Contrast, Color, And Size And Their Effects On Visual Perception And Signal Strength

Table of Contents


This is an introduction to the topic of discussion and an exploration of its potential implications. An exploration of the possibilities of this topic and the potential outcomes that could result is underway.


Visual Perception and Bottom Up Processing

Contrast and Contour with Color

Motion and size

Instance of Design

Recommendations for Design

In conclusion



Visual perception refers to the way we perceive the world through the light entering our eyes. Since the dawn of time, humans have had to learn to distinguish between signals and noise in order to be able to adapt to changing environments. Because humans can distinguish between the targeted signals and background noise, these signals are crucial to cognition. This review examines theories, concepts, and analyses the key aspects of signal processing. These concepts have profound implications when applied to user experience. It can be used to distinguish between an effective and usable interface. Examining the Boston Citgo sign is a great example of how user experience can be impacted by a good understanding of visual perception and the biology of the eye.

DiscussionVisual perception and bottom-up processing It allows us to recognize and interpret signals from the environment, and to take appropriate precautions or actions when these changes occur. Although the nervous and brain are skilled in interpreting signals, sometimes they are unclear. Signals are usually ambiguous. Knowing the strength will enable you to discriminate between noise and signals. Bottom-Up Processing. Because of its many connections with the optic nerve, the human eye is sensitive to signals. The cornea allows light to enter the eye, where it is focused onto the photoreceptors. The retina is composed of rods and cones. For high resolution and color vision, the fovea is “densely packed” with cones. The rods are located near the periphery and help in processing light and moving in different environments. One glance can be enough to process many signals in one go. The human eye is capable of detecting contrast, color and contour in one glance. This will all be explained in the sections below.

Contrast and color contrast are key factors in determining signal strength. Contrast describes the difference between a stimulus and the stimuli surrounding it. It perceives changes between the background, foreground, and background. The brain perceives the stimulus as a change in the background and foreground, just like our brains do with signals. To produce the best signal, it is important to strike a balance between maximum and threshold contrasts in design. Designing on the edge of only noticeable differences (JND), or over-designing, is not a good idea. Visual perceptions vary greatly depending on the viewers and viewing conditions.

Contour and Luminance. Contrast is most affected by Luminance. Luminance refers to the reflection or emission visible light onto a surface. Also, it is used to measure perceived brightness (although they are not always the same thing in practice). Humans are therefore more sensitive for luminance due to the greater number light-processing and processing rods in their retinas. This luminance sensitivities allows people to adapt to various light conditions and detect changes easily.

Humans have developed the ability to detect changes in the environment throughout evolution through contour enhancements or variances on luminance levels. Edges can be created when the luminance of an object changes rapidly. This creates contrast between the stimulus’ background and it. Once an object is detected as having edges, its luminance changes rapidly, and the nerves in the eyes exaggerate it. This allows the visual cortex of the brain to process the object. This allows humans to identify objects in the environment and give them meaning or value based upon their appearance.

Hue and saturation. Hues allow us to distinguish between different spectral colors on the visible spectrum. The intensity of a hue’s dominant wavelength at saturation, also known as purity, is called the hue’s saturation. The purest hue, or the most saturated, is the one that has the greatest influence on the signal’s intensity and contrast. Unsaturated hues would, however, have “contributions to many other wavelengths” and a lower level of contrast. Avoiding heavily saturated hues is a good practice. People generally enjoy higher levels of saturation, but there are downsides to using high-saturated hues.

Motion and sizeMotion. The most important function in visual perception is the detection of motion. It has an impact on luminance, contrast, depth and luminance sensitive. The nerve endings within the retina’s peripheral are responsible for processing and calculating motion. “Motion” is the result of a change in the visual environment. It can help us understand how real-world stimuli are created and guide our behavior and actions. Motion is a design concept. Overuse can lead to over-stimulation. Humans cannot block out motion. Designers must strategically and intentionally use motion and movement to communicate meaning.

Size. Signal processing requires that the stimulus size be considered along with its luminance, contour and shape. The signal’s size has a direct correlation with its stimulus size. The signal strength increases with increasing stimulus size. Other factors that can influence and complicate size, such as distance from the stimulus, angle of view, and environmental conditions, can greatly affect its size. The relationship between size and viewing distance is inverted. As distance increases, perceived size becomes smaller. The opposite is true for size and viewing angles. The stimulus size grows as the viewing angle increases.

