About the data set

Threshold versus intensity curve

The data set decribes changes in contrast sensitivity with varying background luminance. The data is reproduced from the paper: Blackwell H.R. Contrast thresholds of the human eye. J. Opt. Soc. Am. 1946;36:624-632. The data is for Part I (increments) and Part II (decrements).

In a laboratory built for the purpose of these measurements, over 400,000 observations have been recorded and manually analyzed to determine detection thresholds for circular disks of different sizes (from 0.06 to 2 deg diameter) shown on a uniform adapting field (from 10^-5 to 10^3.5 cd/m²).

Stimuli list

All stimuli shown at the detection threshold magnified x10. The visible banding (quantization) is due to 8-bit image files and display panel and is not present in the actual data.

d=121.0_logB0=3.33

mean luminance = 2160.95 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 2161.82

d=121.0_logB0=1.61

mean luminance = 40.6252 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 40.6275

d=121.0_logB0=0.06

mean luminance = 1.15846 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 1.1583

d=121.0_logB0=-0.46

mean luminance = 0.347389 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.347392

d=121.0_logB0=-2.22

mean luminance = 0.00601095 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.006009

d=121.0_logB0=-2.45

mean luminance = 0.0035308 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.00353

d=121.0_logB0=-2.76

mean luminance = 0.00173274 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.001733

d=121.0_logB0=-4.46

mean luminance = 3.46501e-05 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 3.5e-05

d=55.2_logB0=2.62

mean luminance = 415.766 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 415.738

d=55.2_logB0=1.14

mean luminance = 13.8035 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 13.7981

d=55.2_logB0=0.61

mean luminance = 4.10109 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 4.10034

d=55.2_logB0=0.03

mean luminance = 1.07385 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 1.07354

d=55.2_logB0=-1.49

mean luminance = 0.0327156 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.032721

d=55.2_logB0=-2.45

mean luminance = 0.00357861 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.003579

d=55.2_logB0=-3.46

mean luminance = 0.000346507 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.000347

d=55.2_logB0=-5.41

mean luminance = 3.86091e-06 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 4e-06

d=18.2_logB0=2.62

mean luminance = 412.98 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 412.877

d=18.2_logB0=1.62

mean luminance = 41.7591 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 41.7657

d=18.2_logB0=0.60

mean luminance = 4.02491 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 4.0255

d=18.2_logB0=-1.50

mean luminance = 0.0316782 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.031683

d=18.2_logB0=-2.42

mean luminance = 0.00382808 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.003827

d=18.2_logB0=-2.79

mean luminance = 0.00162882 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.001629

d=18.2_logB0=-4.45

mean luminance = 3.57137e-05 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 3.6e-05

d=9.7_logB0=2.59

mean luminance = 387.02 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 387.097

d=9.7_logB0=1.07

mean luminance = 11.688 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 11.6902

d=9.7_logB0=-0.46

mean luminance = 0.347389 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.347392

d=9.7_logB0=-2.22

mean luminance = 0.00599645 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.005995

d=9.7_logB0=-2.45

mean luminance = 0.00355526 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.003555

d=9.7_logB0=-3.45

mean luminance = 0.000357003 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.000357

d=9.7_logB0=-5.46

mean luminance = 3.43462e-06 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 3e-06

d=3.6_logB0=1.61

mean luminance = 40.4502 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 40.4408

d=3.6_logB0=0.61

mean luminance = 4.07084 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 4.07212

d=3.6_logB0=-1.52

mean luminance = 0.0303315 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.030326

d=3.6_logB0=-2.42

mean luminance = 0.0038361 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.003835

d=3.6_logB0=-2.81

mean luminance = 0.00156289 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 0.001563

d=3.6_logB0=-4.48

mean luminance = 3.30211e-05 cd/m²
pixels_per_degree = 120
viewing_distance = 12
surround_l = 3.3e-05