Lightroom: 4K display uses wrong display size on Mac

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  • Problem
  • Updated 3 years ago
With LR 6.3 on a MacPro, LR Help->System info reports 2x the display resolution, and the "auto" Preview size is also 2x.

For example, selecting a 3008x1692 Display size with Mac Preferences->Display, results in a LR "size" of 6016x3384, in System info and "auto" Preview size. See Help->System info below.

With a normal (non-4K) monitor, the LR "size" always matches the display resolution.

I'm running Yosemite 10.10.5 on a MacPro (mid-2010), a Dell P2715Q monitor (4K, 3840x2160) with a HD 7970 display board, connected with a mDP to DP cable.


Lightroom version: 6.3 [ 1052427 ]
License: Perpetual
Operating system: Mac OS 10
Version: 10.10 [5]
Application architecture: x64
Logical processor count: 12
Processor speed: 3.3 GHz
Built-in memory: 32,768.0 MB
Real memory available to Lightroom: 32,768.0 MB
Real memory used by Lightroom: 1,199.9 MB (3.6%)
Virtual memory used by Lightroom: 2,727.1 MB
Memory cache size: 990.0 MB
Maximum thread count used by Camera Raw: 12
Camera Raw SIMD optimization: SSE2
Displays: 1) 6016x3384

Graphics Processor Info:
AMD Radeon HD Tahiti XT Prototype OpenGL Engine

Check OpenGL support: Passed
Vendor: ATI Technologies Inc.
Version: 4.1 ATI-1.32.25
Renderer: AMD Radeon HD Tahiti XT Prototype OpenGL Engine
LanguageVersion: 4.10

Application folder: /Applications/Adobe Lightroom
Library Path: /Volumes/Data/LR Catalogs/Photos LR6.lrcat
Settings Folder: /Users/XXX/Library/Application Support/Adobe/Lightroom

Installed Plugins:
1) Aperture/iPhoto Importer Plug-in
2) Canon Tether Plugin
3) Facebook
4) Flickr
5) HDR Efex Pro
6) HDR Efex Pro 2
7) jf Metadata Wrangler
8) Leica Tether Plugin
9) LRT Export 4
10) Nikon Tether Plugin

Config.lua flags: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: Built-in Output
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 44100
Build: LR5x102
CoreImage: true
Photo of Bob Squires

Bob Squires

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Posted 4 years ago

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Photo of Bob Squires

Bob Squires

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I tried LR 6.0, 6.1.1 and 6.3 running under El Capitan.

Same problem, the Display size reported by LR is always 2x the real display size. It causes problem with the Library module - cannot "fill" the screen in Loupe view, etc.

Any suggestions?
Photo of seanhoyt-dot-art


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This is a huge issue. My computer runs faster at 4k 3820x2160 (more space) compared to the two notches down 3008x1692 and 2560x1440 specifically because of what you are pointing out. Lightroom is rendering HUGE previews to screen in Library and Develop modes. In highest setting, the speed increases because LR is using smaller res images BUT the OS X and LR interface is comically small. (27" 4k screen, El Capitan, LR up to date)