Quick answer: A palette knife is a blunt, flexible blade of steel or plastic set in a handle, used by painters to mix paint on the palette, scrape it clean, and move paint around. The closely related painting knife has a bent handle and a shaped blade and is used to apply paint directly to the canvas for thick, textured strokes. Neither is sharp; both are tools for pushing paint rather than cutting anything.
Ask “what is a palette knife” in a kitchen and you will get a different answer than in a studio. In cooking it spreads frosting; in painting it is the tool that keeps brushes out of the mixing process and, in the hands of impasto painters, replaces brushes entirely. This explainer covers the painting version: what the tool is, how it differs from a painting knife, what each shape is for, what it is made of, and what a palette knife does that nothing else in the kit can.
What Is a Palette Knife? The Precise Definition
Strictly speaking, a palette knife is a mixing and scraping tool. The blade is long, straight or slightly tapered, rounded at the tip, and set directly in line with the handle. It flexes a little under pressure but has no cutting edge. Its home is the palette, where it blends colors together, lifts a pile of paint to move it, and scrapes the surface clean at the end of the session.
In everyday use the term has stretched to include painting knives, the trowel-shaped tools with angled handles designed for applying paint to the canvas. Art stores, tutorials, and most painters use “palette knife” for both, and “palette knife painting” almost always means painting with what is technically a painting knife. This article follows that common usage but points out the difference where it matters.
Palette Knife vs Painting Knife
The two tools look similar and are often sold together, but they are built for different jobs.
| Feature | Palette knife | Painting knife |
|---|---|---|
| Handle | Straight, in line with the blade | Cranked (bent) so the hand sits above the surface |
| Blade shape | Long, straight, rounded tip | Diamond, trowel, teardrop, pear, or spatula shapes |
| Flex | Moderate; springy enough to scoop | Varies; fine tips are very flexible, large trowels stiffer |
| Primary job | Mixing, scraping, lifting paint | Applying paint to canvas, creating texture |
| Typical length | Blade 3 to 5 inches | Blade 1 to 4 inches |
| Used on canvas? | Occasionally, for broad scraping | Yes, this is its purpose |
The cranked handle is the giveaway. It lifts the hand so you can lay a flat blade on the canvas without dragging your knuckles through wet paint. A straight palette knife forces the hand nearly parallel to the surface, which is fine for mixing but clumsy for painting.
Most painters end up owning one straight palette knife for the palette and two or three painting knives of different sizes for the canvas. Sets that bundle both types are common, and the comparison of the best palette knife set looks at which combinations of shapes make sense for different kinds of work.
What Does a Palette Knife Do? Six Jobs in the Studio
The question “what does a palette knife do” has more answers than most beginners expect. Beyond mixing, the tool solves several everyday problems.
1. Mixing paint
A knife mixes faster and cleaner than a brush. Brushes trap pigment in the bristles and waste paint; a knife folds two colors together completely in a few passes and leaves nothing behind. Knife-mixing also protects brushes, which wear down quickly when ground into stiff paint.
2. Scraping the palette
At the end of a session, the blade clears mixtures off glass, wood, or plastic and gathers leftover paint into a pile for saving. A single razor-flat scrape leaves a glass palette clean enough to use again immediately.
3. Lifting and moving paint
Transferring a mixture to a palette cup, a storage jar, or another part of the palette is easiest with a knife. The same motion lifts a dollop onto the canvas when you need a large area filled.
4. Applying paint to the canvas
With a painting knife, paint goes on in slabs, ridges, and crisp lines that a brush cannot make. This is impasto technique, and it produces the sculptural surfaces associated with knife painting.
5. Scraping back the canvas
When a passage goes wrong, a knife held flat skims the wet paint off, leaving a thin ghost of color that is easy to paint over. Scraping back is also a deliberate technique: removing paint from a textured surface to reveal the layer beneath.
6. Applying gesso, texture paste, and gel
Thick grounds and texture mediums are spread with a palette knife like plaster, which gives even coverage and lets you build raised areas before painting begins.
Palette Knife Shapes and What Each Is Used For
Painting knives are sold in a bewildering range of numbered shapes, and the numbers mean different things from one brand to the next. Think in shape families instead.
| Shape | Description | Used for |
|---|---|---|
| Straight (palette knife proper) | Long, slender, rounded end | Mixing, scraping, lifting |
| Diamond | Symmetrical, pointed tip, wide middle | General-purpose application; the tip for detail, the sides for broad strokes |
| Trowel | Rectangular or wide blade, square or slightly rounded end | Flat drags, skies, water, large areas |
| Teardrop or pear | Rounded body narrowing to a point | Petals, leaves, curved dabs |
| Long thin (spear) | Narrow, flexible blade | Lines, stems, grass, edge work |
| Offset spatula | Small flat blade with a step in the handle | Tight corners, small panels, scraping edges |
| Round-tipped | Blunt oval end | Soft-edged marks, blending texture |
A sensible first set is one straight palette knife, one medium diamond (2 to 2.5 inch blade), and one small spear or teardrop (around 1 inch). Those three cover mixing, broad strokes, and detail. Larger trowels come into their own only on canvases above about 20 inches.
Materials: Steel, Plastic, and Wood
Stainless steel blade with wooden handle
The standard. Steel flexes predictably, cleans completely, holds a thin edge for lines, and does not react with oil paint or solvents. Better knives are forged from a single piece of steel that runs into the handle; cheaper ones have a thin blade spot-welded to a separate shank and can snap at the joint. Hardwood handles are often lacquered and riveted.
