Image Resolution and File Sizes Quiz – Test Your Photography Knowledge

6000 multiplied by 4000 equals 24 million pixels, which is 24 megapixels. Megapixels describe total pixel count in millions, so any sensor producing images of those pixel dimensions generates a 24-megapixel file.

300 dots per inch is the threshold at which individual ink dots become invisible at normal viewing distance for photographic prints. Below this number the print begins to look coarse; at 300 DPI the output appears as a continuous-tone image.

Dividing each pixel dimension by 300 gives the maximum printable size in inches at 300 DPI. A 6000-pixel width divided by 300 gives 20 inches; a 4000-pixel height gives 13.3 inches. The result is the largest size at which the print will maintain full-resolution quality.

Dividing 6000 by 300 gives 20 inches of width; dividing 4000 by 300 gives approximately 13.3 inches of height. These are the maximum print dimensions that keep the image at 300 pixels per inch throughout.

A large print is hung or displayed at a distance where the viewing angle subtends the same visual field as a small print viewed closely. At that greater distance, individual ink dots are too small to resolve, so a lower DPI produces the same apparent sharpness.

PPI, pixels per inch, describes how densely pixels are packed on a display screen and determines how sharp screen content appears. DPI, dots per inch, describes the density of ink dots in a physical print. The terms are often used interchangeably but technically refer to different domains.

Detail grows with the square root of the pixel count, so each step up adds less visible resolution than the last. Going from 12 to 24 megapixels is a clear jump, but going from 45 to 60 adds only about 15 percent more linear resolution. At most print and screen sizes that difference is very hard to see.

Each additional megapixel increases the amount of data written per frame, filling memory cards faster and requiring more storage. Larger files take longer to write to the card and to process, reducing burst depth and increasing editing and archiving time.