Photoshop displays images smaller than they actually are (at 100%)

[winterludes]

Some time ago, when viewing an image at 100%, photoshop would display the image the size it was, but after an update a few years ago, it has been showing images about half the size they actually are.  I've ignored it and worked around it, but I'm adding images to a website and I need to size them by eye and I'm tired of sizing an image 3 times, because i have to check how big it actualy is in preview and then guess again at a different size.  

I must have a setting wrong somehwhere?    Can anyone help?  Here is a picture of a simple image in photoshop at 100% and the same file opened in preview right next to it, you can see the file in preview is much larger than photoshop is showing it.  

Thanks for any help!

whitney 

[davescm · Accepted solution]

Photoshop 100% is not a physical size. At 100% zoom, it uses 1 screen pixel to display 1 image pixel. No scaling is involved, which is essential for critically reviewing image quality. So the higher density your screen pixels, the smaller the image appears on screen.
Many viewers and browsers, when using screens with high pixel densities (such as retina screens) scale the image to 200% so use 4 screen pixels to display one image pixel. This makes them look physically bigger on screen. If you want Photoshop to display the same way, use 200% zoom.

Dave

[winterludes]

Thank you that was very helpful!  I guess I am used to using Photoshop before all the high res screens, and at that time, 100% was what it looked like everywhere.  I set it to 200% and it's identical to the preview image.  

thanks again, you saved me tons of time!

[schroef]

It's also an osx issue, I believe this whole issie started with hdpi display like retina screens and such. But I've run into an issue today. Got this older m1 Mac mini and when I connect a 27" monitor which runs normally on windows at 100% 2560x1440 the images are scales by 50%. It's easily check by making an image at 72dpi with these dimensions. I just don't understand why apple doesn't show an option to make a none hdpi monitor show none hdpi. It took me some Houtse to find an app for osx which allows you to use a resolution of 2560x1440 in none hdpi mode.

EDIT
Found this app which "fixes" it. Its called BetterDisplay. The issue is that OSX is pixel doubling  even when i use a none scaled display ratio setting. I noticed when i saw screengrabs were 144dpi. Image in PS and Blender show at 50% when viewed at 100%

[D Fosse]

Dave is exactly right. This 200%-scaling that web browsers and image viewers do, is in fact the accepted industry standard workaround, to ensure that the same material can be used everywhere, regardless of what screen technology the user happens to have. Without this workaround, we'd need two separate internets: one for people with 4K/retina screens, and one for people with standard HD screens.

You should not size up your images! What you need to do is just set Photoshop to View > 200%. Then Photoshop will perfectly match your web browser.

If you want to dig deeper into this, there are ways to code websites so that two images are uploaded, and the browser chooses which one to display based on the screen resolution detected. But that is not something you can control. This has to be built into the site, as a special function, by the website creator.

[Nikolaus Macheck]

I for the first time have a 4K display too.

The problem is i guess, the MAC display settings. I downscale the UI to 2560 x 1440 (high res),

but that destroys the Photoshop 100% view. There should be an option to get there like in the past.

200% is just a slow and disppointing plan B...