Although paperboard and corrugated board often ship to you flat, they act quite differently when they are cut, creased, folded, printed, and then put to work in a load. Paperboard is a generally denser material used for folding cartons, sleeves, and smaller retail packages. Corrugated board has a fluted layer between liners, which makes it thicker and more protective. It is wise to consider both your product and the way the container will be converted when determining which of the two you would like to use, rather than choosing based on the strength of a sample.
A new convert might focus on the surface and lose sight of the fact that the two substrates perform quite differently. Paperboard can be smoother for print quality, may make sharper creases, and produce a tighter, more compact package. But paperboard can sometimes be too thin for the application; it may bend too much, or even crack and tear around a product. Corrugated board, on the other hand, will generally resist crushing and provide more protection when stacked or dropped. Corrugated board is also thicker than paperboard, so a dieline developed for paperboard cannot be transferred directly to corrugated board because of differences in thickness that affect panel size, closure tabs, laps, and product fit.
Stiffness is one property to look at, but it is not the same thing as thickness. If you find two substrates that have about the same caliper, you will not necessarily have two materials that will bend equally. This may be because of their raw materials, their coatings, the type of paper that is used for their face and back liners (in the case of corrugated), or their flute construction. Paperboard also has a grain that can impact how well it can be scored and folded. If a crease or fold is made perpendicular to the grain, there could be some resistance in folding, or even cracking on the surface. When working with corrugated board, the flute provides another directional characteristic. Flute direction impacts how well the board will bend, how heavy a load it can support, and how it will respond to pressure on the edge.
To illustrate this process, let’s take a smaller-sized package and build two blank packages with approximately the same overall dimensions, one in paperboard and one in corrugated. If it is possible, try to use the same panel arrangement for each package to provide a fair comparison of how each material converts. Then compare the ease of cutting, the way in which each score is cut, how clean each fold is, where each lap and closure will occur, and how well the product will fit. Gently squeeze the sides of both panels and apply light pressure to the top, and repeatedly open and close each sample to compare how they respond. You might find that one material is not better than the other, but rather that some of its characteristics are a help rather than an impediment.
It is wise to also keep an eye out for how each package will print and be finished. Some materials are better suited to printing fine print, process colors, or fine graphic details than others. For example, a coated faceliner on one grade of corrugated might look very different when printed than an uncoated face sheet on another grade. Lamination, varnish, foil, and coatings, which are often treated as nothing more than decoration, will also affect how a blank will look, how it folds, and how it can be recycled. A heavy coating near a crease or fold can crack, and a large ink build-up can accentuate cracks and tears around a fold.
While looking over the finished samples, try to look past the front of the box to notice corners that may be crushed or broken, edges that may be damaged, creases that may have cracked or opened, flutes exposed, laps or closures that may be weak, panels that may not lie completely flat, or products that no longer fit well enough. The material that is suitable for this task is the one that you can convert, assemble, close, handle, and inspect in the most successful manner. Next time you get two samples to consider, bend an unused strip or two in each, fold each blank on a score line, or press down with your fingers on the corner. While these tests are minor, they may provide far more information than what is seen on the surface of the printed blank.