Understanding Delta E: The Key to Color Accuracy in Displays

When you’re in the market for a high-quality monitor, especially if color accuracy is paramount, you’ll likely encounter the term “Delta E.” In essence, Delta E (δE) is a metric that quantifies the discrepancy between a displayed color and its intended color. A lower Delta E value signifies superior color accuracy. But what exactly does this mean, and why is it so crucial, particularly for professionals who rely on accurate visual representation?

Let’s delve deeper into the concept of Delta E and explore its significance in the world of monitors and displays. Or, if you’re already convinced of its importance and seeking top-tier color performance, explore our range of professional-grade ColorPro monitors.

In the vast landscape of consumer and professional electronics, jargon can often overwhelm and confuse consumers. We’ve previously demystified terms like lumens and resolution. However, Delta E (often represented as ΔE or E*) stands out as a particularly important, yet sometimes misunderstood, concept in the realm of display technology.

Delta E serves as a critical benchmark for evaluating color accuracy. For creative professionals such as photographers, video editors, graphic designers, and anyone involved in color-critical workflows, understanding Delta E is not just beneficial—it’s essential. It’s a key specification that distinguishes professional-grade monitors from standard displays.

While the importance of Delta E is clear for professionals, its technical nature can make its definition seem complex. Therefore, let’s break down what Delta E truly represents and how you can utilize this metric to make informed decisions when investing in visual equipment.

What Exactly is Delta E (δE)?

Delta E is a standardized measurement, established by the Commission Internationale de l’Eclairage (CIE), also known as the International Commission on Illumination. This standard mathematically quantifies the perceived color difference between two colors as rendered on a screen or display. When evaluating monitors, projectors, or any digital display, the goal is to find a device with a Delta E value as close to zero as possible.

In simpler terms, Delta E represents the magnitude of difference between the color displayed by a monitor and the original, intended color of the input signal. A lower Delta E figure indicates a smaller color difference and thus, greater color accuracy. Conversely, a high Delta E level suggests a significant color mismatch and lower accuracy.

The “E” in Delta E originates from “Empfindung,” the German word for “sensation” or “perception.” Delta (δ or Δ) is a Greek symbol denoting a change or difference in a variable. Therefore, Delta E literally translates to “difference in color sensation” or “perceived color difference.”

Delta E is measured on a numerical scale, typically ranging from 0 to 100. On this scale:

0 represents no perceivable color difference – the displayed color is identical to the reference color.
Higher values indicate increasingly larger color differences and greater color distortion.
100 would represent the maximum possible color difference, essentially colors that are completely opposite.

To provide a practical understanding of Delta E values, Zachary Schuessler’s guide (http://zschuessler.github.io/DeltaE/learn/) offers the following perception ranges:

≤ 1.0: Color difference is not perceptible to the human eye. This is considered an ideal level of color accuracy, virtually indistinguishable from perfect.
1-2: Color difference is perceptible only through close observation by trained eyes. For most users, this level of accuracy is still considered excellent and suitable for professional work.
2-10: Color difference is perceptible at a glance. This level of inaccuracy might be acceptable for general use but is generally not suitable for color-critical professional applications.
11-49: Colors are more similar than opposite, but the difference is easily noticeable. This range represents significant color distortion and is unacceptable for any application requiring color accuracy.
100: Colors are perceived as exactly opposite. This is the maximum possible color difference.

Why Delta E is Crucial for Professionals

Understanding Delta E is paramount for professionals because, as mentioned earlier, it’s the cornerstone of color accuracy. It provides an objective, quantifiable metric to assess how faithfully a display reproduces colors, eliminating reliance on subjective visual assessments.

Beyond mere aesthetics, color accuracy, as defined by Delta E, has significant implications for professional workflows. For creative professionals, low Delta E values across their monitors ensure consistency and reliability in their visual work. This is critical when:

Editing Photos and Videos: Accurate color representation is essential for making precise adjustments to color balance, grading, and retouching. Misrepresented colors due to high Delta E can lead to inaccurate edits and inconsistent results across different displays or when viewed by clients.
Graphic Design and Printing: Designers working on branding, marketing materials, or web design need to ensure that colors appear as intended across various media, from digital screens to printed materials. Low Delta E monitors help bridge the gap between digital design and final output.
Color Matching and Proofing: In industries like printing, fashion, and product design, accurate color matching is crucial. Delta E helps professionals ensure that colors are consistent throughout the production process, from initial design to final product.
Multi-Monitor Workflows: Professionals often utilize multiple monitors for increased productivity. If these monitors have varying Delta E values, color inconsistencies across screens can disrupt workflow and lead to errors. Low Delta E monitors ensure a uniform and accurate color experience across a multi-monitor setup.

