Large format printing is big now, not just in terms of size but also in terms of popularity. Just look at the sides of buildings, buses, and cars, decked with large format print work. Ink jet printing has revolutionized advertising in the last decade. Therefore, it behooves us to understand some of the options for finishing, within the arena of large format printing, as well as understanding how the ink is sprayed onto the paper or plastic substrate.
Mounting Large Format Prints
In many cases, the product that comes off the inkjet press is relatively thin paper or plastic. (This is true for roll-fed inkjet presses at least. Flatbed presses can print directly on much thicker substrates.) Therefore, in many cases you will want to mount the print on a rigid base, such as Gator Board, Fome-Cor, Coroplast, Sintra, or even metal.
Gator Board and Fome-Cor are similar in that they both have a lightweight foam center covered on either side by paper or plastic. This makes them very light (as well as rigid), but they can be easily dented or crushed (Fome-Cor more so than Gator Board). Gator Board is also more durable than Fome-Cor since the front and back sheets of Gator Board are made of paper, plastic, and adhesives, while the front and back sheets of Fome-Cor are paper.
Sintra is a solid PVC plastic board. It is very strong. However, it is also a little heavy for its size.
In contrast, Coroplast is very light. Imagine a plastic version of corrugated cardboard, with fluting inside covered with a top and bottom sheet of thin plastic (strong, light, and easy to cut). You may have seen this material used for political signs or real estate signs on people’s front lawns, or signage on the back of buses.
You can mount your large format printing posters directly on these materials, using anything from spray adhesive to dry mounting film (using a machine that applies heat and pressure to activate an adhesive tissue sheet). Or, if you have a flatbed press, you can print the large format graphic directly on the rigid board. (Or you can even screen print the graphic directly on the rigid board.) The benefit of the above-mentioned mounting materials is that the art stays flat and does not curl.
Laminating and Coating Large Format Prints
Another way to present (and preserve) your large format print is to cover it with a film of clear plastic. This is known as lamination. Lamination protects the print from the elements (sun, moisture, dirt), gives it a bit of a sheen, makes the colors more vivid in some cases, and, along with the mounting board, keeps the large format print flat.
As an alternative, you can add an aqueous coating (water based) or UV coating (cured, or hardened, by exposure to ultraviolet light) over the print in much the same way as you would cover the large format print with a laminate. This will also protect the underlying large format piece, but unlike a laminate you can choose to cover either the entire print (flood coating) or only certain portions of the print (spot coating).
Cutting Large Format Prints
Sometimes you will want your final printed piece to not be square or rectangular. In these cases, you will need to cut the mounted piece into an irregular shape. For this task, your options include metal dies, lasers, routers, and knife-based plotters.
Like cookie cutters, the sharp edges of a custom fabricated die will cut away anything that’s not a part of your design (for example, they will cut out the silhouette of a stand-up figure, if that’s the end-use of your large format piece). Using a letterpress, cylinder press, or other equipment, the commercial printing supplier will press the custom-made metal die into the paper of the large format print to cut away the excess printing stock.
Lasers and plotter-based knives will also cut irregular shapes, but unlike metal dies, lasers and knife-based plotters use digital information stored in a computer file to position the cutting elements. Therefore, they are much faster than physical dies. In addition, you do not have the added expense of creating the metal die. Also, you can produce much more intricate die cutting work with a plotter-based knife or a laser than with a metal die, and, by using variable data, you can even alter the die cutting for every piece that comes off the inkjet press (which you can’t do with a traditional metal die).
Routing is more complex than laser, knife, or traditional die cutting. One would use routing equipment for more intricate cuts or grooves, perhaps to fabricate individual elements of a larger graphic structure, or signage with beveled letterforms cut out of wood.
This entry was posted
on Monday, August 13th, 2012 at 6:03 pm and is filed under Digital Printing, Large-Format Printing, Poster Printing.
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