[argyllcms] Re: Pre-linearization table for BtoA LUT

  • From: John Weissberg <jw@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 18 Oct 2007 16:21:40 +0200

Thanks very much for you explanation. I am sorry to be a bit thicker than the average. Since our BtoA tables are 16-bit with V2.2 profiles, I understand that the mapping below (for 8-bit profiles) is not correct:


idx    L    a    b
0    0.00    -128.00    -128.00
1    3.13    -120.03    -120.03
2    6.25    -112.06    -112.06
3    9.38    -104.09    -104.09
4    12.50    -96.13    -96.13
5    15.63    -88.16    -88.16
6    18.75    -80.19    -80.19
7    21.88    -72.22    -72.22
8    25.00    -64.25    -64.25
9    28.13    -56.28    -56.28
10    31.25    -48.31    -48.31
11    34.38    -40.34    -40.34
12    37.50    -32.38    -32.38
13    40.63    -24.41    -24.41
14    43.75    -16.44    -16.44
15    46.88    -8.47    -8.47
16    50.00    -0.50    -0.50
17    53.13    7.47    7.47
18    56.25    15.44    15.44
19    59.38    23.41    23.41
20    62.50    31.38    31.38
21    65.63    39.34    39.34
22    68.75    47.31    47.31
23    71.88    55.28    55.28
24    75.00    63.25    63.25
25    78.13    71.22    71.22
26    81.25    79.19    79.19
27    84.38    87.16    87.16
28    87.50    95.13    95.13
29    90.63    103.09    103.09
30    93.75    111.06    111.06
31    96.88    119.03    119.03
32    100.00    127.00    127.00

Would it be too much trouble to ask you what the correct mapping is for a 16-bit LUT?


--
John Weissberg
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