ACM/HPL/GRP or PC? A quick guide to different graphics panel materials

When it comes to crafting outdoor graphics, the choice of panel material is every bit as vital as the design itself. Looking ahead to 2025, factors such as robustness, environmental credentials, UV resilience, and resistance to vandalism are paramount – particularly as signage in public areas is expected to endure challenging environments, shifting weather patterns, and increased pedestrian flow.

With mounting pressure to adhere to environmental standards and curb long-term upkeep expenses, numerous organisations are gravitating towards materials that not only present well but also deliver sustained performance. Sustainability has now become a key consideration in material selection, with high-pressure laminates (HPL), encapsulated aluminium, and etched stainless steel distinguished by their longevity and reduced environmental footprint.

Having designed your sign, you have the problem of deciding what type of panel to put in it. There are loads of different sorts, all at different price points and with different properties. To help you we’ve summarised the common panel types below in roughly ascending price order.

UV resistance levels are guides only as formulations and print techniques are constantly evolving, but medium resistance is 5-7 years and high resistance is 10+ years. This also depends on the printed graphic, location, and orientation of the finished panel.

What are the types of graphics panel materials?

There’s a wide range of panel materials available for outdoor graphic design, each offering unique advantages in terms of durability, UV resistance, cost, and environmental impact. Below is a breakdown of the most commonly used options, helping you choose the right one for your specific project needs.

PVC foam board (MatteRok)

Sometimes called Foamex, this is a lightweight PVC foam board, usually 3mm or 5mm thick. It accepts digital print and screenprint. Often used for temporary signage as it is very economical and lightweight. Vandal resistance – low.  UV resistance – medium.

ACM aluminium composite material (BaseRok)

This board has a black plastic core with an aluminium face and back. It’s easily recognised by viewing it from the edge. Accepts digital print, screenprint and vinyl lettering and usually has a laminated finish for extra UV and graffiti resistance. Used extensively as very economical and stable. No scrap value. Vandal resistance – medium.  UV resistance – medium.

Aluminium (FlatRok)

This material is a solid aluminium sheet and is similar to ACM in finished appearance apart from having a silver edge. It has similar properties but is slightly more expensive. Accepts digital print, screenprint and vinyl lettering and usually has a laminated finish for extra UV and graffiti resistance. Used extensively as very economical and stable. Vandal resistance – medium.  UV resistance – medium.

Encapsulated aluminium board (HardRok)

This is a premium board at a moderate price point. The panel is powder-coated, then a print is applied and the panel is sprayed or powder-coated with a high-grade finish. Accepts digital print.  Vandal resistance – high. UV resistance – high.

Polycarbonate (ArmaRok)

This is a very tough panel, the print is laminated onto the reverse so is very well protected against impact and sunlight. However, polycarbonate can scratch so a matt finish is recommended. Vandal resistance – high. UV resistance – high.

Etched stainless steel plate (DeepRok)

Used for topographs and viewing panels. The steel plate is chemically etched and filled and works equally well in contemporary and traditional settings. Vandal resistance – high.  UV resistance – high.

Cast polyurethane resin (CastRok)

Used for heritage settings, these panels are individually moulded and painted. Very durable with almost a ‘cast-iron’ look to them. Vandal resistance – high.  UV resistance – high.

GRP Glass reinforced polyester (ToughRok)

A very durable material although not considered particularly environmentally friendly for disposal.  Used extensively at remote sites as very durable and weatherproof. Scratches or impact marks can be polished or sanded out. Vandal resistance – high.  UV resistance – high.

HPL High pressure laminate (EcoRok)

This is a paper sheet laminated between layers of kraft paper and then compressed in resin to create a chemically solid block. Very stiff so it doesn’t need a backing panel, allowance for shrinkage/expansion must be made in the fittings. 

Graphics quality is not so high for small reversed-out text due to the ‘wet’ process but can still produce very high-quality durable panels. Impervious to salt water. Vandal resistance – high.  UV resistance – high.

Which interpretation panel is right for you?

Selecting the most suitable panel for your outdoor graphic design work can feel like navigating a maze, given the sheer number of materials on offer. 

To simplify this process, we’ve put together a handy comparison table. It spotlights the crucial characteristics of each choice – everything from how well they stand up to sunlight and vandalism, to their environmental footprint and common applications.

In closing

Choosing the proper interpretation panel material is jolly important for any outdoor graphic design project that’s going to be a success. Getting it right means your signage stays looking spiffing, lasts a good long while, and does the job it’s meant to – be that braving the elements, shrugging off the odd bit of bother, or fitting in with your green credentials. With a whole host of options on offer, knowing your stuff can make a difference.

Need advice on choosing the best signage material? Contact Hornbeck today—we’re here to help!