: Where does Photoshop get the pixel ratio from? I have images that I generate via ImageMagick that are supposed to have a non-square pixel ratio. Photoshop seems to be able to detect that the

I have images that I generate via ImageMagick that are supposed to have a non-square pixel ratio.

Photoshop seems to be able to detect that the pixel ratio is not square (I see that there is a custom pixel ratio set up) but I cannot tell where the ratio came from, as it is different from the resolution I set.

So the question is - where does Photoshop get the pixel ratio from?

This the output from identify:

Image: strange.png
Format: PNG (Portable Network Graphics)
Mime type: image/png
Class: DirectClass
Geometry: 734x995+0+0
Resolution: 23.63x36.52
Print size: 31.0622x27.2453
Units: PixelsPerCentimeter
Type: TrueColor
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Pixels: 730330
Red:
min: 25 (0.0980392)
max: 255 (1)
mean: 182.009 (0.71376)
standard deviation: 87.5167 (0.343203)
kurtosis: -1.61776
skewness: -0.485718
entropy: 0.342994
Green:
min: 38 (0.14902)
max: 255 (1)
mean: 188.828 (0.740503)
standard deviation: 72.5125 (0.284363)
kurtosis: -1.26545
skewness: -0.481082
entropy: 0.357498
Blue:
min: 0 (0)
max: 255 (1)
mean: 150.706 (0.591004)
standard deviation: 110.202 (0.432163)
kurtosis: -1.67965
skewness: -0.294347
entropy: 0.346663
Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 173.848 (0.681756)
standard deviation: 91.3995 (0.35843)
kurtosis: -1.14615
skewness: -0.580943
entropy: 0.349052
Rendering intent: Perceptual
Gamma: 0.45455
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 1021x1103+218+58
Origin geometry: +218+58
Dispose: Undefined
Iterations: 0
Compression: Zip
Orientation: Undefined
Properties:
date:create: 2016-01-26T09:42:53+01:00
date:modify: 2016-01-26T09:42:53+01:00
png:bKGD: chunk was found (see Background color, above)
png:cHRM: chunk was found (see Chromaticity, above)
png:gAMA: gamma=0.45454544 (See Gamma, above)
png:IHDR.bit-depth-orig: 8
png:IHDR.bit_depth: 8
png:IHDR.color-type-orig: 2
png:IHDR.color_type: 2 (Truecolor)
png:IHDR.interlace_method: 0 (Not interlaced)
png:IHDR.width,height: 734, 995
png:oFFs: x_off=218, y_off=58
png:pHYs: x_res=2363, y_res=3652, units=1
png:sRGB: intent=0 (Perceptual Intent)
png:text: 2 tEXt/zTXt/iTXt chunks were found
png:tIME: 2016-01-26T09:42:53Z
png:vpAg: width=1021, height=1103
signature: 4be6c7cdfbf701380737943a2363a747c47da9281caba9fe053da6ca0e89b2e3
Artifacts:
filename: strange.png
verbose: true
Tainted: False
Filesize: 114KB
Number pixels: 730K
Pixels per second: 365.17GB
User time: 0.000u
Elapsed time: 0:01.000
Version: ImageMagick 6.9.2-10 Q16 x86_64 2016-01-21

and the custom pixel ratio automatically set up in Photoshop is 1.533, although, given a resolution of 23.63x36.52, I should have something like 1.545, which is 36.52 / 23.63.