100% display issue

[Marcel Janssen]

The actual size of a new RGB file doesn't match 100%. A new file of 1024 px is displayed much larger. When I measure it with Command-Shift-4, it measures 1326 px on the screen. Copying/pasting a screenshot also produces a much larger image of the screenshot in Illustrator.
I'm using version 30.

[HARSHIKA_VERMA]

Hi there,

Thanks for reaching out. Would you mind telling us the version of Illustrator installed on your machine and details of your operating system?

Please also share your screen resolution and the zoom percentage settings in Illustrator.

It would be helpful if you can share the screenshot or a screen recording of the problem.

We will be happy to assist you further.

Thanks,

Harshika

[Marcel Janssen]

I have Illustrator 30.0 actieve on a Mac with macOS 15.7.1 

See the srceenshot voor details. I make a screenshot of this website and past it in a new document (1024 x 1024px, rgb).

[Doug A Roberts · Accepted solution]

In Preferences > General, is 'Display Print Size at 100% Zoom' on or off?

[Marcel Janssen]

It is set to 'on'. And when set it to 'off' then a see the actual sice of the screenshot I paste in Illustator. 
This was happening after the upgrade to version 30.0 and never had any copy/past problems like this.  

[Doug A Roberts]

With 'Display Print Size at 100% Zoom' off, one monitor pixel should equal one image pixel at 100%.

With 'Display Print Size at 100% Zoom' on, your ruler units should match a real-life ruler at 100%.

If you're working for screens, it should be kept off.