Contact us for free lighting advice & design today

Photometric Lighting Design


The study of light itself and how it enters the environment from the luminaire is what metric lighting is all about. It’s not something a home or business owner needs to worry about, because it’s knowledge that anyone working with luminaires needs. There is no other way to portray a lighting project with as much detail or accuracy as the photometric diagrams used by lighting designers.

What is photometric lighting study?

free-football-field-dialux-lighting-designThe perception of a light source is measured by photometry. The human eye is sensitive to certain wavelengths of light, and the light it sees changes between day and night. The exact wavelength a light source emits and where it is located is what photometric design takes into account.

A picture of what a set of lamps would look like to a person is provided by this. It takes a lot of math to make sense of it all. That mathematical knowledge comes from somewhere.

Researchers have charted how the human eye sees light. The criteria used by lighting designers are provided by this work. This standard gives the lighting designer a good idea of which lights are easy to see and which ones are difficult to see.

Lights with a wavelength of greenish-yellow are considered to be the brightest during the day. Greenish-yellow is a good choice for safety lighting.

Luminous flux

The total amount of light that a fixture emits can be adjusted for the human eye’s perception of the light. It is possible for a fixture to produce a lot of light, but not everyone will see it. Depicting how well a fixture creates perceivable light is what Luminous flux controls do.

Luminous intensity

Luminous intensity is the amount of light projected in a particular direction. It is possible for a light to produce a large amount of light, but not uniformly, so it will appear darker when viewed from different angles.

Creating a 3D lighting model


Lighting designers can create a 3D model of a set of luminaires with the help of photometric maps. Each luminaire uses IES data to show how it would look in a sports stadium, golf course, parking lot, industrial complex, large building, warehouse, factory or other location.

Lighting designers can provide their clients with several photometric images to help with the project. The 3D model accurately shows the transition from light to dark for each luminaire, showing where lighting is likely to gather and where dark spots can be found. The designer can create a bird’s eye view by mapping each fixture and drawing the extent of each fixture. This will give the client an idea of how far apart each luminaire is.

Lighting in the software

photometric-software-with-false-color-renderingThere are many ways to measure light. Computers and ease of use have made it important to record and standardize photometric data. Because of the large amount of light available, it was necessary to develop a standardized format. ies, the American Illuminating Engineering Society, stepped up to the plate as they worked to establish photometric charts.

The IES file format for recording photometric data was released in 1986. there are two important documents in the IES file. Lighting designers are able to determine the lighting pattern of a luminaire and how it will affect a space. The data used to determine the lighting pattern is generated by a goniophotometer. The intensity is measured by sensors around the interior of the building.

Why should we use photometric lighting design?

It is not clear how much of a difference a fixture can make. Increasing the wattage to overcome dead spots may be a good idea. Burning extra watts costs money and risks giving off too much light, which may be prohibited by local lighting ordinances, as well as the huge differences between fixture lighting patterns.

High pressure discharge lamps and metal halides are rapidly being replaced by light emitting diodes. There is a big difference between these two types of lamps.

The difference between discharge lamps and metal halides is that discharge lamps produce bright light that travels in all directions, while metal halides produce bright light that travels in only one direction. This has a significant impact on how photometric maps are produced when using light-emitting devices.

Considering these subtle differences makes the concept of photometry and drawings so important for lighting projects. It is a must for projects that require precise lighting. An experienced lighting company can provide cutting edge photometric concepts.

Photometric study is a measurement approach

People feel that lighting is something they don’t have to think about. It seems that lighting designers work from a sense of what the fixtures will look like. Reputable companies don’t just rely on their intuition to piece together a complex lighting project.

Making sure the client gets exactly what they are asking for is achieved through the use of photometric data. How do lighting professionals use photometric data? It takes a gonio photometer and the Illuminating Engineering Society of North America to get the full picture.

Preliminary evaluation of the venue

The designer begins a design by evaluating the areas they think are the most important. The stadium, architecture, landscape, and perimeter of the layout are included in this category. The key to an appealing plan is to maintain the areas and project enough light.

We have a good idea of how strong the light will be at certain distances. It gives designers a clear idea of how tall the lighting poles should be, how much power will be required and how many fixture will be needed.

Estimate the lighting outcome before installation

Modern photometric diagramming allows clients to see what their system will look like before it’s installed. There will be no surprises once the final product is put in place.

Some of the most important information in the lighting plan can be found here. On the right side of the schedule, there is a section that shows the lighting levels and distribution ratios.

Average, maximum and minimum are some of the foot candles measured in the plan. These numbers are used to ensure that the project meets building codes. The average is the most important. It is the perfect footcandle light reading for the entire project.

We can use the average/minimum footcandle light readings to see how different the darkest areas are from the average. The distribution of lighting in a space is shown by the max/min ratio. The purpose of the building code is to give the building an even distribution.

Applications of DIALux photometric lighting plan

Sports lighting

Our photometric technology can effectively analyze light levels on individual fields, full-size stadiums, and everything in between, making sports facilities one of the most common applications for photometric analysis.

The layout provides insight into the light level of the entire area and whether the layout will meet the lighting specifications for a particular sport or level of competition.

