Grayscale, sepia, negative or pure two-tone, with brightness and contrast, adjusted while you watch.
Your images are processed on your device and never uploaded.
Drag and drop your images
or click to choose · Ctrl+V to paste (several at once, up to 50MB each)
Everything runs in your browser. Your images are never sent to a server.
MamePress takes the colour out of a picture and saves it that way, as grayscale, as pure black and white, as sepia or as a negative. The whole job runs inside your browser: nothing is uploaded to a server, so a private photo or a scanned document stays on your device. There is no account to create, nothing to pay, no limit on how many times you use it, and no watermark on the result.
| Effect | Result | Typical use |
|---|---|---|
| Grayscale | Shades of grey only | A black and white photo, a check before printing in mono |
| Sepia | Warm brown tones | An old-photo, vintage look |
| Invert (negative) | Light and dark, and colours, reversed | A film-negative look, white lines on black |
| Pure black & white | Two colours, no grey (saved as PNG) | Scanned documents, signatures, stamps, line art |
Most "black and white" converters give you grayscale: the colour goes, and every shade of grey stays. That is right for a photo and wrong for a scan, where the grey is the paper's shadow and the faint edge of every letter. Pure black & white leaves exactly two colours. Each pixel that is at or above the Threshold turns white and every other pixel turns black, and you move the threshold until the page is clean. If the threshold alone cannot separate text from shadow, Brightness and Contrast are applied before the split, and Auto levels sets them from the image on screen. The result is saved as PNG, which keeps the two colours exact.
Drop every page of a document at once. The first one opens, and you choose the effect and the threshold on it. Then press Save all … as ZIP to get every page with those settings in one file, or press Download image on each and the next page opens with the same settings; Skip to the next image passes over one you do not need. Only one page is on screen at a time, and the ZIP does not judge each page's brightness on its own: if your scans vary from page to page, go one by one and adjust the threshold as you go. A file that cannot be opened is skipped rather than stopping the run, and its name is listed on the page.
Averaging red, green and blue makes green, which looks bright, as dark as blue, which looks dark, and the picture goes flat. Grayscale here weights them the way the eye does (red 29.9%, green 58.7%, blue 11.4%), so the shading of the original survives. Strength mixes the effect with the original colours, for a half-faded look. To reverse only light and dark with Invert (negative), tick Make it grayscale before inverting. Transparent areas stay transparent.
The image is saved in the format it was opened in: JPEG stays JPEG, PNG stays PNG, WebP stays WebP. HEIC becomes JPEG, and AVIF, GIF and BMP become PNG, because a browser cannot write those formats, and pure black and white is always PNG; when the format is going to change, the page says so before you save. A PNG is written without loss. A JPEG is compressed once more when it is saved, and so is a WebP. A JPEG that is saved as a JPEG keeps the print resolution (DPI) recorded in the original.
Are my images uploaded anywhere?
No. Every effect is applied inside your browser, on your own device. Neither the original nor the black and white copy is sent to a server; there is no upload endpoint to send them to, so there is also nothing to delete afterwards.
What is the difference between grayscale and pure black and white?
"Grayscale" takes the colour out and keeps every shade of grey in between, so a photo still looks like a photo. "Pure black & white" leaves two colours and no grey at all: each pixel turns white or black depending on whether it is lighter than the threshold you set. That is what you want for a scanned document, a signature, a stamp or line art, and it is what most tools called black and white do not do.
How do I make a scanned page pure black and white, with no grey?
Choose "Pure black & white" and move the "Threshold" slider, which runs from 1 to 254. Pixels at or above it turn white and the rest turn black, so the grey cast of the paper disappears and the text comes out crisp. If shadows on the page go black, lower the threshold; if the strokes break up, raise it. When the threshold alone cannot separate them, use "Brightness" and "Contrast" too: they are applied before the split, so raising brightness lifts a shadowed page and raising contrast darkens faint text. The result is always saved as PNG, even from a JPEG, because a JPEG would put grey fringes back around every stroke.
Can I convert many images to black and white at once?
Yes. Drop them all at once, or choose several. The first one opens, and you set the effect on it. Then either press "Save all … as ZIP" to get every image with the same settings in one file, or press "Download image" on each: after every download the next image opens with the same settings, and "Skip to the next image" passes over one you do not need. Nothing has to be set twice, so pages of one document come out alike. The ZIP applies the same settings to every page and does not judge each page's brightness on its own; if your scans vary, go one by one and adjust the threshold as you go. A file that cannot be opened, is in an unsupported format or is over 50MB is skipped rather than stopping the run, and its name and the reason are listed on the page.
Which formats does it read, and what is saved?
It reads JPEG, PNG, WebP, AVIF, GIF, BMP, HEIC and HEIF, up to 50MB a file. A JPEG, PNG or WebP is saved in its own format. HEIC and HEIF come out as JPEG, and AVIF, GIF and BMP come out as PNG, because a browser cannot write those formats; the page says so before you save. "Pure black & white" is always saved as PNG. An animated GIF is turned as its first frame, and the animation is not kept.
Does it lose quality?
A PNG is written without loss, so nothing changes beyond the effect itself. A JPEG or a WebP is compressed once more when it is saved, at quality 0.92, and because the effect rewrites every pixel the whole picture goes through that compression. To avoid it entirely, start from a PNG. A JPEG that is saved as a JPEG keeps the print resolution (DPI) recorded in the original, so a 300dpi scan is still a 300dpi scan.
Can I adjust brightness and contrast?
Yes. "Brightness" and "Contrast" each run from -100 to 100 and start at 0, where they add nothing. They are applied before the effect, so with "Pure black & white" they move where black and white split, and with the other effects they change how dark the result is. "Auto levels" works the two values out from the darkest and lightest parts of the image on screen and puts them on the sliders, where you can keep them or move them further. "Reset brightness and contrast" puts both back to 0. In a batch, both carry over to the next image like every other setting.
How do I invert the colours of an image?
Choose "Invert (negative)". On a colour picture every colour turns into its opposite, so red becomes cyan and blue becomes yellow. If you only want light and dark swapped, tick "Make it grayscale before inverting" next to it.
Why does the grayscale look more natural than a simple filter?
Averaging red, green and blue makes green, which the eye sees as bright, as dark as blue, which it sees as dark, and the picture goes flat. This tool weights them the way the eye does (red 29.9%, green 58.7%, blue 11.4%), so the shading of the original survives. Transparent areas stay transparent, so a cut-out PNG stays cut out. "Strength" mixes the effect with the original colours, from 0% to 100%.
Can I get the colour back, or colourise a black and white photo?
Not from a saved file: turning an image black and white throws the colour information away, so keep the original. Before you save, setting "Strength" to 0% brings the colour back. This tool does not colourise black and white photos.
Once it is black and white, frame it with theimage cropper, turn a sideways scan with theimage rotator, or make the file smaller with theimage compressor. All three run in the browser too.
