Image to Black & White Converter
Convert images to pure black & white (2-color threshold), not grayscale. Adjustable threshold for high-contrast effects.
What is True Black & White Conversion?
Black & White conversion (different from grayscale) produces a pure 2-color image where every pixel is either pure black (0) or pure white (255), with no gray values in between. The threshold parameter determines the cutoff: pixels brighter than threshold become white; darker become black. Used for: high-contrast artistic effects, preparing images for laser engraving or vinyl cutting, text recognition pre-processing, stencil templates, comic book / sketch aesthetics, screen printing source files, monochrome poster design. Different from grayscale (256 gray shades) and from monochrome (any single color + transparent). Pure binary B&W has the simplest pixel format possible.
How to use this tool
- Upload image — JPG, PNG, WebP — any common format.
- Adjust threshold — 0-255 slider. 128 is default (middle gray). Lower = more white pixels; higher = more black pixels.
- Preview live — Output updates as you move threshold slider.
- Download PNG — Pure black + pure white PNG, transparent if needed.
Threshold algorithm
For each pixel: brightness = (R + G + B) / 3
Then: if brightness >= threshold: white (255), else: black (0)
Result is binary image — each pixel either fully on or fully off.
Examples
- Laser engraving: Convert design to pure B&W for laser cutter
- Comic style: High threshold creates stark shadow/light effect
- Stencil prep: 2-color is ideal for vinyl or paper stencils
- Newspaper effect: Old-school print look
- Text contrast: Force text to pure black for OCR pre-processing
Tips & best practices
- Try thresholds 100-150 for natural-looking conversion
- For documents/text: higher threshold (180+) keeps text crisp
- For artistic effect: experiment with extremes (50 or 220)
- Different from grayscale — if you want shades of gray, use Image Grayscale tool
- Result is huge color reduction — great for compression in some contexts
Frequently Asked Questions
What's difference from grayscale?
Grayscale has 256 gray values (smooth gradients). True B&W has only 2 values (pure black or pure white). Much higher contrast, simpler file.
Best threshold for portraits?
Around 120-140. Lower thresholds make portraits ghostly; higher makes them too dark/silhouette-like.
Can I use for OCR?
Yes — B&W with threshold ~180 is excellent OCR pre-processing. Removes background noise, sharpens text.
Does it preserve transparency?
Yes — transparent pixels stay transparent; only RGB pixels get binarized.
Why is my image too dark?
Threshold too high — many pixels falling below threshold become black. Lower the threshold (try 100).
Output file size smaller?
Significantly — 2-color PNG compresses much better than full-color. 80%+ size reduction common.