Photo to Sketch Converter
Turn photos into pencil, charcoal, line-art or coloured-pencil sketches in your browser. Adjust line softness and darkness; save as PNG or JPG.
This converter redraws a photo as a hand-made drawing: a graphite pencil sketch, a smudgy charcoal study, clean black line art, or a coloured-pencil version that keeps the photo's colours. All the pixel maths runs on a canvas in your browser, so your photos never leave your device and there is nothing to install.
How to use this tool
- Choose one or more photos (JPG, PNG, WebP or anything your browser can display).
- Pick a style: pencil, charcoal, line art or coloured pencil.
- Set Line softness: low values keep fine detail such as hair and brickwork, high values give broad, soft strokes.
- Set Darkness for fainter or heavier lines, then download the sketch as PNG or JPG.
Formula
sketch = gray × 255 ÷ (255 − blur(255 − gray)), then out = 255 × (sketch ÷ 255)^γ
gray is the Rec. 601 luminance 0.299R + 0.587G + 0.114B. The inverted image is blurred with a three-pass box filter that approximates a Gaussian, wider for higher softness and bigger photos. This "colour dodge" turns flat areas into white paper and leaves grey strokes beside edges. γ = 1 + 3 × darkness deepens them. Charcoal uses a wider blur, γ = 1.5 + 4.5 × darkness, some of the original shading and a fixed grain; line art draws where the Sobel edge strength passes a threshold set by Darkness; coloured pencil multiplies the pencil result with a lightened copy of the photo.
Example
Take a dark pixel (gray 60) on the edge of a bright sky, where the blurred inverted neighbourhood is 125. The dodge gives 60 × 255 ÷ (255 − 125) ≈ 118. At Darkness 50%, γ = 2.5, so the stroke becomes 255 × (118 ÷ 255)^2.5 ≈ 37, a firm pencil line. A pixel inside the sky, gray 200 with a blurred inverted value of 55, gives 200 × 255 ÷ 200 = 255: blank paper.
Frequently asked questions
Are my photos uploaded?
No. The sketch is computed pixel by pixel by JavaScript in your browser, and the photo is never sent anywhere.
Which style suits my photo?
Pencil works well for portraits and pets, charcoal for moody landscapes and high-contrast scenes, line art for colouring pages and tracing, and coloured pencil when you want to keep the colours with a drawn look.
Why is my sketch almost blank?
Soft, low-contrast or very bright photos have few strong edges. Raise Darkness, lower Line softness, or try charcoal, which also keeps some of the shading.
Is this AI?
No. It is a fixed image-processing recipe, so the same photo and settings always give the same result and nothing is invented. Photos over 4,000 px on the long side are scaled down to 4,000 px to keep it fast.
Last updated: 2026-10-30