Everything you need to know about Threshold
Threshold converts your image to pure black and white with no gray tones. Every pixel is evaluated against a brightness cutoff – pixels brighter than the threshold become white, darker pixels become black. This creates high-contrast graphic images, silhouettes, or masks.
Parameters
- Threshold
Sets the brightness cutoff point (0–255). Pixels with luminance above this value become white; those below become black. At 128 (middle gray), the image is split roughly in half. Lower values (50–100) result in more white. Higher values (150–200) result in more black. - Smoothing
Adds a soft transition zone around the threshold (0–0.25). At 0, the cutoff is perfectly sharp – pixels are either pure black or pure white. Increasing smoothing creates a gradual fade between black and white, producing a softer, less harsh result. - Mix
Blends the thresholded result with the original image. At 0, no change is visible. At 1.0, the full black-and-white threshold effect is applied. Use intermediate values for a partial effect that retains some original tonality.
How It Works
The filter calculates the luminance of each pixel, then compares it to your threshold value. With smoothing at 0, this is a binary decision. With smoothing enabled, pixels near the threshold get intermediate gray values based on how close they are to the cutoff.
Threshold Values
- 50–80 – Most of the image becomes white, only darkest areas remain black
- 100–128 – Balanced split, good starting point
- 150–180 – Most of the image becomes black, only brightest areas white
- 200–255 – Nearly all black, only extreme highlights remain
Tips
- Use for creating stencils, silhouettes, or high-contrast graphic art
- Great for making masks or selections based on brightness
- Add slight smoothing (0.01–0.05) to reduce harsh jagged edges
- Works best on images with clear subject/background separation