How to use
Choose a static image. Enter contrast from 0 to 200; a blank value uses 100. Generate, compare and download. Any new edit clears the confirmed result until you generate again.
Examples
Grayscale combines red, green and blue using weights 0.2126, 0.7152 and 0.0722. The same rounded value is written to all three channels. At contrast 100, an opaque red pixel (255, 0, 0) becomes approximately (54, 54, 54). A neutral (128, 128, 128) pixel stays neutral at every contrast setting.
How the output works
Contrast scales the distance from mid-gray. At 0, every visible pixel becomes gray 128; at 200 the distance doubles and values outside 0–255 are clipped. Start at 100 and increase gently. Strong contrast can remove subtle shadow and highlight detail. This is grayscale photography, not a two-color threshold, stencil or vector tracer.
Limits and troubleshooting
PNG output keeps the decoded dimensions and transparency. A transparent PNG remains transparent rather than gaining an artificial checkerboard. The comparison uses the same generated image that is downloaded. No sharpening, restoration, resizing, batch conversion or cloud processing is included.
Saving and compatibility
Use a valid static PNG, JPEG or WebP up to 20 MB, 24 megapixels and 12,000 pixels per side. Animated images and unsupported formats are rejected. The browser applies JPEG orientation on decode. The original stays unchanged; camera metadata and exact archival profile fidelity are not preserved.
Frequently asked questions
Are files uploaded?
No. Image decoding, editing and exports run in this browser. Only bundled application assets and fonts are loaded from this site.
Why did the download become unavailable?
Editing invalidates the previous output. Generate again to ensure that the downloaded file matches your current settings.
Will my work survive a reload?
No. There is no project storage. Save your result before reloading, changing language or leaving this page.
What does Clear do?
It clears the image, settings and output. Remove clears only the current source image and its output, preserving other settings.