Painting with a knife is a bit like putting butter or jam on bread and it produces quite a different result to a brush. Painting knives are excellent for producing a range of effects, from textured impasto work to sweeping areas of flat color, even tiny shapes of color.
A painting knife and a palette knife are very similar and many people use the terms interchangeably. However, there is a difference between the two knives.
WHAT IS A PALETTE KNIFE?
Strictly speaking, a palette knife is a long, straight blade or spatula that is used for mixing paints and scraping a palette clean. It is not for applying paint onto a canvas.
A palette knife can be made from metal, plastic, or wood and will either be completely straight or have a slightly cranked (bent) handle. The blade is very flexible, although plastic is less flexible than metal.
WHAT IS A PAINTING KNIFE?
A painting knife is most commonly made from metal and has a wood handle, although you can buy plastic painting knives for classroom use.
A painting knife has a large crank, or bend, in the handle, which takes your hand away from the painting surface. This design helps keep your knuckles out of any wet paint you've just applied.
The blade on a painting knife is somewhat flexible.
Painting knives come in numerous shapes (for example pear-, diamond-, or trowel-shaped) and are used for painting instead of a brush.
There is, of course, nothing stopping you from using a painting knife for mixing paint on your palette.
THESE KNIVES WON'T CUT
Although they're called a "knife," these tools are not designed to cut like a sharp knife or a craft knife. Rather, a painting or palette knife is a blunt-edged knife, like a butter knife, unless you specifically select one with a blade that has a sharp point.
PAINTING KNIFE SHAPES
Painting knives have the advantage over palette knives of coming in a range of sizes, more angular shapes, and with sharper points. Plus, the larger crank in the handle means there's less chance of accidentally rubbing your knuckles into wet paint.
If you are unsure whether you're going to enjoy painting with a knife, buy a cheap, plastic palette knife first and experiment a bit before upgrading to a wood-and-metal painting knife. The plastic one will always be handy for mixing paint (and it is much easier to clean than a brush).
WHY DO PAINTING KNIVES HAVE DIFFERENT SHAPES?
Different shaped painting knives obviously produce different effects.
A short blade produces angular strokes.
A long blade makes it easy to put down sweeps of color.
A rounded blade means you're less likely to accidentally scrape a hole into a canvas.
A sharp-pointed blade will allow you to scratch into the paint for sgraffito effects.
WHAT MAKES A GOOD PAINTING KNIFE?
Most of all, you're looking for a painting knife with a flexible blade that has a good spring or bounce to it. A painting knife with a narrower blade will bend more than a knife with a wider blade.
A very stiff blade is limited in the type of marks you can make with it, and a blade that is too flimsy or floppy is annoying as it is more difficult to control (and likely won't last as long). Metal knives generally have far more spring to them than plastic ones.
The handle should be smooth and comfortable to hold. You don't want to get splinters from a wooden handle, or have a knife that feels unbalanced. The blade of the knife should be well attached to the handle—you don't want it to rotate mid-stroke.
Most of the knives made by the major paint companies are equally good. Choose a painting knife by the shape and size, since these determine the effects you can create with it.
PAINTING KNIFE SETS
When purchasing painting knives, you will find many choices. Some manufacturers are better than others and if you're looking for a quality set of knives at an affordable price, we have some recommendations:
Liquitex Professional Freestyle Traditional Knives 6-Piece Ring Set (Buy from Amazon)
Conda Palette and Painting Knives (Buy from Amazon) : A reasonably priced assortment of eleven knives for practicing techniques.
Richeson Plastic Painting Knives (Set of 5) (Buy from Amazon)
Other good quality painting knives include those made by Loew Cornell (Buy from Amazon) and Bob Ross (Buy from Amazon).
HOW TO GET PAINT ONTO A PAINTING KNIFE
If you're able to get butter or jam onto a knife, then you already know what to do to get paint on a painting knife. There is no magic trick.
It's as easy as:
Scraping the knife across the surface of the paint on the palette so that it gathers up some paint.
Dipping it into the paint to get a bit of paint on the point or on the edge.
It is easier if your paint is thick, so don't add any medium or water to the paint to thin it. Use it as is straight from the tube.
CHOOSE YOUR PAINT (IT ALL WORKS!)
A painting knife can be used with any paint (including watercolor), but is particularly effective with paint that has a relatively stiff consistency to it, that retains its form and the marks you're making with the knife.
Tip: If you're using acrylics, you can add texture paste to thicken up the paint.
HOW TO HOLD A PAINTING KNIFE
Hold the handle firmly so you have a good grip. It doesn't matter where you arrange your fingers exactly. Holding it as though you are fencing, with your thumb on top is a good way to begin.
Adjust your grip for different techniques and details.
Use your wrist to change the angle of the knife in relation to your paint.
Remember that the knife can be used "upside down".
It will seem strange at first as it's quite different from using a brush. With practice, it becomes second nature.
TECHNIQUES FOR PAINTING KNIVES
Pick up some paint from your palette using the tip or the side of the knife, depending on the desired effect.
Use the long side of the blade to spread paint across your canvas as you would spread butter on a slice of bread.
Create a textured effect by pressing the blade with paint onto the surface.
Using just the tip of the blade will produce small dots.
Pressing the edge of the knife down will produce fine lines.
Pressing the blade flat down into the paint will produce ridges.
Scrape back into the paint to reveal underlying layers (called sgraffito).
See Mark Making with a Painting Knife for more results you can produce with a painting knife.
HOW TO CLEAN A PAINTING KNIFE
When it comes to cleaning, a painting knife has a decided advantage over a brush. The metal or plastic material is a breeze to clean up.
SIMPLY WIPE THE KNIFE CLEAN
Wipe any excess paint off with a cloth, then wipe the knife again with a clean cloth. Often, that's all you need to do to clean a painting knife.
Tip: Be sure to clean your knife between colors as you are working. Otherwise, you will find traces of unwanted hues throughout your painting.
If a paint has dried on the knife, you can often scrape it off using a damp cloth and another knife or a razor blade.
CARING FOR YOUR PAINTING KNIVES
If you're lazy about cleaning your tools, a painting knife is definitely more forgiving than a brush. A little dried paint on a knife has less of an effect than dried paint in a brush's bristles.
However, if a knife is made from steel (rather than stainless steel), it may rust if neglected. This is especially true if you enjoy plein-air painting in certain environments. For example, a steel knife used for a seascape will quickly rust if it's not cleaned after the exposure to sea mist.
If the blade of a painting knife ever breaks (though that does require some abuse), don't throw it away. See if you can't smooth the edge down into a new knife first. Worst case scenario is that it's only suitable for scraping.