Threshold Image Converter
Turn photos, scans, signatures, logos, and drawings into crisp black-and-white images with an adjustable threshold and instant private preview.
Create clean two-color images
Precise threshold control
Choose the exact brightness cutoff from 0 to 255 and preview every adjustment immediately.
Multiple brightness methods
Use perceived luminance, RGB average, or an individual color channel to isolate the detail you need.
Private PNG export
Processing stays in your browser, preserving hard black-and-white edges in a lossless PNG.
Image threshold settings
| Setting | Result | Best use |
|---|---|---|
| Low threshold | More pixels become white | Faint scans and light handwriting |
| Medium threshold | Balanced black and white | Logos, documents, and signatures |
| High threshold | More pixels become black | Bright photos and strong silhouettes |
| Invert | Swaps black and white | Stencils and negative-style artwork |
How it works
- 1
Upload an image
Choose a photo, scanned page, signature, logo, or drawing.
- 2
Set the threshold
Move the cutoff and select the brightness source that preserves important details.
- 3
Download PNG
Save the resulting pure black-and-white image.
What is image thresholding?
Thresholding classifies every pixel as black or white according to its brightness. It is useful for cleaning scanned text, preparing signatures, simplifying logos, making stencils, and creating high-contrast masks.
Start near 128, then lower the value when light details disappear or raise it when the background remains too visible. Perceived brightness usually gives natural results because it reflects how human vision weights red, green, and blue.
Frequently asked questions
What does an image threshold do?
It converts every pixel to either black or white according to a selected brightness cutoff.
Which threshold value should I use?
Start at 128 and adjust while watching the preview. Scans often need a lower or higher value depending on lighting.
Can I threshold a signature or logo?
Yes. Thresholding is useful for signatures, line art, logos, documents, and stencil preparation.
Is my image uploaded to a server?
No. The conversion runs locally in your browser.
Threshold Image Converter last reviewed: Aug 2, 2026.