Understanding Photometric Lighting

Even though 49% of all electrical consumption worldwide is dedicated to motors, one of the most life-altering, irreplaceable miracles of electricity is the ability to illuminate our world. Imagine life without the convenience of flicking a switch to light our workplaces, our homes, our lives-the importance of lighting can never be overstated. According to the U.S. Energy Information Administration, residential sector electrical consumption for lighting (75 billion kWh) has dropped to 5% of total residential sector electricity consumption in 2019. We can thank the advent of LED lighting for this minuscule fact.
Photometrics is the science of the measurement of visible light that exists between the ultraviolet and infrared wavelengths on the lighting spectrum (electro-magnetic scale) in relation to the human eye. In actuality, visible light to the human eye only occupies a very small percentage of the entire width of the electromagnetic spectrum, but within that narrow band exists everything that is important to us regarding lighting.
We study this fascinating science in the better interest of enhancing our environs with the use of light. We break it down further with three distinct types of lighting that can be applied within any one room. They are;

General Lighting – recessed flood lighting and ceiling mounted fixtures
Task Lighting – recessed spot lighting, desk lamps, undercabinet lighting
Accent Lighting – table lamps, wall sconces, bookshelf or art highlighting

Each of the three types of lighting is used functionally and artistically to create the all-important ambiance of a room. The best lighting plans incorporate all three agendas in a workable combination of functions. It is quite common the lines between any two of these types of lighting blur when serving double duty. For example, recessed accent lighting of artwork on a wall or over a mantle often has some general lighting characteristics due to bounce-back or luminous spill over of light. It can be argued a stunningly beautiful chandelier has to ability to serve all three!
In furtherance of this end, lighting engineers use a wide variety of lamps for general, task and accent lighting, each with different beam angles, depending on the objective at hand.

Very Narrow Spot (VNSP) – 7 degrees or less
Narrow Spot (NSP) – 8-15 degrees
Spot (SP) – 16-22 degrees
Narrow Flood (NFL) – 17-35 degrees
Flood (FL) – 36-45 degrees
Wide Flood (WFL) – 46-59 degrees
Very Wide Flood (VWFL) – 60-160 degrees and beyond

The primary source of light in a room is referred to as the general light. This allows for ingress and egress, work station illumination and is often quite different from most mood lighting. The 360 degree glow of a typical Edison lamp (known as A-19) is the workhorse of general lighting. In reality, any lamp with a wide beam of light up to 160 degrees makes good general room lighting (VWFL). The switch that controls these lights is often not a dimmer (however dimmers are mistakenly used for general lighting) and might stand alone or be the first in line when multiple switches are ‘ganged’ together to produce a row of three, four or more switches/dimmers.

When it comes to reading, cooking, sewing, writing, applying make-up, shaving, work benches and task lighting, a wide assortment of fixtures aid in this objective. Floor lamps, table lamps, recessed lighting, drop lights, swing arm lamps, adjustable recessed lighting-these are all forms of task lighting. Narrow floods and flood lamps serve these fixtures best. Task lighting often is found to have its own dedicated switches or dimmers but can be ganged like all the others.

The job of beautifying our lives with artistic use of lighting fixtures falls into the category of accent lighting. When a piece of art, whether 3 dimensional or wall mounted, requires specific illumination, accent lighting can be accomplished into a very poignant and dramatic statement with the interplay of dark and light and shadow. Track lighting was a 1970’s and 80’s version of moveable, adjustable accent lighting which allowed homeowner to create a variety of different scenes but served terribly as general room lighting. Hiding or concealing the source of light adds to the mystery of illumination and is one of the reasons why recessed lighting has become so popular when accentuation is needed. Very Narrow, Narrow and Spot lights dominate this category. The switching (or dimming) order for these features is generally found in the middle or at the end or a gang of switches.
Finding the right location on a wall for the controls is a key element in making general, accent and task lighting recognizable and useable. In this respect, good enough is never good enough. Some fore-thought of switch/dimmer layout in a multi-gang of devices goes a long way in assisting the homeowner in remembering the order. Exceed five devices in a gang and most of us struggle to recall which is general and which is task.

Years of compiled knowledge of general, task and accent lighting-a trademark of Lippolis Electric specialists-is often offered free of charge by simply calling our main number at 914-738-3550 and requesting a quote. Our best minds are on stand-by, waiting to hear from you.



Lippolis Electric, Inc. | 25 Seventh Street, Pelham, NY 10803 | 914-738-3550 | lippoliselectric.com