In essence, investing in monitors with low Delta E values empowers professionals to perform color-critical tasks with confidence, knowing that what they see on their screen accurately reflects the true colors of their work. This translates to higher quality output, reduced rework, and improved client satisfaction.

Calculating Delta E: A Deeper Dive

Delta E, or total color difference, is calculated based on the differences in three colorimetric components: delta L*, delta a*, and delta b*. These components originate from the CIELAB color space (which we’ll discuss later) and provide a comprehensive numerical description of color within a three-dimensional, rectangular coordinate system.

Let’s break down what each component represents:

dL* (Delta L*): Represents the difference in lightness between the sample color (the displayed color) and the standard color (the intended color). A positive dL* value indicates the sample color is lighter than the standard, while a negative value indicates it’s darker.
da* (Delta a*): Represents the difference in redness or greenness between the sample and standard colors. A positive da* value indicates the sample color is redder, and a negative value indicates it’s greener. A value of 0 represents neutrality on the red-green axis.
db* (Delta b*): Represents the difference in yellowness or blueness between the sample and standard colors. A positive db* value indicates the sample color is yellower, and a negative value indicates it’s bluer. A value of 0 represents neutrality on the yellow-blue axis.

For each component (dL*, da*, db*), a higher absolute value indicates a greater difference in that specific color dimension.

The most common Delta E formula, known as CIE76, provides a straightforward calculation of the total color difference. It essentially calculates the Euclidean distance between two colors in the CIELAB color space. The formula involves squaring the differences of each component, summing them, and then taking the square root of the sum.

As shown in the image above, the CIE76 formula is:

*ΔE_ab = √((L₂ – L₁)² + (a₂ – a₁)² + (b₂ – b₁)²)**

Where:

L₁, a₁, b*₁ are the CIELAB values of the standard color.
L₂, a₂, b*₂ are the CIELAB values of the displayed color.

While CIE76 is a widely used and relatively simple formula, more advanced and perceptually uniform Delta E formulas exist, such as Delta E(94) and Delta E(2000). These newer formulas take into account the non-linearities of human color perception and provide more accurate assessments of color difference, especially for larger color differences. However, they are significantly more complex and often require specialized software or color measurement tools for calculation. For general understanding and monitor specifications, CIE76 Delta E remains a relevant and commonly cited metric.

Why Aim for a Monitor with Delta E ≤ 2

When selecting professional-grade electronics equipment, especially monitors, prioritizing devices with a Delta E value of two or less (≤ 2) is highly recommended. At this threshold, the color difference becomes virtually imperceptible to the human eye for most viewers under normal viewing conditions. This means that the displayed colors are perceived as being very close to the intended colors.

High-end, top-tier displays, often priced at a premium, can achieve even lower Delta E values, sometimes reaching Delta E ≤ 1 or even below. While achieving a Delta E of zero is theoretically impossible in real-world display manufacturing, these ultra-low values represent exceptional color accuracy, indistinguishable from perfect for practical purposes.

Monitors with Delta E ≤ 2 strike an excellent balance between color accuracy and cost-effectiveness. They provide the level of color fidelity necessary for professional creative work without necessarily requiring the absolute highest-end and most expensive technology.

How Are Colors Measured for Delta E Calculation?

A common question arising from discussions about Delta E is: how are colors measured precisely to calculate this metric? While physical attributes like weight and size can be measured with scales and rulers, light and color are more abstract. Accurate color measurement relies on specialized instruments and standardized color spaces.

For measuring the light emitted by a display, a colorimeter is the standard instrument. A colorimeter is a device that measures color intensity and chromaticity. It works by measuring light through a set of XYZ filters. These are optical filters designed to mimic the spectral sensitivities of the human eye’s photoreceptors and correspond to the tristimulus values (XYZ).

Tristimulus values (XYZ) form the foundation of colorimetry and are central to the CIE color system. The CIE color system is a set of international standards defining how colors are measured and specified. The XYZ color space is a device-independent color space, meaning it defines colors based on human perception rather than the capabilities of a specific device like a monitor or printer.

Colorimeters measure the light emitted by a display and convert it into XYZ tristimulus values. These XYZ values can then be further converted into other color spaces, such as CIELAB, which is used for Delta E calculations.