Design CaseEven though each concept of signal processing has been described in its own section, in reality they all interact with each other. We will analyze a real-world design example, which is Boston’s Citgo signage at night.

Brightness and Contours. Drivers will be able to see the signs’ boundaries by looking at the sharp edges. This stark contrast in luminance between the dark backdrop and sign makes it more noticeable. The red triangle has strong contrast to its white background because of its sharp edges and shape. Since our brains can detect contoured edges, we are able to perceive contrast by boosting the edges of the sign along with the triangle.

The LED lights inside the sign emit intense luminance at night. This is sending a strong signal through the visual cortex. The Citgo sign is visible from the driver’s view when they travel west on Storrow Drive. This can make it dangerous for their safety. Even in bad weather, the bright lights can blind or blur the vision temporarily, making it easier to get into accidents. It is not surprising that drivers could be distracted by the Citgo sign when driving, as they are most sensitive to changes in luminance.

Hue and saturation. The Citgo LED sign features high saturation and strong luminance. Citgo’s logo features the most intense colors, which are the dominant wavelengths of visible light. Saturation should be used sparingly in interface design. Too many colors can cause fatigue and eye strain. Red is generally very visible due to the many red-sensitive fovea cones. However, in low light situations it is difficult to see. While the retina is less sensitive than the red one, the human’s eye shifts towards the blue side of a color spectrum when low illumination levels are high. This gives it the appearance that it has higher luminance values. While both blue and red hues can be found at the visible spectrum, it is not a good design choice to place them close together, especially when they are full saturated. Red hues are most likely to push into the stimulus’s foreground while blue tends to fade into the background. The close proximity of the lights to the eyes creates a quivering effect similar to motion at the periphery. Citgo signs already use motion through high contrast, flashing patterns. But the added distraction of saturated hues is only going to make it more distracting.

Size. Because the sign, which measures sixty feet tall, can be seen from most parts of Boston, it is easily visible from the skyline above all the buildings. It is visible from the westbound traffic on Storrow Drive because of its size. At night, the sign’s stark contrast with the sky and buildings around it makes it stand out more than the rest. The sign’s strong contrast makes it visible from any distance. This can make driving dangerous as high contrast can lead to fatigue and eye movement, especially when driving. LEDs that have higher levels of saturation and luminance tend to have a quicker onset time than other light sources.

Design Recommendations The Citgo sign’s strong contrast can cause dangerous driving conditions, especially for night-time drivers. The sensory system will become fatigued if there are too many strong signals. Interaction designers should strive to find the optimal contrast when designing interfaces. One option is to use split complement theory to reduce saturation in Citgo’s blue and red hues. Mixing darker colors with the existing blue and red can help to reduce their intensity. The signal strength sent to passersby will be reduced by reducing the luminance, especially nighttime. This can reduce brightness perception and lessen the glare produced by bright lights. The suggested contrast changes will result in a predictable and more controlled outcome.

Conclusion: Vision is the way humans perceive and process their environment. It involves how light enters our eyes. Designers will be better able to understand signals and noise. This knowledge will help them to influence the behavior and psychology of signal processing. Designers want predictable outcomes. This is possible by applying psychological and perceptual concepts related to signal strength, contrast and other factors. Each factor has a unique role in determining contrast and signal strength. But it’s important to know how all these concepts impact visual perception, design, and overall perception. The combination of all these factors can have a negative effect on the eye, as demonstrated by the iconic Citgo sign in Boston. A designer will become more efficient if they are able to understand the role of each factor. Designers can make design more appealing and less burdensome by understanding each factor.


Abdi, H. (1966). Signal_detection_theory[1].pdf (pp. 1-9). pp. 1-9.

Albers, J. (1975). Interaction of Color (Revised edition). Retrieved from

Anderson, B. L. (2003). The Role Of Occlusion In Perceiving Depth, Lightness, And Opacity. The Psychological Review, a journal published volumes. 110, pp. 785-801.

Aydin, T., Cadik, M., Myszkowski, K., & Seidel, H. P. (2010). Visually Important Edges. The ACM Transactions on Applied Perception published a study in its 7th volume, 4th issue, with the results of its research spanning from the first to the fifteenth page.

