Substrate Options for Printing Signs
I wrote a PIE Blog article a while ago about options for printing large format images on inkjet equipment. Many of the options I suggested were signs of various kinds, ranging from exterior banners printed with solvent inks on vinyl sheets to table throws printed on fabric to actual flags. Inkjet printing is very flexible. In fact, you can even print on rigid substrates, depending on whether you have a flatbed option for your inkjet printer. (For instance, you might want to print directly on wood doors.)
But in many cases your needs will be more modest. Perhaps you will need to print 100 real estate signs, or maybe you will need ten podium signs for speakers at your next convention.
What are your options?
With this question in mind I did some research online and found a good article by Mark Krenn (Coastal Creative, 7/15/17) entitled "Sign Materials 101." Here is the gist of the article along with my own experience as both an art director/production manager and a custom printing broker. (I would encourage you to Google the article online.)
The first question to ask if you need "rigid" signage (as opposed to flexible signage that you might print on vinyl scrim or fabric) is where you will display the sign: inside or outside. The next question to ask is how long you will need the sign to be "pristine." (That is, how long would you like it to present your brand in the best possible light by looking new?)
Indoor signage for the most part comprises three options built around a foam inner core. The core makes the sign light and easy to transport, while the coating on the back and front of the sheet gives it various levels of durability. Here are the options:
1. Foam Board--The interior is polystyrene foam. The exterior is matte paper. This is what I used to use as an art director for podium signs. I would print out the art on paper and then spray mount the sheet and roll it down with a "brayer" to attach it firmly to the foam board. Then I would trim away any excess and cut the sign to its final size with a ruler and X-ACTO knife. The sign was not durable, but it was the least expensive option. Since the signs were single-use items and often lost in transit, this was not a problem.
2. Ultra Board—This product has a foam core, like foam board, but instead of paper, the exterior front and back sheets are glossy polystyrene. The sign is still very light. It is more expensive than foam board, but it will last longer. It will also flex a little, whereas foam board will snap in two with a little pressure, and you can inadvertently damage it with your fingernail. In addition, dropping foam board will easily dent the edges. In contrast, Ultra Board is stronger but a little pricier.
3. Gator Board—Gator Board is one step up from Ultra Board. Like foam board and Ultra Board, Gator Board has a polystyrene foam core, but instead of matte paper or gloss plastic sheets on the front and back surface, Gator Board is covered in wood veneer. This makes it rigid (Ultra Board will flex a bit; Gator Board will not). This also makes the printed product a lot sturdier and long-lasting for interior signage.
Foam board, Ultra Board, and Gator Board are for indoor use only. Outside, the paper covering the foam board will degrade, and the wood of the Gator Board will do the same. In all three cases, the foam interior of the board will also degrade quickly in the sun, rain, and wind. So keep all of these products inside.
How do you choose one option from three? Consider price, surface, durability, and the length of time you plan to use the product.
If, for example, you want a permanent free-standing indoor sign for a display (or even a sign hanging from the ceiling), you might choose Gator Board. It's very upscale, with its wood veneer surface.
If you are making podium signs—as I did—and you want them to last longer than the foam board signs I made, you might pay a little extra for Ultra Board. This would be good for multi-use indoor signage, when you want the surfaces and edges to stay pristine and you know the signs will be treated carefully.
Once you know your sign must tolerate wind, rain, and the damaging ultraviolet rays of the sun, your cost goes up, and your options shift to Sintra, Coroplast, and Dibond metal signage. Here's the difference:
1. Coroplast—Think about the cardboard used for cartons. The walls of cardboard cartons comprise an inner and outer sheet made of paper, and sandwiched between these two there is a fluted interior. The ridges go back and forth like a continuous "S". This makes the box both strong and lightweight. (The box doesn't collapse from the weight of its contents while adding only minimal weight to the overall cartoned product.) It's ingenious, really. Coroplast is the plastic version of corrugated cardboard. You may have seen yard signs for political candidates made from this material. The open fluting at the edges allows you to easily insert thin wire supports to stick in the ground and hold up the signs. Coroplast signs will tolerate the rain and sun without degrading much (although they don't hold up as well as the next option, Sintra). Perhaps this durability is why you will also find Coroplast in the US Post Office (it is the material used to make the boxes for sorted letters).
2. Sintra Board--This is one step up from Coroplast. It is a solid sheet of PVC plastic. For the most part, it will withstand anything (granted, the printing itself may not). That said, it does have an off-white color (unlike Coroplast, which is whiter and brighter, and this will affect whatever is printed on it). It also has more of a grainy surface—like sand—than Coroplast, although Coroplast does have fluting, which may add a visible "waviness" to the printed surface of a sign. (This is particularly true since Coroplast is somewhat transparent, and you can see the fluting through the exterior sheets). (Think of printed cartons made with corrugated paper. You can usually see an uneven waviness in the printed press sheets laminated to this substrate.)
3. Dibond—If you need a permanent outdoor sign with type or stenciled artwork, Dibond is the best choice. This material has a front and back aluminum composite material bonded over a polyethyline core. It is rigid, attractive, and permanent. (In contrast, for instance, if you were to cut out letters or art from a Coroplast sign, the substrate would fall apart. It is flimsy compared to Dibond. But Dibond will still be rigid even when type and images have been cut out of the surface. That said, Dibond is also the most expensive option.
How to choose?
If you're printing 100 political signs that will only need to last for a few weeks, I'd choose Coroplast. It's less expensive and good enough for the task.
For a long-lasting exterior sign, if you don't mind the textured surface and off-white color, I think Sintra would be your best bet. Few things last longer than a solid, thick sheet of rigid plastic.
For something upscale that you want to be permanent, particularly if you want to die cut letters and art, choose Dibond. Dibond also has a few other benefits. It's metallic, so it looks classy. The solid polyethyline core (and aluminum composite construction, in contrast to pure aluminum) make it lighter than a similar, solid sheet of aluminum. And based on the images and products I've seen, the polyethyline core can be of a contrasting color. So anything you cut out of the front sheet of aluminum will have a contrasting background immediately behind it.
Options for Printing
Your two best options for printing the actual artwork of these signs on the materials I have suggested are as follows:
1. Inkjet printing
2. Screen printing
You can also hand paint signage on these substrates.
(You basically need to avoid high-pressure printing technologies such as offset lithography. With Coroplast, for instance, offset press rollers would crush the fluting between the plastic outer sheets, just as the rollers would crush paper-based corrugated cardboard.)
Talk with your printer about which inks to use. This will be based on whether they are for indoor or outdoor use. (For instance, for outdoor signage, solvent inks will take severe weather better than some other inks.)
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]