Images DPI on Mac (72) and Windows (96)

[Doe Johns]

On Windows, the default screen DPI (aka PPI) is 96. On macOS, as far as I know, it is still 72 (note that we talk about images, not text!). Because of this, when I open InDesign on Windows and place there a 72-dpi image, it looks larger (compared to how it looks in web browser, hence web browser doesn't care about DPI) and blurry. My questions:

• Does it also mean that if I open InDesign on macOS and place a 96-dpi image there, it will look smaller compared to how it looks in web browser?
• And does it mean that if I create an InDesign document with 96-dpi images on my Windows PC, and then send it to a friend who use Mac, the images will look wrong (that is, smaller) to him?

I don't have a Mac, neither do my friends (just because it is quite pricy in my country), so I can't test it myself.

[rob day]

Hi @Doe Johns , starting with InDesign CS6, InDesign’s 100% view displays the page at its actual print size—the 100% view is not the same as Photoshop’s 1:1 image to monitor ratio. InDesign gets your monitor specs from the system and displays actual output dimensions—if you set your rulers to inches 1 inch will measure as 1 inch

When you place an image at 100%, its dimensions listed in the Transform Panel are also the print output dimensions. A 72ppi image would have a larger print output dimension than a 96ppi image, so the 72ppi image would display and print larger than the same image at 96ppi—this would be true on either platform. Here both images have the same 400 x 300 pixel dimension, but saved at different resolutions:

If I wanted to convert this page to an image for placing in a web page, I would have to export it to an image format. For exporting purposes InDesign has a Pixel Ruler Unit that measures 1/72", which is also true on both platforms. If I set my Rulers to Pixels the page measures 600px x 800px. If I Export the page to JPEG format with the Resolution set to 72ppi, the exported image will have a matching 600 x 800 pixel dimension: