IRE: What Is It In The Measurement Of Composite Video Signals?

I love creating free content full of tips for my readers, you. I don't accept paid sponsorships, my opinion is my own, but if you find my recommendations helpful and you end up buying something you like through one of my links, I could earn a commission at no extra cost to you.

Intereventrectangularity (IRE) is a measure of the relative brightness of the video signal, which is used for composite video.

It is measured in units called IREs, which is a scale of 0-100, with 0 being the darkest and 100 being the brightest.

IRE has been widely adopted by many broadcasters and video engineers as a way of measuring and calibrating the brightness of a video signal.

In this article, we will discuss what IRE is and how it is used in the measurement of composite video signals.

Definition of IRE

IRE stands for “Institute of Radio Engineers.” It is a scaling used in measuring composite video signals, usually expressed as a percentage of the reference “black” level and the peak white level (in American systems) or the reference white and peak black levels (in European and other standards). The value is traditionally shown in IRE units on an oscilloscope, using measurements that range from 0 IRE (black) to 100 IRE (white).

The term IRE was derived from an engineer at RCA in the 1920s and became standardized among television engineers for calibrating video signals. It has since been adopted by several international standards organizations, becoming an accepted measure for both TV line scan rate and modulation depth. Since each manufacturer calibrates their equipment differently, when working across multiple systems it is important to understand these different values and adjust them accordingly to ensure proper operation.


History of IRE

IRE (pronounced ‘eye-rayhee’) stands for Institution of Radio Engineers and was founded in 1912 as a professional society for radio engineers. The IRE implemented a standard for composite video signals involving the measurement of black and white definitions in electrical signal that are presented to an image display device.

IRE has been used to measure different types of video signals, such as; NTSC, PAL, SECAM, HDMI and DVI. NTSC uses a different definition of IRE than other systems, using 7.5 IRE for black level instead of 0 IRE used by most other standards making it difficult to compare the two systems.

PAL uses 0 IRE for black level and 100 IRE for white level which allows it to be compared easily with other color systems like NTSC and SECAM. High definition signals such as HDMI and DVI use an even higher definition with deep colors such as 16-235 or 16-240 being defined by the HDMI 2.0a standards where the full range is 230 or 240 values respectively following 16 which defines black while 256 defines white level correspondingly.

The modern trend is transitioning towards digital formats like HDMI which holds up better with circuit noise but still requires appropriate calibration since even digital formats require accurate synchronization between input signals like DVD players, Blu-ray players or game consoles that may have different interpretation compared to each other regarding output signals produced in relation to changes made on them from end user perspective such as brightness or contrast on television set itself.

What Is IRE?

IRE (Institute of Radio Engineers) is an abbreviation commonly used when discussing composite video signals. It is a unit of measurement used to determine the contrast, color, and brightness of a video signal, as well as sound levels. IRE is also used to determine composite video formats and measurements in the analog domain. Let’s take a closer look at IRE and its various applications.

How Is IRE Used in Video Signals?

IRE, or Inverse Relative Exposure, is a unit of measurement used to represent the amplitude of a video signal. IRE is most often used in television production and broadcast radio transmission when measuring composite video signals. It is typically measured in a range from 0 to 100 on the scale.

The IRE measurement system is based on how the eye perceives brightness and color—similar to the color temperature society generally uses for descriptions of white light. In video signals, 0 IRE indicates no video signal voltage and 100 IRE indicates maximum possible voltage (basically, an all-white image).

When measuring brightness levels, electronics manufacturers use various scale systems such as nits for LED backlit television displays or foot-lamberts for normal reflectors like movie theaters. However, these scales are based on candelas per square meter (cd/m²). Instead of using cd/m² as the linear power value of luminance information, analog signals typically use IRE as its unit for linear voltage increments in order to meet standard NTSC or PAL gain requirements.

IRE values are commonly used in the broadcast industry; broadcast engineers rely on them when calibrating equipment that captures or broadcasts composite video signals such as cameras and TVs. Generally speaking, broadcast engineers use numbers between 0-100 when adjusting/adjusting audio and video levels during filming and broadcasting.

How Is IRE Measured?

IRE stands for the Institute of Radio Engineers and is the unit of measure used when measuring composite video signals. It is measured in millivolts (mV) from 0 mV to 100 mV, signifying a normal range in which composite video signals should fall for proper operation.

The IRE goes from -40 up to 120 within each video frame and that entire range is divided into segments by reference points called IRE points. These signals are then measured from 0 IRE (black) to 100 IRE (white).

