QTR-Quadtone RIP

I suggest you use the 21 x4 chart... measuring 256 is not going to get you a smoother curve.   The random 21x4 works well...this is what Roy suggested...

Cheers

Phil

--- In QuadtoneRIP@yahoogroups.com, "Vincent Wan" <wan@...> wrote:
>
> Dear All,
> 
> How do I figure out the ideal 256 lab values between black and white (where the paper white is density .03, L 97.63 and DMax is density 1.71 and 14.66)? 
> 
> I want to know this because Using an Epson 1430 and Eboni 100% and a black only profile on Epson Hot Press Natural I get do not get a perfectly linear lab curve after linearization no matter what I try. The irregularities in the curves are apparent both by measurement and visually with Graham Preston's circular targets. 
> 
> Paul Roark's BO curve in his Eboni1400 curve set have the same problems so I figure that its not just me.
> 
> I'd figure that I could try and edit the .quad values directly and get a better curve if I knew what the ideal densities were.
> 
> As a first step, I have printed a 256 gray target. It takes 2 pages for easy reading with a Spyder3Print spectro and wide margins). Since the Spyder3Print spectra is noisy, I sampled each patch 10 times from two separate printings of the target. The table below gives average of the 5,120 measurements and the quad ink values.
> 
> Following the groups advice, I am using QTR print.
> 
> Has anyone else fount the Spyder3Print spectra to be noisy? I find that the density values are most consistent, followed by Lab L, and Lab a and b are equally nosiest. I think that (at least for Lab L) that the very dark values are noiser than others.
> 
> I've been using 10 samples for each patch and two printings as a practical limit. From series of several hundred measurements of the calibration target and paper white I know that more samples would be better. But I just don't have the patience. I intend to chick the final results with 10 samples from three or four printings of the target.
> 
> Any advice would be welcome. 
> 
> Thank you,
> 
> Vincent
> 
> Profile:
> PRINTER=Quad1400-Eb
> CURVE_NAME=1430-eHPn-Eb_K100
> 
> GRAPH_CURVE=YES
> 
> N_OF_INKS=6
> DEFAULT_INK_LIMIT=35
> LIMIT_K=
> BOOST_K=41
> LIMIT_C=
> LIMIT_M=
> LIMIT_Y=
> LIMIT_LC=
> LIMIT_LM=
> 
> N_OF_GRAY_PARTS=1
> GRAY_INK_1=K
> GRAY_VAL_1=100
> 
> GRAY_HIGHLIGHT=10
> GRAY_SHADOW=10
> GRAY_OVERLAP=0
> GRAY_GAMMA=1
> GRAY_CURVE=
> 
> N_OF_TONER_PARTS=0
> TONER_HIGHLIGHT=10
> TONER_SHADOW=10
> TONER_GAMMA=1
> TONER_CURVE=
> N_OF_TONER_2_PARTS=0
> TONER_2_HIGHLIGHT=10
> TONER_2_SHADOW=10
> TONER_2_GAMMA=1
> TONER_2_CURVE=
> 
> N_OF_UNUSED=5
> UNUSED_INK_1=C
> UNUSED_INK_2=M
> UNUSED_INK_3=Y
> UNUSED_INK_4=LC
> UNUSED_INK_5=LM
> 
> LINEARIZE="0.03 0.05 0.08 0.12 0.17 0.22 0.27 0.33 0.40 0.46 0.53 0.60 0.66 0.73 0.79 0.86 0.93 1.00 1.06 1.12 1.16 1.21 1.27 1.32 1.39 1.44 1.49 1.54 1.58 1.63 1.69 1.72 1.73"
> 
> 
> Measured data:
> 
> quad value,100 - Lab l
> 0,2.13
> 14,2.53
> 27,2.85
> 42,3.25
> 57,3.65
> 71,4.04
> 85,4.45
> 98,4.78
> 111,5.14
> 123,5.54
> 135,5.94
> 147,6.19
> 158,6.52
> 170,6.86
> 181,7.14
> 193,7.53
> 204,7.77
> 216,8.19
> 228,8.59
> 239,8.82
> 251,9.11
> 262,9.43
