Savvy video enthusiasts know that watching a flat-panel TV in a dark room can cause eye strain or fatigue. To make the experience more comfortable, you need to place a bias light behind the screen. CinemaQuest has been making Ideal-Lume bias lights for 19 years, but the company recently replaced its fluorescent models with two new models that use LEDs as the light source.
Traditionally, bias lights have been spec’d to exhibit D65 white at 10% of the display’s peak brightness. However, those specs were established many years ago when small CRT monitors were used in color-grading suites. Now, reference monitors—and consumer TVs—are larger, and they have high dynamic-range capabilities. The color spec is still D65 white, but the brightness is commonly spec’d at 5 nits.
However, colorists spend about half their time looking at still frames, while consumers look almost exclusively at moving images, which can lead to eye fatigue more quickly than still images can. As a result, the brightness of a consumer bias light should be somewhat higher than 5 nits, though no definitive standard has been established yet.
Then there’s the color-rendering index (CRI), which is a quantitative measure of how a light source impacts the apparent color of objects it illuminates compared with a reference light source. The closer to 100 a light source’s CRI is, the more accurate will be the color of objects it illuminates.
The Ideal-Lume Standard and Pro both use LEDs as the light source, and both exhibit D65 white. Unlike the previous fluorescent versions, the new models can be dimmed with the included dimmer (60 Hz power systems only). This allows the user to set the brightness to the most comfortable level. Other improvements over the previous generation include greater efficiency, cooler operation, longer life, and lower prices.
Both models are about two feet long, which is large enough for free-standing TVs up to 73″ (diagonal). For dark walls and larger screens, especially if they are wall mounted, multiple units behind the sides, top, and/or bottom of the screen can be linked together with optional cables.
The Ideal-Lume Standard and Pro models look identical when viewed under room lighting. The base is extruded aluminum, and they come with a power cord, dimmer, and mounting hardware. The two models use different LEDs to achieve different spectra and CRI ratings.
This is the spectrum of the Ideal-Lume Standard LED model as measured by Independent Testing Laboratories. It closely resembles the spectrum of many LCD and OLED TVs.
This is the spectrum of the Ideal-Lume Pro LED model as measured by Independent Testing Laboratories. It is closer to the spectrum of the CIE reference illuminant, which is why this unit has a higher CRI than the Standard model.
The Ideal-Lume Standard carries a price tag of $64 with a CRI of 93. The Ideal-Lume Pro, which is intended for color-grading suites and other super-critical viewing environments, costs $300 with a CRI of 97. Both offer a lifespan of 50,000 hours and consume a mere 7 watts, and both come with a 5-year warranty.
For more info, visit the CinemaQuest website.