0 IRE is the exact value for true black and it corresponds to about 7.5 mV peak-to-peak amplitude on a standard NTSC signal or with 1 V peak-to-peak amplitude on PAL signal.

100IRE represents 100% white level, which is equal to a signal voltage of 70 mV peak-to-peak on an NTSC signal and 1 Volt peak-to-peak on a PAL signal; while 40 IRE below black level (-40IRE) at 300 mV peak-to-peak on NTSC signal or 4 Vand 50% gray corresponds to 35IRE (35% digital full scale).

These levels are used as reference points when measuring the various levels within the picture, such as the overall brightness or picture contrast controllers, luma or chroma gains or levels and other settings such as pedestal levels where applicable.

Types of IRE

The IRE measurement is used to gauge the amplitude level of an analog composite video signal. It stands for “instantaneous reference electrode” and is used mainly in the broadcast television industry. When it comes to IRE, there are several types that signal can be classified into, ranging from the standard IRE units to NTSC and PAL IRE units. In this article, we’ll look at the different types of IRE measurements and the differences between them.

Getting started with your own stop motion storyboards

Subscribe to our newsletter and get your free download with three storyboards. Get started with bringing your stories alive!

We'll only use your email address for our newsletter and respect your privacy


IRE (pronounced “eye-reel”) stands for Institute of Radio Engineers, which is a unit of measure used to evaluate the level of the video signal. IRE is used when measuring composite video signals.
The IRE scale is numbered from 0 to 100 and each number represents an amount of volts. An IRE 0 reading represents no relative voltage at all while an IRE 100 reading would represent 1 volt or a 100 percent luminance level relative to the blanking level. Furthermore, a 65 IRE value is equal to 735 millivolts (mV) or zero decibels referenced to one volt peak-to-peak (dBV).

The three main types of IRE include:
-IRE 0: Representing no relative voltage, this type of measurement can be used to calculate overscan and underscan in scanned images.
-IRE 15: Representing about 25 millivolts (mV), it is primarily used to measure back porch clipping and setup levels in broadcast signals.
-IRE 7.5/75%: Representing an average AGC (Automatic Gain Control) level; this type of measurement indicates the brightness range between shadowed portions inside a frame and highlighted portions outside the frame.

IRE 7.5

IRE (Institute of Radio Engineers) is the unit of measurement used to measure composite video signals in broadcast television. The IRE measurement scale ranges from 0 to 100, with the sync level being 7.5 IRE. This presents 7.5 IRE as a “black reference” that represents full black for video, which moreover defines the complete signal range in video standards such as NTSC and PAL.

In NTSC and PAL composite video signal specifications, ‘black/blacker than black’ is 0-7.5 IRE, ‘below sync’ is -40 IRE, 30 for ‘white’ and ‘brighter than white’ is 70-100 IRE respectively marking full white for this particular standard. Significant to note here is that the values between 0-7.5IRE are non-visible but tend to aid in providing accurate synchronization or timing information used by various components of televisions while receiving/transmitting TV signals; while values outside the range 0-100 MAY also appear but should be avoided if possible as they may cause adverse effects on display/performance quality of broadcast television.
Picture contrast using different shades that reside within those levels help enhance image details significantly showing it in extremely high definition on large screen TVs which would otherwise be difficult to see properly using other analog methods like S-Video or RF wired antenna systems.

IRE 15

IRE 15, also known as blanking level, is one of the signal measurement units used in composite video. A composite video signal includes horizontal and vertical sync pulses and luminance and chrominance data signals. IRE (Institute of Radio Engineers) is the standard unit used to measure the amplitude of these signals. IRE 15 corresponds to a voltage output of 0.3 volts peak-to-peak in a NTSC signal or 0 volts peak-to-peak in a PAL signal (NTSC and PAL are digital broadcasting standards).

IRE 15 is used to indicate when a part of the picture has no data – this area is known as the “blanking area”. It is located between the total black level and total white level – usually 7.5 IRE below total blanking set at 100 IRE. The range from 0 IRE (total black) to 7.5 IRE determines how dark an image appears on screen, which indicates its ability to reveal shadow detail or artistic expression within various lights and hues.

When calibrating video signals, it’s important to maintain 7.5 V peak-to-peak across all portions of the picture at all times for all sources you intend to display – this will ensure correct colorimetry within your system for both standard definition analog content as well as HDTV based formats such as ATSC, 1080p/24 etc.. When properly calibrated with 100% whites (IRE 100) at a brightness setting that won’t irritate eyes when viewing normal scenes on TV shows or movies, naturally all shadows can be seen but not overly brightened until they become virtually invisible along with several levels of blacks that would normally appear very easily distinguishable yet aesthetically appealing – This is why accessing proper settings (IRE levels) via modern electronic instruments has become so critical for making sure you get quality accurate pictures out of your home theater / live broadcast cinema setup today!