> 274,9.72
> 285,10.09
> 296,10.41
> 308,10.75
> 319,11.01
> 330,11.29
> 341,11.64
> 352,11.87
> 364,12.34
> 374,12.57
> 386,12.71
> 397,13.10
> 408,13.51
> 420,13.74
> 432,14.09
> 444,14.42
> 457,14.77
> 469,14.96
> 483,15.47
> 496,15.35
> 509,15.94
> 523,16.31
> 537,16.82
> 551,17.16
> 566,17.58
> 581,17.94
> 596,18.14
> 611,18.69
> 627,19.20
> 643,19.57
> 659,19.95
> 675,20.28
> 692,20.44
> 708,21.01
> 724,21.25
> 741,21.66
> 757,22.17
> 774,22.54
> 790,23.28
> 807,23.51
> 822,23.83
> 839,24.07
> 855,24.49
> 871,24.90
> 886,25.29
> 902,25.69
> 918,26.03
> 933,26.19
> 948,26.39
> 963,26.54
> 978,27.02
> 993,27.38
> 1008,27.62
> 1023,28.12
> 1037,28.42
> 1052,29.02
> 1067,29.27
> 1082,29.58
> 1097,29.68
> 1113,30.17
> 1129,30.73
> 1145,30.70
> 1162,30.76
> 1180,31.10
> 1198,31.71
> 1216,31.90
> 1236,32.13
> 1256,32.32
> 1277,32.90
> 1298,33.10
> 1319,34.01
> 1341,34.34
> 1363,34.97
> 1385,35.12
> 1408,35.32
> 1430,35.88
> 1452,36.26
> 1474,36.68
> 1496,36.73
> 1517,37.02
> 1539,37.15
> 1560,37.66
> 1581,38.07
> 1602,37.97
> 1623,38.71
> 1644,38.45
> 1665,39.46
> 1686,39.75
> 1707,39.86
> 1729,40.27
> 1750,40.54
> 1772,41.12
> 1794,41.29
> 1815,41.60
> 1838,41.81
> 1862,41.85
> 1886,42.20
> 1910,42.54
> 1936,42.91
> 1962,43.19
> 1989,43.41
> 2017,43.84
> 2046,44.62
> 2076,45.07
> 2108,45.36
> 2140,45.66
> 2173,44.86
> 2206,45.89
> 2240,45.93
> 2274,46.01
> 2307,46.05
> 2340,47.01
> 2373,46.86
> 2404,47.36
> 2435,47.27
> 2466,47.00
> 2496,46.92
> 2526,47.52
> 2557,49.77
> 2588,49.89
> 2619,50.04
> 2652,50.27
> 2686,50.56
> 2722,51.42
> 2760,51.70
> 2799,51.64
> 2840,51.46
> 2883,52.49
> 2927,52.43
> 2971,52.86
> 3015,52.53
> 3060,52.49
> 3104,52.47
> 3147,53.09
> 3190,55.24
> 3232,55.82
> 3273,55.96
> 3314,56.11
> 3355,55.97
> 3396,56.96
> 3436,57.28
> 3478,57.22
> 3520,57.08
> 3563,57.73
> 3607,57.96
> 3652,58.09
> 3699,57.87
> 3746,57.16
> 3793,57.63
> 3842,57.93
> 3890,60.00
> 3939,60.51
> 3988,60.68
> 4037,60.87
> 4086,60.71
> 4136,61.21
> 4186,61.75
> 4238,61.79
> 4291,61.85
> 4346,62.36
> 4404,62.55
> 4465,62.66
> 4530,62.77
> 4597,62.16
> 4668,62.45
> 4740,62.89
> 4814,64.32
> 4888,64.90
> 4961,65.12
> 5033,65.29
> 5102,64.97
> 5171,65.54
> 5241,65.84
> 5315,66.10
> 5395,66.43
> 5486,66.85
> 5589,67.10
> 5707,67.11
> 5839,67.17
> 5980,67.01
> 6125,67.24
> 6267,67.83
> 6403,68.88
> 6532,69.55
> 6655,69.65
> 6772,69.96
> 6884,69.89
> 6993,70.26
> 7100,70.90
> 7207,71.04
> 7318,71.50
> 7435,71.87
> 7561,72.23
> 7701,72.37
> 7854,72.62
> 8017,72.67
> 8182,72.83
> 8344,73.19
> 8495,73.81
> 8631,74.37
> 8755,74.57
> 8874,74.82
> 8993,74.49
> 9118,74.90
> 9259,75.34
> 9419,75.81
> 9604,76.15
> 9810,76.57
> 10032,76.80
> 10264,77.09
> 10504,77.24
> 10747,77.46
> 10992,77.49
> 11240,77.84
> 11488,78.47
> 11739,78.74
> 12005,78.98
> 12298,79.21
> 12632,78.81
> 13022,79.74
> 13453,79.73
> 13899,80.70
> 14334,80.98
> 14748,81.48
> 15154,81.55
> 15573,81.87
> 16020,81.83
> 16495,81.99
> 16975,82.06
> 17432,82.52
> 17823,82.79
> 18279,83.03
> 19830,83.68
> 26869,84.92
> 
> Vincent Wan
> August 2012 PhD. Committee on the Conceptual and Historical Studies of Science, University of Chicago.		
> Once and future professor of Biology
>