Image 34

original colour coded

and with an inserted data grid:

(in the middle of tiles, median of raw G-pixels values is given, the bottom value is the tile luminance divided by one candela per square meter).
# Date/Time    : 2005:08:05 01:12:45
# Resolution   : 2048 x 1536 in jpeg (2064x1540 in pgm/34.pgm)
# Focal length : 23.4mm
# Exposure time:60.120 s 
# Aperture     : f/4.0
# ISO equiv.   : 100

#c li count  min   Yav   max  ovf   min  Cav    max   ovf   min  Gav    max   ovf   min  Mav   max   ovf
# %    Y     C     G     M readings  Y        C        G        M        L / cd/m2
  1    11     0    -8    -3       1.74E-4   0.00    -1.57E-4  -6.22E-5   2.74E-4
 10    41    27    23    25       6.49E-4   4.53E-4   4.52E-4   5.19E-4   7.09E-4
 50    91    67    68    69       0.00144   0.00113   0.00134   0.00143   0.00147
 90   359   264   251   248       0.00569   0.00443   0.00493   0.00515   0.00591
 99  4260  2951  2761  2783       0.0675   0.0496   0.0542   0.0578   0.0715
100 16311 16312 16312 16304       0.258    0.274    0.320    0.338    0.240 
# flux from 0.0678 sr ( 8.61E-8 sr/4px) is  2.73E-4 lx;
# tilewise luminance  0.00368 cd/m2 with rel. SD  229 % (summing pixels below 16380)
# dark frame dark/1m.pgm subtracted from all values
# Yell average= 245.0  minimum= -512  maximum=16311   over 16380: 1285
# Cyan average= 179.9  minimum= -481  maximum=16312   over 16380: 1368
# Gree average= 175.5  minimum= -512  maximum=16312   over 16380: 1808
# Mage average= 176.7  minimum= -512  maximum=16304   over 16380: 1473

End of results of "raw2lum" (version 1.22) with parameters:
  -c YCGM -fa -w 7.3 -fc1.03 -o 16380 -d dark/1m.pgm -sm200 -nh -i 34.txt -e 34.eps -n 34.ppm -t168 -c 3412 -s64 pgm/34.pgm

Just points with luminances below 0.20 cd/m2. In grid tiles, flux densities from these points and tiles are given.
# Date/Time    : 2005:08:05 01:12:45
# Resolution   : 2048 x 1536 in jpeg (2064x1540 in pgm/34.pgm)
# Focal length : 23.4mm
# Exposure time:60.120 s 
# Aperture     : f/4.0
# ISO equiv.   : 100

#c li count  min   Yav   max  ovf   min  Cav    max   ovf   min  Gav    max   ovf   min  Mav   max   ovf
# %    Y     C     G     M readings  Y        C        G        M        L / cd/m2
  1    11     0    -8    -3       1.74E-4   0.00    -1.57E-4  -6.22E-5   2.74E-4
 10    41    27    23    25       6.49E-4   4.53E-4   4.52E-4   5.19E-4   7.09E-4
 50    91    67    68    69       0.00144   0.00113   0.00134   0.00143   0.00147
 90   359   264   251   248       0.00569   0.00443   0.00493   0.00515   0.00591
 99  4260  2951  2761  2783       0.0675   0.0496   0.0542   0.0578   0.0715
100 16311 16312 16312 16304       0.258    0.274    0.320    0.338    0.240 
# flux from 0.0677 sr ( 8.61E-8 sr/4px) is  2.56E-4 lx;
# tilewise luminance  0.00349 cd/m2 with rel. SD  214 % (points with luminances below  0.20  )
# dark frame dark/1m.pgm subtracted from all values
# Yell average= 230.3  minimum= -512  maximum=16311   out of range: 2145
# Cyan average= 169.5  minimum= -481  maximum=16312   out of range: 2228
# Gree average= 166.0  minimum= -512  maximum=16312   out of range: 2668
# Mage average= 166.7  minimum= -512  maximum=16304   out of range: 2333

End of results of "raw2lum" (version 1.22) with parameters:
  -c YCGM -ft -w 7.3 -fc1.03 -o 16380 -U0.2 -d dark/1m.pgm -sm200 -nh -i 34.txt -e 34.eps -n 34.ppm -t168 -c 3412 -s64 pgm/34.pgm

Luminance scale / 1 
cd/m<sup>2</sup>
Logarithmic luminance scale (the unit is candela per square meter) – intensities of snow illuminance in lux would be obtained by multiplying the numeric value of luminance by 3.6. For asphalt, such a coefficient is between 20 and 40 (or much less, for specular reflection of distant lamps)