A tennis stadium may have eight courts and require club level lighting. If a photometric analysis is done, purchasing and installing lighting will become much easier and stress-free.

Commercial lighting


Photometric analysis is required for commercial areas such as parking lots and highways. Codes require compliance with minimum, maximum and average light levels. Additional planning is necessary to mitigate safety issues and avoid potential liability.

It is impossible to know which lighting technology will provide the best light. Whether a parking lot is lit by large floodlights mounted on poles, wall lights mounted on buildings, bollard lights mounted on the ground, or a combination of both, a photometric analysis can help avoid reliance on assumptions.

Common problems of photometric lighting plan

lighting-design-is-not-bright-enoughPoor lighting levels and bad distribution are some of the biggest issues in the lighting industry. Many facility managers who are looking to convert to LEDs end up buying products online without doing a proper analysis.

When buying and installing new lighting, they make assumptions about what will work in their space.

“It is not bright enough, the light is not uniform, and the light is too bright beneath the fixture” are some of the complaints we hear.

Thus, the photometric lighting plan is always suggested. There is no guarantee that you will get what you want. Even though some suppliers will say that all of the fixture are the same, we know that is not true.

If you want to accurately predict how your lights will look, you need to understand how light behaves in large spaces. Unless you are a lighting engineer, you don’t have access to this information. That is where the photometric lighting plan can be found.

A photometric lighting plan takes everything into account and does the math for you so that you can make an informed lighting purchase, even if you are a lighting engineer.

Buying lighting fixture online can be difficult because you can’t be certain of what you’re getting. Old inventory can be sold by manufacturers with outdated features. You will quickly realize that you have made a huge mistake when you see the price.


Methods of measuring light have been around for centuries, but the standardization and storage of data is just beginning. Ask lighting designers what the industry was like before IESNA started formatting luminaire data, and the answer may not be good.

It was impossible for a single design firm to produce and maintain all the data. IESNA stepped in and helped them create photometric charts. iesna has a file format for photometric data. This is not an exciting breakthrough for the general public, but it is a huge relief for designers. There are hundreds of photometric charts in the IESNA archive that lighting professionals can read with specialized software.

The introduction of the IES archive allows lighting professionals to quickly reference any fixture and figure out which fixture is best for their project. Luminaires should not be stuck in the same socket.

Photometric lighting design Questions & Answers

1. What is photometric lighting study?

A photometric plan is a study of what the lights will look like once installed. With advanced computer modeling, a model can be created that illustrates the direction, brightness and uniformity of the lights.

This model ensures that you have a plan in place before you purchase or install the lights.

2. What is dark sky compliance?

If light is kept at lower levels and away from higher levels, it can be harmful to birds and astronomy. Most regulations now require keeping the sky dark or dark sky compliance. These regulations help the environment and save energy at the same time.

3. How to interpret the photometric lighting reports?

A photometric plan has a lot of data. The average footcandle is the most important reading. Meeting your footcandle and uniformity goals is the first thing you want to do. It needs to be looked at with both horizontal and vertical fc.

The number of fixtures and their placement is the second thing to look at. If this can be done on a budget, you will need to get it right.

Flooding, lighting maintenance levels and minimum fc are some of the things to review. All of these should be reviewed by your lighting designer.

4. What is lux?

Lux is a measure of the intensity of light seen by humans. It is a unit of illuminance and emissivity derived from the International Organization for Standardization. It is the same as one liter of luminance per square meter.

5. What is lumen?

The SI unit of luminous flux is determined by photometric studies. It is a measure of light output and is a significant change from the “100 watt equivalent” used in the past. There is a bulb that has 1200 lumens. It will take a while, but we’ll get there. I want my living room light to have 1500 lumens. It will take a while, but we’ll get there. It’s the same amount of light per second that a uniform light source emits per unit solid angle of one steradian degree.

6. What is beam angle?

The angle at which light is distributed or emitted is called the beam angle. This can be achieved by designing the light in a specific way, similar to what is done with LEDs, which have a number of available beam angles.

7. What is ISOline?

ISOlines are a line joining equal parts because the word ISO originated from Greek. ISOlines allow a lighting designer to see the lighting levels on a lighting plan. These lines can be added to a drawing or lighting map to help highlight areas of too much or too little light.

8. Should I get a photometric lighting design?

For areas like parking lots, it is important to have photometric measurements. Regulations require compliance with minimum, maximum and average light levels. Additional planning will help mitigate safety issues and avoid potential liability.

It is impossible to know which lighting technology will provide the best light. If a parking lot is lit by large floodlights mounted on poles, wall sconces mounted on buildings, bollard lights mounted on the ground, or some combination, photometric analysis can help avoid relying on assumptions. With the help of photometric analysis, the lighting output can be reviewed.


Fixture photometric layout and analysis is very fast and efficient. Indoor or outdoor lighting is available for any size job. We can help you select the right fixtures for your project and place them in a way that meets the IES minimum recommendations. Most photometric analyses can be completed in a matter of days. Please don’t hesitate to drop us a message to get a free lighting design by DIALux or RELUX.

error: Content is protected !!