Leopard Screen Sharing Image Quality

ScreenSharing within Leopard doesn’t give you the fine grained control over the remote screen’s image quality like Apple’s professional remote control application ‘Remote Desktop’. If you’re controlling the remote computer over a slower network, such as wifi, you’d want to change this setting to a lower image quality for faster screen refresh. Leopard’s built-in ScreenSharing only gives you two options: Adaptive or Full Quality. I haven’t tested Screen Sharing enough to understand what ‘Adaptive’ really does. I’m guessing it measures the network speed and adjust it on the fly. Whatever it means, this is good enough for me. I want to be able to control this myself.

To change this setting manually, open up the Terminal and type in the following command:

defaults write com.apple.ScreenSharing controlObserveQuality 2

This changes the controlObserveQuality setting within this plist file:
“~/Library/Preferences/com.apple.ScreenSharing.plist” file to 2, which is grey scale. To change it to a different resolution, substitute the number 2 with one of the following numbers.

1 = black and white
2 = grey scale
3 = 8 bit color
4 = 16 bit color
5 = full color


To answer Largo’s response below, ‘Screen Sharing’ is a system CoreService that resides here:

“/System/Library/CoreServices/Screen Sharing”

It’s basically just another hidden Utility application so you can drag it to your Dock to create a shortcut. But to specifically create a shortcut to a specific computer on your subnet, do the following:

1. Open up a Safari window
2. type in: vnc://ip.address.of.computer.

This is the IP address of the computer you want to create a shortcut to.
An example is: vnc://

3. Before loading that url, click on the small blue globe icon immediately to the left of the url and drag it to your Dock or any other place you want to save the shortcut.
4. To use the shortcut, just click on the icon in the Dock or double-click on the link you put somewhere.


3 thoughts on “Leopard Screen Sharing Image Quality”

  1. Tnx, this was very useful! Running my MacMini as my apartment “music generator” the Leopard screen sharing is helping me to have the ultimate remote control using my MacBook. Now a little bit speedier with this trick! A question little out of topic; do you know how to start the screen sharing with a script, shortcut or something? Sometimes it takes a few click to many to get hold of this “remote” using the Finder. Guess I’m getting lazy here.

  2. Is this built-in Screen Sharing the same that is called upon by iChat in Leopard to share the screen of an iChat buddy? If so, does applying this command in the terminal to change the default screen quality in the preference file also affect the default Screen Sharing quality in iChat? There seems to be no way in iChat itself to alter this.

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