Black and White Converter
Make an image grayscale: turn a photo or video black and white, then tune brightness, contrast and gamma until the grays look right. Files stay on your device.
What is a grayscale image?
A grayscale image shows only brightness, no color, so every pixel is some shade between black and white. Photographers usually call it black and white, though strictly speaking a black-and-white picture has just the two tones and no grays.
This black and white picture converter keeps the full range of grays, whether you give it a photo or every frame of a video.
How is a color photo converted to black and white?
A grayscale conversion gives each pixel one brightness value. Simply averaging red, green and blue looks wrong, because the eye sees green as far brighter than blue. That's why standard conversions weight the channels.
This converter uses the Rec. 601 luma weights, about 30% red, 59% green and 11% blue, which is the mix analog color television used for its brightness signal. Greens and yellows come out light, and deep blues come out dark.
How to make a photo black and white
The page opens on the Black and white preset. Saturation sits at its lowest, which drains every color to gray, and Contrast gets a small boost.
Brightness changes the exposure. Contrast spreads tones away from mid gray or pulls them in toward it, and Gamma lifts or sinks the midtones while pure black and white stay put.
Hue still matters once the color's gone. It turns the colors before they become gray, a lot like a colored filter on black-and-white film, so it changes which parts of the photo end up light or dark.
Settings for a dramatic sky, a smooth portrait, film noir and high key
For a dramatic sky, set Hue 60 and Contrast 0.2. Turning the colors first sends blues toward magenta and reds toward yellow, so the sky and foliage darken while skin and brick get lighter, much like a red filter on film. For a smooth portrait, try Hue 30 and Gamma 1.15. Reddish blemishes move closer to the lightness of the skin around them, and the lifted midtones keep the face open.
For film noir, go with Brightness -0.15, Contrast 0.35, Gamma 0.8, which gives you pools of black around a few bright shapes. For high key, use Brightness 0.15, Gamma 1.4, Contrast -0.1. Most tones move into the light grays and only the darkest details survive.
If you want two pure tones at the end and not a range of grays, save the result and cut it with Threshold Image.
Why do red and green come out the same gray?
The conversion only keeps brightness, and colors of equal brightness land on the same gray. A red flower against green leaves can merge into one flat area.
Turn Hue before the color drains out to pull them apart. At 60 degrees reds come out lighter than greens. At -60 they come out darker, with skies going pale and reds nearly black.
Saving a grayscale photo
The GIF encoder here matches colors at 32 levels a channel. A smooth gray sky will break into visible steps unless the Dither box in the GIF export stays ticked, which it is by default.
For stills, JPG handles grayscale photos well and keeps the files small. Save a PNG when the picture's headed for print or another round of editing.