Apply grayscale, sepia, invert, brightness, contrast and saturation to any image.
Applied in your browser — the image is never uploaded.
How is a colour image converted to grayscale?
Use the Rec. 709 luma weights: 0.2126 red, 0.7152 green, 0.0722 blue. Averaging the three channels equally makes greens look unnaturally dark, because the eye is far more sensitive to green than to blue. Pure green becomes 182, not 85.
Understanding your result
The luma weights are what separate a good grayscale conversion from a poor one. Averaging the three channels equally treats a saturated green and a saturated blue as equally bright, which is badly wrong perceptually — green contributes roughly 72% of perceived brightness and blue only about 7%. Using the Rec. 709 weights keeps foliage light and skies dark, matching how the scene actually looked. The fixed filter order also matters: applying contrast before brightness gives a different result from the reverse, so a documented order makes stacked adjustments reproducible.
Formula and method
Grayscale uses the Rec. 709 luma weights: 0.2126 red, 0.7152 green, 0.0722 blue. Saturation interpolates each channel away from that luma value. Brightness multiplies, and contrast scales each channel about the 128 mid-point. Filters apply in the order grayscale, sepia, saturation, brightness, contrast, invert.
Assumptions and limitations
These are global adjustments applied to the whole image — there is no masking, no selective editing and no curves or levels control. Brightness is a simple multiplication rather than an exposure adjustment, so heavily overexposed areas clip to white and cannot be recovered. For serious photo editing, a dedicated editor with non-destructive adjustment layers will do considerably better.
Worked example
Pure green converted to grayscale becomes a light grey of 182, not the 85 a flat average of the three channels would give — because the eye is far more sensitive to green than to red or blue.
How to use this tool
- Choose your image.
- Tick the effects you want and adjust the sliders.
- Pick an output format.
- Download the filtered image.
Common mistakes to avoid
- Expecting to recover detail from areas already blown out to white.
- Stacking sepia on top of grayscale and expecting the original colours back.
- Pushing saturation far above 150%, which produces harsh colour banding.
- Re-saving a JPG repeatedly while experimenting.
About the Image Filters & Effects
This tool applies classic image adjustments — grayscale, sepia, invert, brightness, contrast and saturation — directly to the pixel data and bakes them into the exported file. Because the maths is done in JavaScript rather than through CSS filters, the result is identical in every browser.
Who should use this tool
Anyone adjusting a photo quickly without opening an image editor.
Benefits
- Filters are baked into the file, not just displayed.
- Grayscale uses proper luma weights, so greens do not go too dark.
- Filters stack in a fixed, predictable order.
- Identical results in every browser.
Practical use cases
- Converting a photo to black and white.
- Giving an image a vintage sepia tone.
- Brightening an underexposed picture.
- Desaturating an image for use as a background.
Frequently asked questions
Why does grayscale not just average the three channels?
Because the eye is far more sensitive to green than to blue. A flat average makes foliage look unnaturally dark; the Rec. 709 weights produce a conversion that matches perceived brightness.
Are the filters baked into the downloaded file?
Yes. They are applied to the pixel data before export, so the effect travels with the file rather than depending on how it is displayed.
In what order are filters applied?
Grayscale, then sepia, saturation, brightness, contrast, and finally invert. A fixed order means stacking several adjustments gives reproducible results.
Can I undo the filters later?
Not from the exported file — the change is destructive. Keep your original and re-run it with different settings if you want to experiment.
Is my image uploaded?
No. The pixels are read and rewritten entirely in your browser, so the image never leaves your device.