Photosensitivity in Games Quick Tips Guide

Why? To help developers in pre-production have the necessary “at-glance” aspects of game design to pay attention to with the goal of photosensitivity awareness.

Contact: LianaAccessibilityLine@gmail.com

Quick facts:

• Avoid rapid flashing, especially in high contrast environments (I.e., the most dangerous combination is white on black, red and white on black, red on black. See also pale grey)
• Avoid flashing greater than 3 Hertz
• Flashing lights should be placed in the distance from one another with flashes set at the same time to avoid accidentally recreating a harmful flash sequence above the recommended Hertz with non-synced patterns, if possible. This won’t always be possible with the creative vision. That’s OK
• Also consider transition effects, versus aggressive flash on/off.
• Fade in/Fade out, wavelength animation, etc.
• For different types of triggers and epilepsy, including photosensitive-prone, feel free to mosey over to this resource that I wrote at Game Informer as a “Epileptic’s Guide to Gaming” in conjunction with the Epilepsy Foundation of America.

Luminance flash failure

Definition: A flash is defined as a 10% change in luminance (where 100% is the maximum luminance of a white screen)

• The darker luminance value should be below 0.8.

Failure criteria:

• Flashes occur too frequently (approximately more than 3-per second).
• Flashes take up a certain amount of the screen (approximately 20% or more).
• Lower-intensity flashing can also cause a negative neurological reaction (or a Harding failure) if it’s continued for an extended period of time.

How to address:

• Reduce the contrast between the brightest and darkest parts of flashing effects.
• Reduce the frequency of the flashing.
• Decrease the size of the flashing animation.

Red flash failure

Definition: A red flash requires a lower change in luminance than a normal flash. Specifically, it applies when either extreme of the flash is a saturated red. For the tech nerds (waddup): (R/(R + G + B) >= 0.8).

• A flash here is defined when the change in the value of (R-G-B) × 320 is greater than 20.

Failure criteria:

• Flashes occur too frequently (approximately more than 3-per second).
• Flashes take up a certain amount of the screen (approximately 20% or more).
• Lower-intensity flashing can also cause a failure if it’s continued for an extended period of time.

How to address:

• Desaturate the red coloring.
• Reduce the contrast between the brightest and darkest parts of the flash.
• Reduce the frequency of the flashing.
• Decrease the size of the flashing.

Spatial pattern failure

Definition: Alternating bands that have high contrast define a spatial pattern.

Failure criteria:

• The difference in contrast is greater than 10%.
• The pattern takes up a large part of the screen (20% or more).

How to address:

• Reduce the contrast between the bands
• Decrease the size of the pattern.