Would it be wise to create a dark-themed admin screen? As in not just the header/footer/menu area is dark (eg, black / dark grey), but the areas where content are as well.
Does it put more strain on user to do admin stuff on a dark screen than a light (white/grey) one?
I'm not a big fan of dark background and light text but if you use right shades it's fine more here. I would say that it depends on clients (admins). It should be comfortable for them on the first place.
Using a defined switch of 'theme' for admin/editing sections on a site can be an effective way of clarifying a different 'state' for user interaction.
Bear in mind though that as pointed out by Grzegorz Gajos' link above, white text on a black background will possibly prove more difficult to read and may even cause discomfort for some viewers over a sustained period. Subtlety tweaking the tint of the background and text can improve legibility considerably however; have a looks at themes for Sublime Text (http://colorsublime.com/ - some good and bad examples here btw) and editors such as MOU for examples of using dark backgrounds effectively.
The most websites and also applications are very bright. So a dark application / website is something special.
I like a dark design. It creates a mystic atmosphere, which I really like.
But here it is important for what you use the application. The admin screen should have the same design lines like the whole application.
Dark applications are heavy. They maybe deppressed and makes a mood about comlexity. Bright design looks very light and easy to handle.
But IMO, dark designs can generate an extremly good atmosphere.
If you have an application which will be used for all the peoples out there, I wouldn't use a dark design. But it is for a special topic, for example gaming, movie etc., a dark design looks very good.
Also bright colors are even more effective on a dark background and you can create really stunning effects while playing with colors.
Do you maybe have some additional information about your target application?
A website which I love because of the dark design is GO! Experience design. It makes a mystic atmosphere and plays also with colors.
Dark screens are more likely to show reflections of light from other sources, making them more difficult to read. On the other hand, working in a dark room at night, dark themes are easier on the eyes than bright screens.
Is there a reason you can't offer more than one theme so users can select the one they prefer, or make their own?
Assuming this is web based, there are developments in progress to allow you to capture the current ambient light level, which you could use to alter the theme to match that.
From a usability / User Experience view then the answer is dark text on white is more readable in most cases. Exceptions are where people work in dark conditions, like musicians, video editors and coders doing an all night session. In those conditions dark backgrounds reduce eye strain and prevents the display being over bearly bright. Most Sat Navs switch between a night and day views for that reason.
From a visual design point of view it's down to how well the design is put together and the views of your target audience.
So if your audience is a macho audience who work long hours into the night, then a dark background might be an option. Otherwise I'd try and stick with black on white.
