UV Printing CMYK + White Ink = Saturate Colors

You may wonder why I am singing praises about printing in white ink on a UV Direct to Substrate Printer?!  Hasn’t white ink always been a part of the digital world?  Well, not exactly. What we have been accustomed to is having a white base substrate on which to print on.

Enter the world of flatbed printing services, also known as direct-to-substrate printing.  Most of the instant cured inks made for the UV flatbed process have always come in the standard palette of CMYK (cyan, magenta, yellow, black). With the newest UV flatbed printers, the doors have been blown open, allowing you to print on any flat panel substrate not only in CMYK, but also in white ink!  Printing surfaces can be wood, metal, glass, acrylic, and whatever your imagination can allow. When printing on any surface, you want the finished piece to be bold and beautiful.

In order to switch over to flatbed printing, the lure of different substrate backgrounds is not enough. The high standard  quality of large format graphics must print must be just as good when printed on wood, right? Otherwise, it would be reserved for novelty printing along. You still want sharp images and saturate color, right?!

What would happen if you were to put light colors onto something other than white, such as wood or aluminum?  Wouldn’t your gray scale range of tones be drastically reduced since your base is a mid-tone? My guess is that the colors would be muted and murky, and be of low contrast. What if could acquire a full range of tones while still printing on your choose of a base substrate? What if you could selectively allow transparency on certain parts of your graphic and have a mix of opaque printing over white in some areas, and transparency over others? With UV flatbed digital printing, this is possible!

The most recent generation of UV printers are now equipped with white UV ink capability. All former generations of printers did not, so you must check with your printer to see if she has white ink capability. This capability translates in graphics such that window cling graphics on clear vinyl can either look transparent, like stained-glass windows or they can be printed as opaque prints. You get to choose the look you desire.

For backlit signs in lightboxes, you can acquire the new “day/night print.” This means you will be getting a print that has been reverse printed on the plex, allowing it to hold its density and color saturation. Day-night prints view well as either a reflective print or a backlit print. In the old days, an unlit ‘duratrans’ looked dark  and did not read well when not lit.

Not all white ink printers are alike.  There are varying shades of white (like paint) and varying degrees of opacity.  When looking to print on dark surfaces, you will want to inquire about their whites; and perhaps even have a test print run.  You might even inquire if the white UV ink has titanium dioxide (TiO2) suspended in it.  Everyone knows what its like to paint a room white once its been painted dark forest green, right?! You usually need a primer base or several coats; in this instance, it refers to the number of ‘passes.’ Worth noting is now you can  print white graphics on dark substrates, which was formerly not possible.

So, as a review of printing in white ink:

• On a dark substrate, you can use white ink as an undercoat on a non-white surface.
• You can overprint it on see-through substrate to achieve full color saturation.
• You can use white as the diffusion layer while reverse printing the back side to achieve a day/night backlit print.
• You can use it as a spot color or even do a combination of some of the above.

And one more tip about UV direct to substrate flatbed printing services: When choosing one, look for a wide or large format print provider that only has a “true, dedicated flatbed printer.”  This means the equipment should have a stationary (vacuum board) bed with a moving head or “gantry.”  The gantry is the X/Y carriage that moves across the substrate (as opposed to using a printer with a moving bed and stationary head).  Having precision registration is key to getting the tack sharp results you expect! If the print registration is not accurate, then it is difficult to to overlay multiple passes of ink on fine detail such as fine text. The base coat of white can show on the edges and give a soft or sloppy appearance. With a true flatbed UV printer, the substrate is held stationary with vacuum, and the registration between the ink layers is accurate.    

Sharp image + sharp color =  happy customers

For more information on white ink printing with true flatbed printers, call 1.800.829.4562