Print Resolution Calculator
Calculator
This page computes the minimum resolution for a given print size at a given viewing distance based on the viewer’s visual acuity. To use set the print size (in inches), and the viewing distance to generate the resolution requirements.
Print and Viewer Settings
| Print Size | ||||||||
| Size | x | |||||||
| Standard Sizes | ||||||||
| Viewing Distance | ||||||||
s | ||||||||
| Distance Presets: | ||||||||
| Visual Acuity | ||||||||
| Acuity: |
| |||||||
Required Resolution
| PPI: | |
| Minimum resolution: | |
| Resolution in Megapixels: |
Help, Notes, and Theory
Usage
For basic usage, the calculator can simply be used by specifying a print size. It will default to a viewing distance equal to the diagonal of the print and to a viewer with “normal” 20/20 vision.
For more advanced considerations, the viewing distance, and view’s visual acuity can be adjusted to affect the calculations. For example, a photographer intending to print images for sale may want to assume a higher visual acuity (20/15 or even 20/10) in their calculations to insure that their images are pleasing to the widest possible audience.
Alternatively, the distance setting can be varied when the photographer/printer has control over the viewing distance. For example, a print hung behind a couch/sofa or other obstacle that prevents someone from approaching as close as an image hung in a more open setting like a hallway.
Theory
The minimum resolution needed to produce a print that doesn’t appear blocky or pixelated is dictated by the smallest detail the viewer can resolve. This in turn is based on the viewer’s visual acuity and the distance from which they are viewing the print. The better the viewer’s vision or closer they view the print from the finer the detail must be, and thus the higher the resolution requirements are.
This calculator assumes that a viewer with 20/20 vision can resolve a blur-spot 1-arc minute (1/60th of a degree) in diameter.
Notes
Distance: The minimum viewing distance that is expected.
Print Size: The print dimensions in inches.
Set to Std. Distance: Uses the traditional photographic viewing distance rule of thumb, the diagonal of the print, to set the distance based on the specified print size.
PPI: The number of dots per inch that can be resolved by a person with 20/20 vision standing at the distance specified.
Minimum Resolution: The lowest resolution that should be used to print an image of specified size with the minimum required viewing distance.
Resolution in Megapixels: The required resolution of the image in mega pixels.
Note 1: Most camera manufacturers computer depth of field and similar values using the equivelent of 20/60 vision.