Plastic
Molded plastic knives are inexpensive and safe for children’s classes, but they are stiffer, snap at the neck, and cannot produce the fine line of a steel edge. Dried acrylic also grips plastic more than steel. They are acceptable for mixing and for texture pastes; most painters outgrow them quickly.
Carbon steel
Found on some older or specialty knives. Takes a finer edge than stainless but rusts if left wet and can discolor light paint mixes. Needs drying and occasional oiling.
Wood or bamboo
Occasionally sold as eco-friendly mixing tools. Fine for scraping and spreading gesso, poor for anything requiring flex or a clean edge.
What Are Palette Knives Used For Outside Oil Painting?
The tool crosses media more than people expect.
- Acrylic: Heavy-body acrylic and acrylics stiffened with gel take the knife as readily as oil. The main adjustment is speed, since acrylic skins in minutes. Working with the knife on canvas in acrylic is covered in the guide on how to use a palette knife on canvas.
- Watercolor and gouache: Rarely for application, but useful for scraping damp paper to lift pigment and create light lines (grasses, branches), and for spreading masking fluid.
- Encaustic: Heated knives spread and carve molten wax.
- Printmaking: Mixing and spreading ink on the slab before rolling.
- Mixed media and collage: Spreading adhesives, modeling paste, and texture gels evenly.
- Ceramics and sculpture: Smoothing slip and applying surface texture to clay.
In the kitchen the same word describes a flexible spatula for icing cakes, and the two tools are close enough that pastry knives have ended up in plenty of studios. The differences, and when it matters, are discussed in the comparison of a palette knife or spatula.
Why Painters Reach for a Knife Instead of a Brush
Understanding what the knife does differently explains when to use it.
- Texture. A brush drags paint into thin layers; a knife deposits it in relief. Light catches the ridges, so the surface itself becomes part of the image.
- Clean color. Knife strokes do not blend into each other unless you force them, so colors stay bright and separate. This is why knife paintings look so vivid.
- Speed. A 2-inch blade covers an area in one pass that a brush needs several strokes to fill.
- Edges. The thin edge of the blade produces a crisper straight line than almost any brush.
- Economy of decision. Because strokes cannot be fussed over, the knife forces simplification. Many painters use it to break the habit of overworking.
The trade-offs are real too: no fine detail, heavy paint consumption, long drying times for thick oil, and a surface that is harder to varnish evenly.
A Short History of the Tool
Knives have been part of the painter’s kit for as long as paint has been mixed by hand, but their use on the canvas is a more recent development. Nineteenth-century painters such as Courbet used knives to build rough, physical surfaces in landscape, and the practice spread as tube paint made thick, buttery color readily available. Impressionist and post-impressionist painters pushed it further, and by the twentieth century impasto knife work had become a recognized style in its own right rather than a shortcut. The cranked-handle painting knife, as sold today, developed alongside that shift, since a straight mixing blade is poorly suited to sustained work on an upright canvas.
How to Care for a Palette Knife
A good steel knife lasts for decades with minimal attention.
- Wipe immediately after use with a rag. Oil paint comes off with a dry wipe followed by a little solvent or oil; acrylic comes off with water if caught wet.
- Peel dried acrylic rather than scraping with another blade, which scratches the steel. Soaking in warm water loosens it.
- Dry carbon steel blades completely and rub a drop of oil on them. Stainless needs only drying.
- Check the handle joint occasionally. If the blade begins to wobble in the ferrule, a drop of epoxy fixes it before it fails mid-stroke.
- Store flat or blade-up. Bending a thin blade in a crowded drawer puts a permanent kink in it.
Buying Advice in Brief
When shopping, judge a knife on four things: a single-piece forged blade rather than a welded one, flex that returns to true when you release it, a comfortable handle that does not twist, and a smooth, burr-free edge. Price tracks these fairly closely. A few well-made knives serve better than a dozen flimsy ones, and sets are worthwhile only if the shapes in them are ones you will actually use.
FAQs
What is a palette knife used for in painting?
Mixing paint on the palette, scraping the palette clean, lifting and moving paint, applying thick textured strokes to the canvas, scraping back mistakes, and spreading gesso or texture paste.
Is a palette knife sharp?
No. The blade is blunt and rounded. It can leave a crisp line on canvas because the edge is thin, but it will not cut skin or paper under normal use.
What is the difference between a palette knife and a painting knife?
A palette knife has a straight handle and long blade for mixing. A painting knife has a bent handle and a shaped blade for applying paint to the canvas. In casual use, both are called palette knives.
Can you use a palette knife with acrylic paint?
Yes. Use heavy-body acrylic or add heavy gel medium, work quickly, and clean the blade before the paint dries on it.
What size palette knife should a beginner buy?
One straight mixing knife with a 3- to 4-inch blade, one medium diamond painting knife around 2 to 2.5 inches, and one small pointed knife around 1 inch.
Are plastic palette knives any good?
They work for mixing, spreading texture paste, and children’s classes, but they are stiff, snap easily, and cannot produce fine lines. Steel is the better long-term choice.
Final Thoughts
A palette knife is the quiet workhorse of a painter’s kit: it mixes, scrapes, lifts, and, in its painting-knife form, builds the thick textured surfaces that no brush can produce. Knowing which shape does what turns a confusing wall of numbered blades into a short, useful shopping list.
For a sorted look at the shape combinations worth owning, from a basic three-knife starter to larger sets for impasto work, the guide to palette knife sets for painters breaks down the options by blade shape, build quality, and intended use.
