Notan Generator – Free Notan Art and Value Study Tool

Our free notan generator turns any photo or painting into a simple pattern of dark and light shapes, so you can check a composition before you pick up a brush. Make a two- or three-value notan, a value study with 3 to 9 steps of gray, an accurate grayscale version, or a color study limited to a few value bands. If you are new to the idea, our guide to notan art and notan design explains the background. Everything runs in your browser, and your image is never uploaded.

How to Use the Notan Generator

A notan or value study takes less than a minute:

1. Add your image. Click “Upload image”, drag a file onto the picture, or press Ctrl+V (Cmd+V on a Mac) to paste one. You can also paste an image link, or use “Take photo” on a phone or tablet.
2. Choose a mode. Start with “Notan 2 values”, then try three values or a value study.
3. Adjust. Move the threshold or click “Auto”, and use “Simplify (squint)” to merge small details.
4. Compare. In Split view, drag the divider across the picture to compare your study with the original.
5. Save or print. “Download PNG” saves the preview as you see it. “Print study sheet” creates a page with your study, the original, the value scale, and lines for notes.

The Five Modes Explained

Notan 2 Values

Every area becomes black or white. This is the purest form of notan and shows whether your main shapes still read when all detail is gone. The threshold decides where dark ends and light begins, and “Auto” picks it for you.

Notan 3 Values

Dark, middle gray, and light. Three values are enough to show light, shadow, and the transition between them, which is why many painters plan this way. Two sliders set the borders, and “Auto” finds both.

Value Study

Reduces the image to 3 to 9 steps of gray. With “Even steps”, the steps run evenly from black to white, so five steps use the lightness values 0, 25, 50, 75, and 100, like a printed value scale. With “Fit to this image”, each step sits at the average lightness of a group of values found in your picture.

Grayscale

An accurate black and white version that keeps the perceived lightness of every color. It works as a value checker: if two different colors turn into the same gray, they have the same value. Set “Simplify” to 0 for a sharp, unblurred version.

Color + Value

Keeps the hues of your image but limits its lightness to 3 to 9 bands, so you see your color plan and your value plan in one picture. With even spacing, each band uses its middle lightness, so even the darkest band keeps some color.

What Each Setting Does

• Threshold: sets the lightness, from 1 to 99, where one value group ends and the next begins.
• Steps and spacing: choose 3 to 9 steps or bands, spaced evenly or fitted to your image.
• Simplify (squint): blurs the image in every mode before it is divided into values, from 0 (off) to 10. Small details disappear and large shapes stay, much like squinting at your subject.
• Tone: shows the values in neutral gray (grisaille), warm brown (brunaille), or green gray (verdaccio), the classic colors of monochrome underpaintings. The lightness of each step stays the same. Tone is not used in Color + value mode.
• Invert, Mirror, and Upside down: swap light and dark, or flip the picture to see it with fresh eyes.
• View: Split with original, Side by side, Study only, or Original only.
• Grid: a rule of thirds grid (3 × 3), a 4 × 4 grid, a golden ratio grid, diagonals, or a custom grid with 2 to 12 columns and rows.

The value scale below the picture shows the values of the study (in Grayscale mode, eleven steps from L* 0 to 100) and how much of the picture each covers. Click a step to highlight its areas with stripes. The tool also reports the average value of your original and calls it low key (below 40), middle key, or high key (above 60). Point at or tap the picture to read the lightness of any spot.

What Is Notan?

Notan is a design concept about the balance of dark and light shapes in a picture. The word comes from the Japanese 濃淡 (nōtan), made of a character for dark or dense and a character for thin or pale. The idea reached Western art education through the American artist and teacher Arthur Wesley Dow, who studied Japanese art with the scholar Ernest Fenollosa in Boston.

In his book Composition, first published in 1899, Dow named three building blocks of a picture: line, notan, and color. His exercises asked students to design with flat areas of dark and light before adding anything else. Dow taught for many years at Teachers College, Columbia University, where Georgia O’Keeffe was among his students. The notan that art students practice today, as a design exercise in flat dark and light shapes, comes largely from Dow’s teaching. Our notan guide shows two-, three-, and four-value examples.

A good notan has a few large shapes, a balance of dark and light, and positive and negative shapes that interlock. Hokusai’s woodblock print The Great Wave off Kanagawa is a favorite example, because its wave, boats, and sky still read clearly in just two values.

Why Painters Make Value Studies

Value means how light or dark a color is. If the values are right, a painting reads well even in black and white, and many teachers say values matter more than color. Our guide to value in art covers the basics in more depth.

A value study is a small, quick plan of those values, made before painting to place the darkest dark and the lightest light, or during painting to check the work. Caravaggio and Rembrandt built whole pictures on strong value contrast, known as chiaroscuro. Load their paintings into the tool to see how few values hold the composition together.

