ISF Color Science & Image Fidelity 4 — Questions and Answers
Question 1: What is the viewing angle standard for critical display evaluation recommended by SMPTE and ISF?
- 30° off-axis
- Zero degrees (direct axis) (Correct answer)
- 15° below eye level at a distance of 3x screen height
- 45° from the screen surface
Correct answer: Zero degrees (direct axis)
Critical display evaluation requires measuring and viewing on-axis (0°) to avoid the color shift and luminance falloff that occur at off-axis angles.
Question 2: Which term describes the ratio of the brightest white to the darkest black a display can simultaneously reproduce?
- Dynamic range ratio
- Contrast ratio (Correct answer)
- Luminance efficiency
- Tone scale factor
Correct answer: Contrast ratio
Contrast ratio is the measurement of maximum white luminance divided by minimum black luminance measured under identical display conditions.
Question 3: In the context of display calibration, what does 'grayscale tracking' assess?
- Whether all gray values maintain the correct white point across the tonal range (Correct answer)
- The display's ability to reproduce fast motion in monochrome
- The uniformity of luminance from center to edges of the panel
- The accuracy of the display's automatic brightness sensor
Correct answer: Whether all gray values maintain the correct white point across the tonal range
Grayscale tracking verifies that the display's white point (color temperature balance) remains consistent from near-black through peak white, with no color cast at any luminance level.
Question 4: What is the function of the Electro-Optical Transfer Function (EOTF) in a display system?
- Converts the electrical video signal into the corresponding light output (Correct answer)
- Encodes camera sensor data into digital video signals
- Translates audio signals into synchronized display timing
- Regulates power consumption based on ambient light sensors
Correct answer: Converts the electrical video signal into the corresponding light output
The EOTF defines how a display converts its incoming digital signal values into emitted light luminance levels, determining the display's tone reproduction.
Question 5: Which color space encompasses the largest gamut and is used as a reference for cinema production and HDR mastering?
- sRGB
- Rec. 709
- DCI-P3
- Rec. 2020 (Correct answer)
Correct answer: Rec. 2020
Rec. 2020 (BT.2020) defines the widest standardized color gamut, covering approximately 75.8% of the CIE 1931 color space, used as the target for UHD and HDR content.
Question 6: When a display exhibits 'color decoding errors,' which control is used to correct the color saturation level in ISF calibration?
- Brightness
- Color (Chroma/Saturation) (Correct answer)
- Tint (Hue)
- Sharpness
Correct answer: Color (Chroma/Saturation)
The Color or Saturation control adjusts the amplitude of the chroma signal, correcting errors where colors appear either washed out or oversaturated.
Question 7: What is the recommended minimum ambient light level for a critical viewing environment per ISF standards?
- 0 lux (complete darkness)
- Less than 4 lux at the screen surface (Correct answer)
- Between 50 and 100 lux
- Matched to outdoor daylight conditions
Correct answer: Less than 4 lux at the screen surface
ISF recommends maintaining ambient light below 4 lux at the screen surface in a dedicated viewing room to prevent veiling glare from compromising perceived contrast.
ISF Color Science & Image Fidelity 4
What is the viewing angle standard for critical display evaluation recommended by SMPTE and ISF?