Philips Master TL-D 90 Graphica

Standard Metal Hallide Lamp for indoor and outdoor lighting with 250W and 400W (E40 base), clear tubular bulb Features Clear tubular outer bulb Internal high pressure quartz discharge tube E40 base Color rendering index Ra of 65 Typical lifetime of 20.000 to 24.000 hours Luminous efficacy of 84 to 89 lumens/watt Cool white or daylight colour designation (4500 or 6700 K colour temperature) Horizontal operating position Lamp control gear Requires external gear (similar to mercury vapour lamps) and appropriate wiring: Philips BHL or compatible reactive inductive ballast with matching power rating Philips SI or compatible parallel ignitor for 5000 Volt pulses May require power factor correction capacitor for balancing line load

Understanding manufacturer data

Lamp light output is always measured in lumens. This is a way of measuring by averaging light output at a distance of 1 meter in an integrating sphere. This was carried out in lab environments and this information was mentioned in lamp datasheets and catalogues. While this information is accurate it should be considered only across similar lamp types.

Lamp life is presented in thousands of hours. It does not point at a specific moment when an installed lamp will not operate anymore but a statistical point at which some of the lamps may not operate, giving a rough estimate of useful life.

Ra8 colour rendering index, or simply colour rendering index is a way of expressing the typical colour rendering capability of a lamp. While it may be non-intuitive this is a computed average of brightness of certain coloured samples that are light by the lamp. The brighter they are, the more efficient is the lamp in this task. Most lamps do not have a continuous colour spectra so only some specific colours might look very bright and others look very dull. Colour samples are not intense reds, greens and blues but intermediately vivid colours that are focused on human skin colours and some fabrics or surfaces, meaning that a only very high colour rendering indexes are desirable for indoor home lighting. Sun light renders colours almost perfectly, having a value of 100 while typical lamps have a rendering index between 50 and 80, a good value being above 80 and a poor one below 50.

Colour temperature is another important detail. The value is presented in Kelvins and follows a theory that boils down to the fact that light can be produced by heating a metal up to a specific temperature. A camp fire releases light as the flame reaches around 1500-2000 degrees Celsius and a slightly higher value expressed in Kelvin. The designation is warm white for a value of around 2700 Kelvin, natural white with a value of around 3200-3500 Kelvin, cool white for a value of around 4000-4500 Kelvin, daylight for a value between 5000 and 5500 Kelvin, and cool daylight for a value above 6000-6500 Kelvin. There are cultural preferences that make some warm colour temperatures preferred in colder climates and cool colour temperatures in warmer climates. The most popular home lighting worldwide is mostly warm white, due to a comfortable, pleasant atmosphere that is close to the old incandescent lamp.

Technical details

Designation	Base	Lamp wattage	Luminous flux	Colour appearance	Colour Temperature	Colour Rendering Index (Ra8)	Life (to 50% failures)
MASTER HPI-T Plus 250W/645 E40 SLV	E40	250 W	20500 lm	Cool White	4500 K	65	20000 hours
MASTER HPI-T Plus 400W/645 E40 SLV	E40	400 W	35000 lm	Cool White	4500 K	65	20000 hours
HPI-T 1000W/645 E40 220V CRP	E40	1000 W	85000 lm	Cool White	4500 K	65	24000 hours
HPI-T 2000W/667 E40 220V CRP	E40	2000 W	189000 lm	Cool White	6700 K	65	24000 hours

Notes: "MASTER" designation should point at better performing lamps but it is meaningless in this lamp range.

Greatest features & flaws

Features	Flaws
High light output in very compact package	Serious glare risk
High efficiency, long life, average colour rendering	Quite expensive lamps
Mostly omni-directional light	Sensitive to operating position and unbalanced wearing
Quick lamp start	Slow restart, requires bulky, heavy, complex lamp gear