View an image's metadata

Four values describe how a photo was taken, and together they explain most technical faults. The shutter speed is how long the sensor was exposed: at 1/15 of a second a hand-held shot is blurred by the slightest movement, at 1/500 a running child is frozen. The aperture, written as f/1.8 or f/8, sets how much of the scene is in focus; low numbers blur the background. ISO is the sensor's amplification, and above about 3200 the grain it adds becomes visible on most phones. The focal length tells you whether a wide or a long lens was used.

Looking up these numbers on pictures you like, and on ones that failed, is one of the quickest ways to learn what your own camera is doing in automatic mode.

People also open metadata to check a photo they have received: when it was taken, with what device, whether it has been through an editor. The data is useful for that, with two cautions. An empty result means little, because messaging apps and social networks remove metadata as a matter of routine. And a full result is not evidence either. Every field can be rewritten with freely available software, and a camera with a wrong clock produces wrong dates in good faith. Treat what you read as a lead to confirm some other way.

The first lines of the panel answer questions that come up in web and print work. Pixel dimensions tell you whether an image is large enough for its slot. The colour space shows whether a file is standard sRGB, a wide-gamut space such as Display P3, or CMYK prepared for a press, which explains why some pictures look dull or oversaturated in the wrong program. Bit depth separates ordinary 8-bit files from the 16-bit ones scanners and raw converters write. And the transparency line tells you whether a PNG really has an alpha channel or only a white background.