What Does Y Resolution Mean?

Y Resolution is the vertical half of a pair. It says how tightly an image's pixels sit along its up and down direction, counted as the number of pixels that fit into an inch or a centimetre of paper. In a coordinate system that direction is the y-axis, also called the vertical axis.

Which files carry it, and where the value comes from

The field belongs to the EXIF and TIFF metadata blocks, so you meet it in JPEG, TIFF and camera RAW files, in PDFs, and in anything exported by an image editor. Scanners write it, and video files in the QuickTime family, MOV and MP4, carry a vertical resolution in their video track too, where it is nearly always 72 and has no bearing on playback.

The number is declared by whatever produced the file rather than measured from the picture. Cameras write a fixed default. A scanner writes the density it really used. An editor writes the document resolution that happened to be set when the file was saved. Read it together with two other rows: Resolution Unit, which says whether the count is per inch or per centimetre, and X Resolution, its horizontal twin.

What a typical value looks like

A plain number, with the unit kept in the companion field. Common values are 72, 96, 150, 300 for print work and 600 or higher for scans. In the great majority of files it is identical to X Resolution, because pixels are normally square.

When the two differ, that is the interesting case: the pixels are not square, and the image will look stretched or squashed unless software accounts for it. A flatbed scanner can be set to sample at different horizontal and vertical steps. Old fax images are the classic example, storing fewer rows per inch than columns, which is why an unprocessed fax page can look vertically compressed.

Why it matters

Y Resolution decides how tall an image comes out on paper. An image 2400 pixels high at 300 pixels per inch prints exactly eight inches tall. The same file marked 72 prints over 33 inches tall from the same pixels, spread thinner and looking coarser.

The mismatch case is where the field really earns attention. If Y Resolution is half of X Resolution, layout and print software will place the image twice as tall as it should be, and the result looks stretched even though not a single pixel is wrong. Checking that the two values agree is a quick way to explain an image that arrives at the wrong shape.

As with its horizontal twin, the field changes nothing about the pixels themselves. Editing it neither adds nor removes image data and neither grows nor shrinks the file, and screens generally ignore it, which is why the number can sit there looking odd for years without causing any trouble. It carries no personal information of any kind.