How to Use Notan to Improve Your Composition

• Count the big shapes. In two values, a strong picture usually breaks into a handful of large shapes. Dozens of small spots call for more “Simplify” or a new design.
• Find the focal point. The strongest contrast between dark and light pulls the eye, so place it where you want the viewer to look.
• Check the balance. The value scale shows the share of dark and light. An exact 50/50 split can feel static, while one dominant value with a smaller accent often feels stronger.
• Use the grids. The rule of thirds and golden ratio grids show where key shapes and edges fall. Our article on composition in art explains these guides.
• Flip it. Mirroring or turning the picture upside down hides the subject, so you judge only shapes and values. Leonardo da Vinci advised painters to check their work in a mirror, because the reversed image makes mistakes easier to see.

How the Tool Works

The tool does not average red, green, and blue, because our eyes do not see them as equally bright: pure green and pure blue have the same RGB average, but green looks far lighter. Instead, each pixel is converted to CIE L*, a lightness scale from 0 (black) to 100 (white) designed to match human vision. Pure green has an L* of about 88, pure blue about 32. Painters who know the Munsell system can think of L* divided by 10 as a close match to Munsell value.

“Auto” uses Otsu’s method, a standard technique that picks the threshold that best separates the lightness values into two groups. For three values, it tests every pair of thresholds. “Fit to this image” groups the lightness values with k-means clustering. The squint effect is a smooth blur that scales with the image size.

Large images are scaled to 2,000 pixels on the longest side (1,400 on phones and tablets) to keep the tool fast, and downloads use this size.

Tips for Best Results

• Start simple. Begin with two values and only add steps when the big shapes work.
• Squint more for landscapes. Foliage, water, and clouds hold a lot of small detail. A Simplify setting of 4 to 6 often shows their main masses.
• Try both spacing options. “Fit to this image” works better than “Even steps” for very dark or very light pictures.
• Check your own work. Photograph your painting in even light and compare its study with the study of your reference.

Who Uses a Notan Generator?

• Painters plan and check values, from landscapes to portraits.
• Illustrators and printmakers design strong black and white images for ink or linocut.
• Art teachers show how masterpieces are built on dark and light shapes.
• Photographers and designers test whether an image works in black and white.

Your Images Stay Private

Your image is processed directly in your browser and never uploaded, so you can safely use personal photos, unfinished paintings, and client work. There is no sign-up, no watermark, and no limit on how many images you load. Only the sample paintings are loaded from Wikimedia Commons.

More Free Art Tools

All our tools are free, run in your browser, and need no account. See them all on the free art tools page.

• Photo to sketch: turn a photo into a pencil sketch or line art.
• Photo to coloring page: turn any picture into a printable coloring page.
• Image to pixel art: convert an image into editable pixel art.
• Art grid tool: put a drawing grid over any photo.
• Golden ratio overlay: check your composition with a golden spiral and rule of thirds.
• Perspective grid generator: print one-, two-, and three-point perspective grids.
• Paint by number generator: turn a photo into a printable paint by number template.
• Image color picker: find the exact colors in any photo or painting.
• Color name finder: get the name of any HEX, RGB, or photo color.
• Color wheel: find complementary, triadic, and analogous colors.
• Color mixer: mix paint or screen colors and find paint recipes.
• Color palette generator: create matching color schemes or a palette from an image.
• Color blindness simulator: see images and palettes as color blind people do.
• Art pricing calculator: find a fair price for your paintings and prints.
• Art prompt generator: get random ideas for drawing and painting.
• Random character generator: create an original character with traits and a palette.

Frequently Asked Questions

What Is a Notan in Art?

A notan is a design made only of dark and light shapes, usually in two or three values. Artists use it to plan or test the composition of a picture without the distraction of color and detail.

How Do I Make a Notan from a Photo?

Upload your photo to the notan generator above and choose “Notan 2 values”. Click “Auto” or move the threshold slider until the main shapes read clearly, and raise “Simplify” to remove small details. Then download the result as a PNG or print it.

What Is the Difference Between a Notan and a Value Study?

A notan uses only two or sometimes three values and focuses on the pattern of shapes. A value study uses more steps of gray, often five or more, and shows how light and shadow model the forms.

How Many Values Should a Value Study Have?

Three to five values are enough for most planning sketches. Use more steps when you want to study subtle changes in light, such as in a portrait. The tool lets you choose any number from 3 to 9.

How Can I Check the Values of My Painting?

Take a photo of your painting under even, indirect light and load it into the tool. Switch to “Grayscale” or “Value study” and compare the result with a study of your reference photo. Point at or tap any spot to read its lightness.

Can I Posterize an Image in Grayscale?

Yes. The “Value study” mode is a grayscale posterize tool made for artists. Unlike many posterize tools, which reduce each color channel separately, it divides the image by perceived lightness, so every step is a true value.

Is the Notan Generator Free?

Yes. The tool is completely free and needs no account.