Brenner, E., & Van Damme, W. J. M. (1999). Perceived distances, shapes and sizes. In Vision Research (vol. 39, no. 5, pp. 975-986), it was found that…

Bullough, J. D. (2005). The detection and time of the colored signal lights. A study published in the Transportation Research Record in 1918 explored the effects of different road materials on vehicle performance. It concluded that certain materials, such as asphalt and concrete, yielded the best results in terms of speed and overall performance.

Busch, N. A., Debener, S., Kranczioch, C., Engel, A. K., & Herrmann, C. S. (2004). The effects of stimulus duration, size and eccentricity on visual gamma band response. The effects of electrical stimulation on the nervous system were recently examined in a study published in Clinical Neurophysiology. Through a series of experiments, researchers were able to determine that electrical stimulation can be used to effectively treat a number of neurological conditions. The results of the study were published in the August issue of the journal and indicated that the use of electrical stimulation can help to improve the functioning of the nervous system.

Falk, D. S., Brill, D. R., Stork, D. G., & Ruiz, M. J. (1988). The Optics of Nature, Photography, Color Vision, Holography: Seeing the Sun. The Physics Teacher journal published an article in its April 1988 issue about the importance of teaching physics through hands-on activities in the classroom. The article stressed that this approach was essential for students to develop a better understanding of the subject.

Gibson, E. J., & Walk, R. D. (1960). The “visualcliff” In a recent study published in Scientific American, researchers found that many factors can contribute to the success of a business. These include customer service, technology, marketing, and financial management. Through analyzing data from a variety of companies, the researchers found that the most important factor for success was customer service. Companies that put a high priority on customer satisfaction tended to have higher revenues, profitability, and customer retention rates than their peers. Additionally, the study found that investing in technology was also an important factor for success, with the increase in productivity, efficiency, and customer satisfaction leading to improved financial performance. Finally, the researchers found that marketing and financial management were also important in a successful business, with the ability to accurately forecast and budget, as well as to effectively reach the target market, being key to the success of any business.

Grossberg, S. (2012). The ability to recognize and interpret movement through vision. Encyclopedia of Human Behavior 2nd Edition (Vol. 92, pp. 637-651).

Helson, H., & Lansford, T. (1970). The Role Spectral energy of source and background color in the pleasantness of object colors. Applied Optics, 9(7), 1513.

Grossberg, S. (2012). The ability to perceive visual motion. Encyclopedia of Human Behavior 2nd Edition (Vol. 92, pp. 637-651).

Jacobs, D. E., Gallo, O., Cooper, E. A., Pulli, K., & Levoy, M. (2015). Simulating very bright and very dim scenes. The ACM Transactions on Graphics journal published an issue in its 34th volume, containing three articles.

Kim, M. H., Ritschel, T., & Kautz, J. (2011). Edge-aware color appearance. The ACM Transactions on Graphics featured an edition of 30(2) in its publication.

Majumder, A., & Irani, S. (2006). Contrast enhancement using human contrast sensitivity. The Symposium on Applied Perception in Graphics and Visualization, held in 2006, published its proceedings in a volume of one, with articles numbered from 69 to 76.

Meyer, B., Grogorick, S., Vollrath, M., & Magnor, M. (2016). Simulating visual comparison reduction in nighttime-glare situations with conventional displays. The ACM Transactions on Applied Perception published a journal article detailing the results of a study conducted on the topic, with the findings being disseminated in a fourteen-part series. The first part of the series was published in issue number one and included twenty separate pages of information.

Owsley, C. (2003). Contrast sensitivities. Ophthalmology Clinics of North America. 16, pp. 171-177.

Pal, R., Mukherjee, J., & Mitra, P. (2012). What does warm color affect our visual attention? Proceedings from ACM International Conferences.

Grossberg, S. (2012). The ability to interpret and recognize visual motion. Encyclopedia of Human Behavior 2nd Edition (Vol. 92, pp. 637-651).

Hubel, S. D., & Livingstone, M. S. (1988). Segregation: anatomy and physiology. Science, 240(4853), 740-749.

You, J., Ebrahimi, T., & Perkis, A. (2011). Video quality assessment: Modeling motion vision perception. MM’11 – Proceedings from the 2011 ACM Multimedia Conference & Co-located Workshops, 1293-1296.