This is higher than the resolution in MP number because a Bayer sensor loses some resolution in the demosaicing process, and some more with the low-pass filter over the top.įor the calculation here, I’ve assumed the Bayer patter and low-pass filter reduce the sensor’s resolving power by 25%, but I would note this isn’t something to be taken as gospel. The final line in the Required Resolution section is the estimated resolution of a Bayer sensor to achieve the calculated image resolution. In practice, this isn’t true at all, as both the Bayer pattern sensor and the low-pass/anti-aliasing filter placed over the sensor reduce the sensor’s actual resolution somewhat. That is it assumes there is no resolution loss between the native resolution of the sensor, and the image it produces. The third line makes a naïve jump from image resolution to sensor resolution. See the chart below for approximate conversion to other scales. In a lot of ways you can stop here and go with these numbers, and things should be okay. The first 2 line cover basic image information. The results are all functionally the same but present the information in various ways. This option ends up suggesting about 42% more resolution than its counterpart suggests. I’ve provided an “inscribed pixel” checkbox in this version of the calculator that causes the calculator to assume the image pixels are inscribed in the circle of confusion instead of circumscribed. I would consider this the absolute minimum tolerable resolution for that size print and viewing distance.

Footīy default, the calculator assumes the pixel is circumscribed around the disk of confusion. 20/60 was included since that’s what most camera manufacturers’ seem to use when computing the circle of confusion and depth of field scales. Presets are set based on what I find typical for a lot of uses. Pretty standard, range is 8-inches to 10-feet. The larger print value (1 sq ft) is meant to be used to calculate the resolution need per square foot of a very large print, see the Big Prints section at the end. Print sizes are assumed to be in inches unless otherwise noted. However, even at the minimum distance of 8 inches, the error is well below 0.001% of the actual value which is more than sufficient for these calculations. Note, this is of course a skinny triangle approximation. That gives us the diameter of a disk shaped “pixel” for the print that can’t be better resolved without moving closer or having better vision. The “spot size” on the print is then calculated using s = x × tan(0.000290888209 × f s), where s is the spot size, x is the distance to the target and f s is conversion factor from 20/20 to one of the other visual acuity ratings. The fundamental assumption is that the disc of confusion for a person with 20/20 vision is equal to 1 arc-minute (1/60 th of a degree) in diameter. This is little more than a transform from angular acuity of human vision, to spatial resolving power at the print converted to mega pixels. The required resolution is derived simply from considering the visual acuity of the human eye at a given distance and given acuity standard. Comments ( 4 ) Notes and Theory Required Resolution Theory.See notes and theory below the calculator for the details. Further it calculates the aperture that will be diffraction limited for that resolution. Armed with this knowledge, everything else is simple math.This calculator computes the required minimum resolution needed to satisfy human visual acuity for a given size print at a given viewing distance. A still-acceptable quality requires that the print resolution should be no less than 150 DPI. Photographic quality (at an arm's length viewing distance) requires that the print resolution should be no less than 300 DPI (dots per inch), which can also be written as 300 PPI (pixels per inch). The only special knowledge we needed to solve the problem was about quality, which was easily found on the web. I've created the handbook Standard photographic print sizes for defining standard photo print sizes, which can be edited to provide missed sizes. We want to choose the maximum photo print size that allows us to print the digital image without quality loss.

The photo print size name defines the linear dimensions of a photo print – for example, 4''圆'' or 4R photo print size means that the photo print has 102x152 millimeters dimensions. We have a digital image with the known size in pixels, for example 3264 x 2448, and we also have a known set of standard photo print sizes used by photographic printing services. The first calculator recommends the photographic print size for given digital image dimensions in pixels. This article is about the relation between a digital image size in pixels and the photographic print size.

Print resolution calculator