Benefits of IRE

IRE (IEEE Standards Association Radiometric Equivalent) is a unit of measurement used to measure composite video signals. This is the most commonly used unit of measurement in professional video equipment. IRE has many benefits, including the ability to accurately measure luminance and chrominance signals, which helps to create high-quality visuals. In this article, we will explore the benefits of IRE and why it is so important in the video industry.

Accurate Color Reproduction

IRE stands for institute of capacity engineers and was developed in 1938. IRE is a unit of measurement used to measure the amplitude of a composite video signal. In measuring the composite video signal, IRE provides several benefits, including accurate color reproduction.

IRE allows professional installers or technicians to ensure that colors are accurately reproduced through a video monitor when calibrating a video system. The IRE unit is able to measure not only the number of lines between black and white present on the picture, but also their relative luminance. With such precision, it is easy for an installer or technician to make sure the proper colors appear in the final image display.

IRE allows us to set up compatible equipment so that it can achieve accurate color reproduction regardless of what type of equipment is used. This ensures that color shades seen in different equipment will remain consistent across all channels and output devices involved in generating pictures or video signals. Properly calibrated monitors or displays can play a major role in ensuring that there are no discrepancies between tones or shades on separate devices during playback, ultimately giving us vivid and visually appealing images with believable hues and tones that match our original content source accurately.

Accurate Brightness Control

Integrated Rise and Fall (IRE) is a measurement that assesses the brightness of composite video signals. This standard, developed by the American National Television System Committee (ANSTC), provides a reliable measure of signal intensity which can be applied across all types of video equipment and allows for accurate brightness control.

IRE units are expressed in percentage points measured on a scale from 0 to 100. The IRE scale is further broken down into 28 values ranging from 0 IRE, which indicates total blackness, to 100 IRE, which represents peak white. Picture depth, or contrast ratio, is often measured in an IRE range of 70-100% while picture brightness or luminance is measured within an IRE range of 7-10%.

By using standard definitions and measurements such as IRE units across all types of video equipment manufacturers and technicians can accurately define the desired level of signal output for specific applications such as broadcast television which requires precise control over both the dive strength and signal rise time. Additionally technicians can confidently determine if any given piece of equipment is producing signal levels that are within established standards for safe use with other components in the signal processing chain.

Improved Picture Quality

Integrated report-expansion (IRE) technology is used in imaging systems to improve image quality. It allows healthcare professionals to see small or subtle features on MRI images that may not have been visible using other imaging techniques. The IRE process works by increasing the contrast of the displayed image, making it look sharper and clearer than before. This makes smaller lesions and tissue structures easier to identify and interpret on the screen.

IRE can also be used with ultrasound imaging, which helps physicians diagnose diseases related to the fetus and newborn babies, allowing them to detect early structural issues or genetic diseases during pregnancy. IRE can also be used with x-ray imaging which allows physicians to identify bone fractures or joint abnormalities, enabling them to provide an accurate diagnosis quickly and accurately.

URE is also currently being adopted in radiotherapy areas such as radiation oncology for more precise targeting of tumors during radiation therapy treatments, resulting in more targeted doses of radiation for greater effectiveness for patients undergoing cancer treatment. The benefits of using IRE technology are numerous; it improves patient safety by providing physicians with higher levels of accuracy when diagnosing conditions, enabling them to detect small lesions or tissues structures they might otherwise have missed without IRE’s help.


In conclusion, IRE or the Institute of Radio Engineers is a unit of measurement used to measure video signals. A 100-IRE signal is the maximum level of power possible in any given video signal, while a 0-IRE signal is equal to zero volts and the lowest possible level that a composite video signal can achieve. The IRE scale can be used to measure the strength and clarity of any given image or audio signal, whether it is being broadcasted, displayed on a television or broadcast over the Internet. Video signals are typically measured in increments of 1/100th of an IRE starting at 0 and ending at 100.

When recording audio or video, it’s typically best to record as close to 0-IRE as possible for optimal sound quality. Adjusting levels during playback, such as increasing volume or adjusting contrast and brightness can then be done without having to worry about distortion from interference. Furthermore, this system helps ensure that all systems processing composite signals have consistent calibrations for accurate measurements and scaling between systems.

Hi, I'm Kim, a mom and a stop-motion enthusiast with a background in media creation and web development. I've got a huge passion for drawing and animation, and now I'm diving headfirst into the stop-motion world. With my blog, I'm sharing my learnings with you guys.