Understanding CIELAB Color Space

CIELAB, also known as CIE L*a*b* or simply Lab color space, is a color space developed by the International Commission on Illumination (CIE) in 1976. It’s designed to be perceptually uniform, meaning that equal numerical differences in CIELAB values correspond to approximately equal perceived differences in color. This perceptual uniformity is a key advantage over other color spaces like RGB or CMYK.

As briefly explained earlier, CIELAB represents color using three components:

L* (Lightness): Ranges from 0 to 100, where 0 represents perfect black (0% reflectance or transmission), 50 represents middle gray, and 100 represents perfect white (100% reflectance). It essentially defines the brightness or darkness of a color.
a* (Red-Green Axis): Represents the color’s position on the red-green spectrum. Positive a* values indicate redness, negative values indicate greenness, and 0 represents neutrality (neither red nor green).
b* (Yellow-Blue Axis): Represents the color’s position on the yellow-blue spectrum. Positive b* values indicate yellowness, negative values indicate blueness, and 0 represents neutrality (neither yellow nor blue).

Hunterlab provides a comprehensive resource on CIELAB and Delta E.

The three-dimensional nature of CIELAB allows it to represent a vast range of colors, encompassing the entire visible spectrum. Its perceptual uniformity makes it particularly well-suited for color difference measurements and applications where accurate representation of human color perception is critical.

CIELAB is a device-independent color space, meaning its color definitions are independent of how colors are created or displayed. This makes it a valuable standard for color communication across different devices and workflows. A common application is in color management workflows for converting colors between different color spaces, such as converting RGB colors (used for displays) to CMYK colors (used for printing).

Furthermore, CIELAB is copyright and license-free, residing entirely in the public domain. This open accessibility makes it a widely adopted and versatile color space across various industries and applications.

Other Important Color Spaces: RGB and HSV

While CIELAB is a cornerstone in colorimetry and Delta E calculations, other color spaces are also significant in digital graphics and display technology. RGB and HSV are two such color spaces worth understanding.

RGB (Red, Green, Blue) is an additive color model. It creates colors by combining different intensities of red, green, and blue light. RGB is the fundamental color space for displays, monitors, and screens because these devices physically produce colors using red, green, and blue light-emitting elements (pixels).

In RGB, each color component (Red, Green, Blue) is typically represented by a value ranging from 0 to 255 (in 8-bit color depth), where 0 represents the absence of that color component and 255 represents its maximum intensity. By mixing different proportions of these three primary colors, a wide spectrum of colors can be generated.

While RGB is effective for color display, it’s not always intuitive for tasks like color selection and manipulation in graphics software. This is where HSV (Hue, Saturation, Value) comes into play.

HSV is a color space that provides a more user-friendly and perceptually relevant representation of color compared to RGB. It’s often described as a cylindrical color space, defined by three components:

Hue: Represents the dominant color or wavelength (e.g., red, yellow, blue). It’s often visualized as an angle around a color wheel, typically ranging from 0° to 360°.
Saturation: Represents the color’s purity or intensity. It ranges from 0% (gray or desaturated) to 100% (fully saturated, vibrant color).
Value (or Brightness): Represents the lightness or darkness of the color. It ranges from 0% (black) to 100% (fully bright color).

HSV aligns more closely with how humans perceive color, making it easier for graphic designers and artists to select and adjust colors based on intuitive attributes like hue, saturation, and brightness, rather than manipulating the red, green, and blue components directly. Many graphics editing software suites offer HSV color pickers and adjustments alongside RGB.

The hue component in HSV is often categorized into color ranges, such as:

Red: 0° – 60°
Yellow: 61° – 120°
Green: 121° – 180°
Cyan: 181° – 240°
Blue: 241° – 300°
Magenta: 301° – 360°

While HSV is less commonly used as a display standard compared to RGB, its perceptual advantages make it a valuable tool for color manipulation and selection in digital graphics workflows.

Putting It All Together: The Importance of Low Delta E

Regardless of the color space used in your projects (CIELAB, RGB, HSV, or others), the Delta E value of your display equipment remains a critical factor for color accuracy. Choosing monitors or projectors with high Delta E values will inevitably result in viewing images and colors that deviate from their intended appearance. This can have significant consequences, especially in color-critical professional fields.

Therefore, prioritizing displays with a Delta E of less than two (≤ 2) is essential for anyone who values accurate color representation. Investing in high-quality monitors like the ViewSonic ColorPro series, which are engineered for low Delta E values, is a worthwhile investment. While these advanced displays may sometimes come at a higher initial cost compared to standard monitors with higher Delta E, the improved color accuracy and reliability they provide ultimately lead to greater satisfaction, higher quality work, and more accurate visual communication.