Print View vs Actual Size view

As others have noted Actual Size considers your Main monitor’s resolution and displays actual print output dimensions—if you show rulers and take a physical measurement 1" will equal 1". However, that only works if your document is displaying on what the system considers to be the main monitor, if you have a 2nd display running at a different pixel per inch resolution, and move the image to the 2nd monitor 1" will no longer measure 1". I have an iMac running at 109ppi with a 2nd moitor running at 98ppi—if I move an image displaying as Actual size to the 2nd monitor 1" measures as 1.112"  (109/98).

Print Size does not detect the main monitor resolution and instead uses your Preferences>Units & Rulers>Screen Resolution setting. If that setting is the same as your main monitor’s resolution, Actual Size and Print Size should display the same on the system’s main monitor. On a two monitor set up you could set Preferences>Units & Rulers>Screen Resolution to the 2nd monitor’s resolution, and Print Size would display 1" as 1" on the 2nd display, but not the main display. That might be useful when the setup is a small screen startup (i.e., a laptop) with a 2nd large screen monitor attatched where the editing is happening on the large screen.

Print Size view isn't really very useful IMHO but the key is you MUST enter the actual display resolution as JJMack has shown in your preferences:

Hi

The documentation on this is poor (non existent !) but as far as I can tell from experimentation on my Windows based system (other systems may differ):

Print size - this is calculated from a combination of :

a. The document ppi

and

b. The Screen resolution that you entered in Preferences >Units and rulers.  So Print size on screen will be accurate provided both of those are accurate.

Actual Size appears to work from a combination of :

a. The document ppi

and

b. The screen resolution as reported by the operating system (ignoring the manually entered figure).

In theory both should give the same result (provided the manual entry in preferences is accurate) because the operating system should report the same resolution as the screen resolution manually entered in preferences.

However on some systems (mine included using Windows 10 and Eizo monitors) there is a difference and Print Size , based on my manual entry of screen resolution, is the most accurate. This would suggest that the operating system is not picking up the actual ppi of my monitors correctly.

You can check which is accurate by turning on the ruler and putting an actual ruler up against the monitor to check. So in my case, I manually enter the screen resolution figure based on Eizo's specification and use Print Size.

Dave

Is you display size larger then the mural print size?  You use view Print size whey you have a large high resolution images that has many more pixels then your display has but the print size is smaller then your display's size.  If you have set your displaye resolution into your Photoshop preferences.  When you  use view Print Size Phtoshop will scale the image to fit on your displaye the image print suze so you get a good view of how it will look printed.

If you view actual size Photoshop will display your image's actual pixels the Image will not fit on your display  you will need to pan the image to inspect it for quality.  Viewed print size the quality will not be representative of the Print quality you not viewing your image.   Your are looking at a scaled version of your image