color Process Screen Printing
Posted by Mary Yaeger - 8/7/2017
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.
Shirt Color
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.
Art Quality
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
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.
Mesh Size
For CMYK
printing you want to use a high mesh count. 305 or higher is industry
recommended.
Print Order
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.
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