How to make a photo black and white
Upload an image and the Adjust tab opens with Grayscale set to 100 percent, so the preview is already black and white. Download it as it is, or move the slider down to blend some of the original colour back in. Around 50 to 70 percent gives a faded, vintage feel that keeps a hint of colour.
Grayscale removes colour information and keeps brightness. Each pixel becomes a shade of grey based on how light it looks to the eye, so a bright yellow turns into a light grey and a deep blue becomes dark. The image keeps its original dimensions, and PNG files keep their transparency.
Getting a better black and white result
Colour photos often look flat once the colour is gone, because two different colours of similar brightness turn into the same grey. Raising contrast to around 110 to 130 percent in the same tab separates tones and gives deeper blacks and cleaner whites. A small brightness change can rescue an image that looks muddy.
Black and white suits portraits, architecture, strong shapes and scenes with interesting light and shadow. It also hides distracting colour casts from mixed indoor lighting. Images whose main interest is colour, such as sunsets or flowers, usually lose more than they gain.
Grayscale for documents and printing
Converting scans, receipts or forms to grayscale before printing can save colour ink and make them easier to read. For black and white printing it also lets you see in advance how a colour image will look on paper. The saved file is still an RGB image with grey pixels, which every viewer and printer handles normally. PNG stays PNG and other formats are saved as JPG.