Digital Projection's Screen Brightness Calculator:
A Useful Tool for Designing High-Impact Projection for Any Venue

The answers to the questions of how bright a projector needs to be, or how big a screen can be employed on a job, depend on viewing distance, ambient light level, content to be displayed and desired image brightness. DPI created the Screen Brightness Calculator to assist in defining the optimum mix of screen size, screen gain, projector lumens and contrast, for any venue.

To use DPI's Screen Brightness Calculator, the only factors you need to know in advance are the ambient light level that will be falling on the screen and the display objectives for the venue. Armed with this information, the calculator can guide you in selecting the perfect combination of projector lumens and screen size and type, to create optimum imagery in your applications.

The Screen Brightness Calculator can also assist you in determining screen dimensions (height, width and diagonal) for any aspect ratio screen. Simply select the required screen aspect ratio and define any one of the three screen dimensions, and the remaining two dimensions will calculate automatically.

To put the Screen Brightness Calculator to work, select your projector resolution and the required screen aspect ratio, then simply type the relevant numbers into the yellow boxes. Your goal is to match screen dimensions, screen gain and projector lumens, such that the system delivers enough Ft. Lamberts to overcome the venue ambient light level and produce suitable environmental contrast ratios. Target Ft. Lamberts for different types of venues are provided as examples within the Screen Brightness Calculator.

Experiment with the Calculator by trying different screen gains, screen sizes, aspect ratios, projector lumens and venue ambient light (falling on the screen). Notice the impact these factors have on image performance.

When using the calculator, be aware that projector brightness in lumens and the projector's contrast ratio must be as accurate as possible. Some manufacturers exaggerate these values in their specifications. Don't use "spec" data if it is suspect, use real data. Additionally, projectors that use Metal Halide lamps produce much less light when calibrated to D6500. Finally, all projection lamps lose light output as they are run through their useful life. Thus, the actual values you create using the Screen Brightness Calculator should be 25-to-50% higher than the target values referenced in the Calculator. This will help assure the projected imagery remains high impact through the entire life of each lamp.

CLICK HERE to start using the Screen Brightness Calculator.

IMPORTANT: The Caculator is a Microsoft Excel file and uses "macro" functions. In order for it to work properly, the Excel program on your computer must be set-up properly. This is done by setting Excel's Security settings.

If you don't know how to do this, follow these simple instructions (BEFORE opening the Calculator):

• Open-up Microsoft Excel
• In the Toolbar, click-on TOOLS
• Drag your cursor down to MACRO, follow the arrow, and click-on SECURITY
• In the SECURITY LEVEL tab, choose Medium. This setting will give you the option of enabling or disabling macros found in any file you open
• Click OK and exit Microsoft Excel.
• Click-on the link (above) to DPI's Screen Brightness Calculator
• Before the file opens, you will be prompted to either enable or disable the file's macros. Click-on ENABLE MACROS.
• You are now able to use the Calculator

If you have any further problems, please contact your IT Manager or your DP Regional Market Development Manager.