UV printing on wood: using the grain or covering it
are explained briefly when you hover over or tap them.
Wood is one of the most rewarding materials for UV printing. The ink usually adheres without a primer, and the grain gives every piece its own character. The most important decision is therefore a design one: should the wood show through the motif or not?
Which woods are suitable?
Light, fine-pored woods with an even surface are the easiest.
| Wood | Suitability | Note |
|---|---|---|
| maple, birch, linden | very good | light, fine grain, colours stay clear |
| beech | good | slightly reddish base tone |
| pine, spruce | medium | growth rings of very different brightness, resin possible |
| oak, walnut | medium | open pores, dark, white usually needed |
| bamboo | good | smooth, medium colour |
| plywood (birch, poplar) | good | cheap, the face veneer decides |
| MDF | good | very smooth, no grain, edges absorb |
Plywood is popular for signs, coasters and key rings because it is cheap and dimensionally stable. Pay attention to the quality of the face veneer. Knots, patches and glue residue stand out more after printing.
MDF has no grain and an even surface. Raw MDF is brownish, so you need white for clear colours. There is also pre-coated or white-foiled MDF, which can be printed like a white board.
With white or without?
UV ink is translucent. On wood this means: the grain shows through light and medium tones.
Without white the print looks natural and warm, almost as if stained. This suits rustic signs, logos in dark brown or black and photos with a vintage look. Light colours such as yellow and light blue, however, turn pale or greenish on wood.
With white you get clear, opaque colours. The grain disappears under the motif. This is necessary for company logos in exact colours, photos with skin tones and dark woods.
Often the nicest: white only under individual elements. The background stays wood, the logo glows. You control this via the white layer in the file, see Colour layers.
Expect extra effort. On wood, white often needs more than one pass for full opacity. That costs ink and time.
Preparing the surface
- Sanding: Sand rough surfaces along the grain, finishing with about grit 220. The ink traces every unevenness.
- Dusting: Remove sanding dust thoroughly, with compressed air, a tack cloth or a slightly damp cloth.
- Degreasing: If necessary, wipe lightly with isopropyl alcohol and let it dry.
- Lay it flat: The board must lie flat. Warped boards have a different distance to the print head depending on the spot, which leads to blurred areas. More on this in Blurred and overspray.
Untreated wood usually needs no primer. Varnished, oiled or waxed wood is different: oil and wax prevent adhesion, and varnish can work well or badly depending on the type. Only a test helps here.
Moisture and resin
Moisture: Wood should be dry and well seasoned. Damp wood keeps moving after printing, warps and can cause cracks in the ink. Store blanks for a few days in the room where you print.
Resin: Resinous woods such as pine have sticky spots at knots and in the growth rings. Ink adheres less well there. The best way to avoid resin pockets and knots is when choosing the wood.
Open pores: With oak and other coarse-pored woods the ink can run into the pores. In detail this looks uneven. Put fine lettering and lines on fine-pored wood instead.
Varnish and protection
A layer of varnish protects the print from abrasion and makes it easier to clean. For coasters and decorative cutting boards this makes sense. A glossy varnish makes colours on wood look richer, a matt varnish looks more natural.
Important: do not use printed surfaces as a cutting surface or for direct food contact. UV ink is not intended for that.
Outdoor use
Wood outdoors is a double challenge. The wood itself moves with every change in weather, swelling and shrinking. The ink only follows this to a limited extent. In addition, wood turns grey in sunlight.
For outdoor signs it helps to use:
- dimensionally stable material such as waterproof-glued plywood
- sealing all sides, including the back and edges
- a protective layer over the print that is suitable for outdoors
- realistic expectations: a few years rather than decades
More on expectations and tests in Durability.
For business
Wood sells well as a gift and for personalisation. Because every piece is different, the same motif can look different on two boards. Put that in the product description, for example “grain and colour tone vary”. This way you avoid complaints about the “wrong colour”. And factor in white: with full-surface white on wood, ink costs and print time rise considerably.
Continue with: Varnish, Colour layers and the materials overview.