HackSpace magazine

Wood-block-printing with lasers

By Dr Andrew Lewis. Posted

Printing from woodcuts (also known as block-printing) is one of the oldest printing techniques for paper and textiles. It’s also one of the most versatile methods of printing, offering more opportunities for experimentation than other similar techniques like lino printing. Different combinations of wood grain and ink can create different effects on finished prints. If you’re just starting out with printing, learning the skills needed to carve the block by hand can be a huge stumbling block, and having the right type of wood to carve cleanly can be expensive. If you’re lucky enough to have access to a laser cutter, you can start experimenting much more quickly by using that to carve your wood-blocks.

There’s plenty of room for experimentation with block-printing, but you can’t just dive in without preparing your workspace. You’ll need to be working in a clean, dry, well-lit space with flat surfaces and enough room to lay out your tools comfortably. You will also need somewhere to lay out wet prints while they dry, and plenty of cleaning supplies to deal with any spills as they happen.

The first step to creating your print is to figure out a suitable design. Wood has a grain, and the fineness of the grain will determine how much detail you’ll be able to include in your print. Fine lines and dots are likely to break away from the block very quickly, particularly if you’re using coarse-grained wood. Bold text and simple shapes are a nice starting point if you’re nervous, but don’t be afraid to push the limits of where you feel comfortable. You’ll be raster etching the wood, so open up your favourite editor and get designing. If you want to find some inspiration, have a look at oldbookillustrations.com, and you can search for woodcuts from old books and get an idea of what’s possible.

Keeping your workspace free of dirt and ink splashes is important

Transfer your design onto the wood-block using a laser cutter and K40 Whisperer. Remember that the printing process will reverse the printing plate, and that black areas of the image will be engraved into the wood. Chances are that you’ll want to reverse the image and invert the colours so that your drawn lines will be proud of the wood, not engraved into it. Assuming that you’re using a K40 laser, set the power to about 20%, and the speed to 200 mm/s. Your choice of wood and the components in your laser will have an effect on this setting, so you might need to do some experimentation to get the best etch. It’s worth taking your time setting up the wood in the printer, making sure that the focal distance and alignment are correct, and that you have plenty of airflow and ventilation in place to deal with the smoke created by woodcuts. Never leave the laser unattended when it’s working, and check constantly to make sure everything is proceeding as planned.

The laser will probably boil out some sap from the wood and deposit some smoke stains, so your printed block will need a clean before it’s used. A wipe with a solvent might be enough, or some gentle lapping with fine sandpaper might be better if your wood is a little bit uneven. If you’re going to glue your block down to a larger piece of wood to keep it flat, now is the time to do it.

Block printing is a great way of making custom cards or invitations

Inking the block is an art in itself. Normally, you’ll apply ink with a roller. It might seem like a trivial act, but loading the roller with an even amount of paint and controlling the pressure you apply from the roller to the block is something that takes a bit of practice. Start by applying some ink to a glass sheet. Block-printing ink is very thick, and it should just sit there on the glass without spreading out. Use a putty knife or spatula to get your ink spread roughly into a line, and then use the roller to start working it into an even coat on the glass. Use a piece of scrap paper or card to take any excess from the roller, and then roll it through the ink again while applying light pressure to take an even coat of ink onto the roller. Transfer the roller over to the printing block, and roll it over as evenly as you can. You want to avoid getting ink anywhere that it isn’t supposed to be, particularly around the edges of the wood-block. 

Carve, Ink, Print, Repeat

You should now have an inked block, and an excess of creative energy. Take a piece of thick paper and carefully lay it down on top of the printing block. It’s important not to move the paper once it’s touching the block, so a gentle touch and a little bit of practice might be needed to get your paper to sit straight. Apply another couple of sheets of thick paper on top of the first sheet. These sheets of paper serve a dual purpose. They protect the sheet you’re printing with from any smudges or ink transfer from the back, but more importantly, they add some flexibility behind the printing sheet, allowing it to deform slightly into the printing plate and pick up more ink when pressure is applied. Using too many sheets will lead to smudging, but one or two sheets of paper will make the ink transfer more evenly onto your printed piece.

Not all woods engrave the same on a laser engraver

How you apply pressure to the back of the paper will depend on what tools you have available. If you have access to a book press or roller press, you can get an even result with minimal effort. You can also use a hard rubber brayer or even a rolling pin if that’s all you have access to, but you’ll need to practice applying even pressure and rolling across the back of the paper in a uniform way to get the best results. If you have a manual die cutter, like the Sizzix Big Shot, you can use layers of thin craft foam and plywood to shim the paper and printing plate so that it passes through the machine’s fixed roller with sufficient pressure to transfer the ink when you turn the handle. 

Carefully peel the printed sheet from the wood-block, and flip it over to admire your work. Place the paper somewhere flat to dry, or if you’re stuck for space, hang it vertically on an indoor washing-line with pegs.

After you’ve made a few successful prints, you’ll probably start thinking about getting more adventurous and using different colour combinations or techniques. You can apply multiple different colours to a single block using small rollers, or print multiple times onto the same sheet with different blocks. You can turn everything upside down, and use printing blocks as stamps to create patterns on textiles or other materials. If you’re going to think about stamping, you can experiment with etching thin EVA foam glued to a wooden base to make a softer stamp. It isn’t really wood-cutting at that point, but it is good fun!

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