Image 34

original lighter 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    : 2006:06:29 02:54:45
# Resolution   : 1280 x 960 in jpeg (1424x1076 in pgm/34.pgm)
# Focal length :  5.7mm  (35mm equivalent: 39mm)
# CCD width    : 5.32mm
# Exposure time: 0.500 s  (1/2)
# Aperture     : f/2.8
# ISO equiv.   : 200

# Selected image percentils         L=(1.730*0.35*R+1.000*0.65*G+1.570*0.00*B)* 6.64E-4
# %    R     G1    G2    B readings  R        G        B        L / cd/m2
  1   -50   -47   -47   -51        -0.0575  -0.0312  -0.0532  -0.0404
 10   -18   -15   -16   -21        -0.0207  -0.0103  -0.0219  -0.0139
 50    20    21    21    10         0.0230   0.0140   0.0104   0.0171
 90   209   204   204    84         0.240    0.136    0.0876   0.172 
 99  2566  2395  2384   677         2.95     1.59     0.706    2.06  
100 16155 16152 16152 16114         18.6     10.7     16.8     13.5  
# flux from 0.652*0.76 sr ( 8.59E-7 sr/4px) is  0.0656 lx ( 0.0727 lx tilewise);
# tilewise luminance  0.106 cd/m2 with rel. SD  253 % (summing pixels below 15850 and with non-zero green: there is 76.5 % of them)
# Fuji Devignetting: 1 # dark frame dark/42.pgm subtracted from all values
# Red  average= 168.9  minimum= -130  maximum=16155   over 15850: 1998 zero: 22.7 %
# GrUp average= 162.6  minimum= -128  maximum=16152   over 15850: 1925 zero: 23.6 %
# GrDw average= 162.0  minimum= -115  maximum=16152   over 15850: 1914 zero: 23.4 %
# Blue average=  74.7  minimum= -120  maximum=16114   over 15850: 767 zero: 29.6 %

End of results of "raw2lum" (version 1.22) with parameters:
  -c fuji -fa -d dark/42.pgm -sm100 -nh -nt -i 34.txt -e 34.eps -n 34.ppm -t 118 -s71:76 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)