100% view in Lightroom shown smaller than exported file when opened with Apple preview app

[Peter_Hd7543]

Hi, I'm new here and have the following question:

When I import my pictures from various cameras into Lightroom, I choose 1:1 previews. When I later export the pictures e.g. as full size JPG and watch these files as 100% size in the simple Apple preview app, they appear much larger than shown in Lightroom in 100% view. I really would like to see the files in Lightroom at the same large size. How canI achieve that?? Btw. when I import the exported files into the Apple Photos app, they are shown as small as in Lightroom, too. 

Thanks a lot for your support!

Cheers, Peter

[Rob_Cullen]

To help achieve an answer you will need to quote-

1) PIXEL dimensions of the exported JPG files.

2) PIXEL dimensions of your computer monitor.

1:1 means 1 image pixel to 1 monitor pixel, so different screens will show 1:1 differently. And a Mac person might know if the Apple preview app scales images to suit the screen.

[Peter_Hd7543]

Ok, here we go:

It's a 14inch retina XDR-display with max 3024 x 1964 resulution. I had it running at 1800x1169 when I posted the message. Now, I played around with it. First adjusted to the max resultion (where noone can read anything anymore, but for the sake of testing), exported a file and suddenly see - in and out Lightroom same viewing size!? Then I adjusted to 1900x1200 - same result. So, I'm officially puzzled. Problem seems solved but I will report back if it happens again. If it does, maybe the solution is simply to resize the display and there you go. 

[JohanElzenga]

This has something to do with how MacOS deals with monitor settings. If you set your monitor to 1800 x 1169 pixels, and MacOS would simply use that, then everything sent to the screen would be upscaled to 3024 x 1964 pixels, because the hardware resolution obviously remains what it is. That would make it look soft and fuzzy, so MacOS uses a trick. It tells all apps that the screen is set to 2x (1800 x 1169) = 3600 x 2338 pixels. Now it can downsize that to the native 3024 x 1964 pixels, and so it remains sharp and crisp.

Unfortunately, not all apps deal with this correctly. This upsize/downsize trick should ideally only be used for interface items, not for images. If it is used for images as well, then displaying the image at 100% means the app will sent it to this virtual 3600 x 2338 pixels screen at 1 image pixel = 1 screen pixel. But then this gets downsized 3024/3600 = 0.84x. So your image is not really shown at 100% but at 84%. Unfortunately Lightroom is one of the apps that does this. Apparently Apple Preview works correctly.

[JohanElzenga]

BTW, I have discussed this issue with Adobe countless times, but either they don't think this is important enough to fix it, or they don't have a clue how to do that. I have given up on this. If you would set your monitor to exactly 50% of the native resolution (so to 1512 x 982 pixels in your case) then everything will look correct, because in that case 2x your screen setting is exactly the native screen resolution, so there is no downsampling.

[Peter_Hd7543]

Thank you!