"Kolrosing" is the Scandinavian term for a technique in which one makes cuts in wood with the point of a knife and then fills them with pigment. Traditionally, materials such as charcoal, soot, or scraped and pulverized dry bark from pine or willow were used. This technique originates from the Sami people, who inhabit the northernmost part of Sweden.
Kolrosing is used as a decorative method on various wooden items such as Kuksas, spoons, bowls, and other handmade wood carvings.
It's important to note that kolrosing differs from chip carving. In kolrosing, cuts are made in the wood and filled with pigment, while chip carving involves removing material, often in the form of triangles.
Every type of wood is suitable for applying kolrosing. In lighter woods such as maple, birch, lime, and willow, the design appears more contrasting.
In softer woods, the result may be less precise. Opting for a harder wood, such as fruitwood (apple, pear, cherry), allows for very fine and detailed work.
For ring-porous woods like chestnut, elm, oak, and ash, it's important to be aware that the pores will also fill with pigment.
Kolrosing is, so to speak, the icing on the cake and is one of the final steps in completing our spoon. Successful execution requires careful preparation.
It is essential to have a stable and clean surface.
Ensure that the spoon is completely dry. The surface you are going to kolros should be as smooth as possible, which can be achieved by using finishing cuts, sanding, and/or polishing.
A well-finished surface of the spoon has the advantage that the knife glides smoothly over the surface during kolrosing.
Polishing is an essential step to achieve a smooth and even surface. This is accomplished by rubbing with a smooth stone, a piece of antler, or the back of a metal spoon. In this way, the fibers are compressed, making it easier to draw.
Even after the pigment and oil are applied, rubbing is done again over the created cuts to effectively hold the pigment. This friction contributes to strengthening the adhesion of the pigment and enhances the overall durability and appearance of the final artwork.
For the kolrosing process, you can choose to draw some designs on paper beforehand or apply the design directly freehand onto the spoon. Stencil paper or baking paper can also be useful for transferring your drawing.
However, it is crucial to consider the direction of the wood fibers. For instance, if using a braiding pattern, it's important to place your design diagonally across the fibers.
You have the option to practice on a dry piece of wood before applying your skills to a spoon. As you gain more confidence, you can try the technique on an actual spoon. Practicing on dry wood provides an opportunity to become familiar with the technique and develop your skills before applying it to the final piece.
It is essential to work with a sharp pencil with a graphite value of 2B when drawing the design on wood. Pencils that are too soft can smear the graphite too quickly, resulting in an unwanted gray haze. On the other hand, pencils that are too hard may cause the drawing to remain visible after applying oil. My personal preference is to use a mechanical pencil.
While erasing is possible, a kneaded eraser is preferred as it leaves no traces and absorbs the pigment beautifully.
Cutting TechniqueA correct cutting technique is crucial in kolrosing. Ensure that your knife is always at a 90° angle to the surface.
The pressure you apply is of utmost importance; consistent light pressure results in even cuts that form beautiful lines. Experiment with the pressure to create both thicker and thinner lines.
The push cut is a safe method for cutting small and intricate pieces. Caution is needed with the pull cut, especially for long straight lines, as slipping can occur. If you find the knife getting stuck, reduce the pressure and proceed carefully.
For working on challenging and rounded shapes, the stabbing method is a handy technique. Mastering these various cutting techniques contributes to achieving beautiful and precise results in kolrosing.
Practice makes perfect.
Using a chip carving knife is not recommended as it is too narrow. A wide cutting angle is needed to nicely open up the cut, while a chip carving knife goes deep but not wide.
There are various kolrosing knives available on the market, and it's a matter of personal preference which one works best for you. Personally, I prefer a Mora 120, while others like Lydia Lathem use a longer pick knife from Ben Orford, and Adam Hawker makes his own knives from old metal drills.
It is important to experiment and discover which knife is most suitable for your kolrosing technique.
For filling the carved surface, you can use any material with a finer grain than 1 mm. Traditionally, like the Sami people, you can work with charcoal or bark pigment. Additionally, there are alternatives such as coffee grounds, cinnamon powder, bister, paprika powder, and so on.
It is important to carefully rub the carved surface with a generous amount of pigment, ensuring that the pigment reaches into all the grooves.
Personally, I prefer extra finely ground cinnamon, and sometimes I roast it to achieve a darker color. Experimenting with different pigment materials gives you the opportunity to create unique effects and develop your own style when kolrosing.
After filling the cuts with pigment, we proceed to burnishing/polishing, which can be done either before or after applying the oil.
This step closes the lines, resulting in a smoother finish.
Next, we wipe off excess oil and pigment from the spoon with a clean cloth. Allow the spoon to dry completely to allow the oil to polymerize.
It's important to use a strongly polymerizing oil that fully cures, such as walnut oil, linseed oil, hemp oil, tung oil, and so on. These oils fixate the pigment and provide better protection to the surface.