TikZ Chromaticity Diagram

Question

I'm trying to make a chromaticity diagram in tikZ, does anyone know how to make one?

I want this

My issue is not in forming the spectral locus that I can do, right now I'm only using three points but I'm trying to color the diagram in. Does any one have any pointers or have they done this before?

Also, yes I know chromaticity diagrams should never be colored in beacsue our displays can't produce the full diagram, and etc. So color science 101 aside.

Matlab code to make the shape of the locus

 cie.lambda = [380:5:780];

%load CIE color matching data
cie.cmf2deg =    1.0e+02 * [3.800000000000000   0.000013680000000   0.000000390000000   0.000064500000000;
   3.850000000000000   0.000022360000000   0.000000640000000   0.000105500000000;
   3.900000000000000   0.000042430000000   0.000001200000000   0.000200500000000;
   3.950000000000000   0.000076500000000   0.000002170000000   0.000362100000000;
   4.000000000000000   0.000143100000000   0.000003960000000   0.000678500000000;
   4.050000000000000   0.000231900000000   0.000006400000000   0.001102000000000;
   4.100000000000000   0.000435100000000   0.000012100000000   0.002074000000000;
   4.150000000000000   0.000776300000000   0.000021800000000   0.003713000000000;
   4.200000000000000   0.001343800000000   0.000040000000000   0.006456000000000;
   4.250000000000000   0.002147700000000   0.000073000000000   0.010390500000000;
   4.300000000000000   0.002839000000000   0.000116000000000   0.013856000000000;
   4.350000000000000   0.003285000000000   0.000168400000000   0.016229600000000;
   4.400000000000000   0.003482800000000   0.000230000000000   0.017470600000000;
   4.450000000000000   0.003480600000000   0.000298000000000   0.017826000000000;
   4.500000000000000   0.003362000000000   0.000380000000000   0.017721100000000;
   4.550000000000000   0.003187000000000   0.000480000000000   0.017441000000000;
   4.600000000000000   0.002908000000000   0.000600000000000   0.016692000000000;
   4.650000000000000   0.002511000000000   0.000739000000000   0.015281000000000;
   4.700000000000000   0.001953600000000   0.000909800000000   0.012876400000000;
   4.750000000000000   0.001421000000000   0.001126000000000   0.010419000000000;
   4.800000000000000   0.000956400000000   0.001390200000000   0.008129500000000;
   4.850000000000000   0.000579500000000   0.001693000000000   0.006162000000000;
   4.900000000000000   0.000320100000000   0.002080200000000   0.004651800000000;
   4.950000000000000   0.000147000000000   0.002586000000000   0.003533000000000;
   5.000000000000000   0.000049000000000   0.003230000000000   0.002720000000000;
   5.050000000000000   0.000024000000000   0.004073000000000   0.002123000000000;
   5.100000000000000   0.000093000000000   0.005030000000000   0.001582000000000;
   5.150000000000000   0.000291000000000   0.006082000000000   0.001117000000000;
   5.200000000000000   0.000632700000000   0.007100000000000   0.000782500000000;
   5.250000000000000   0.001096000000000   0.007932000000000   0.000572500000000;
   5.300000000000000   0.001655000000000   0.008620000000000   0.000421600000000;
   5.350000000000000   0.002257500000000   0.009148500000000   0.000298400000000;
   5.400000000000000   0.002904000000000   0.009540000000000   0.000203000000000;
   5.450000000000000   0.003597000000000   0.009803000000000   0.000134000000000;
   5.500000000000000   0.004334500000000   0.009949500000000   0.000087500000000;
   5.550000000000000   0.005120500000000   0.010000000000000   0.000057500000000;
   5.600000000000000   0.005945000000000   0.009950000000000   0.000039000000000;
   5.650000000000000   0.006784000000000   0.009786000000000   0.000027500000000;
   5.700000000000000   0.007621000000000   0.009520000000000   0.000021000000000;
   5.750000000000000   0.008425000000000   0.009154000000000   0.000018000000000;
   5.800000000000000   0.009163000000000   0.008700000000000   0.000016500000000;
   5.850000000000000   0.009786000000000   0.008163000000000   0.000014000000000;
   5.900000000000000   0.010263000000000   0.007570000000000   0.000011000000000;
   5.950000000000000   0.010567000000000   0.006949000000000   0.000010000000000;
   6.000000000000000   0.010622000000000   0.006310000000000   0.000008000000000;
   6.050000000000000   0.010456000000000   0.005668000000000   0.000006000000000;
   6.100000000000000   0.010026000000000   0.005030000000000   0.000003400000000;
   6.150000000000000   0.009384000000000   0.004412000000000   0.000002400000000;
   6.200000000000000   0.008544500000000   0.003810000000000   0.000001900000000;
   6.250000000000000   0.007514000000000   0.003210000000000   0.000001000000000;
   6.300000000000000   0.006424000000000   0.002650000000000   0.000000500000000;
   6.350000000000000   0.005419000000000   0.002170000000000   0.000000300000000;
   6.400000000000000   0.004479000000000   0.001750000000000   0.000000200000000;
   6.450000000000000   0.003608000000000   0.001382000000000   0.000000100000000;
   6.500000000000000   0.002835000000000   0.001070000000000                   0;
   6.550000000000000   0.002187000000000   0.000816000000000                   0;
   6.600000000000000   0.001649000000000   0.000610000000000                   0;
   6.650000000000000   0.001212000000000   0.000445800000000                   0;
   6.700000000000000   0.000874000000000   0.000320000000000                   0;
   6.750000000000000   0.000636000000000   0.000232000000000                   0;
   6.800000000000000   0.000467700000000   0.000170000000000                   0;
   6.850000000000000   0.000329000000000   0.000119200000000                   0;
   6.900000000000000   0.000227000000000   0.000082100000000                   0;
   6.950000000000000   0.000158400000000   0.000057230000000                   0;
   7.000000000000000   0.000113590000000   0.000041020000000                   0;
   7.050000000000000   0.000081110000000   0.000029290000000                   0;
   7.100000000000000   0.000057900000000   0.000020910000000                   0;
   7.150000000000000   0.000041090000000   0.000014840000000                   0;
   7.200000000000000   0.000028990000000   0.000010470000000                   0;
   7.250000000000000   0.000020490000000   0.000007400000000                   0;
   7.300000000000000   0.000014400000000   0.000005200000000                   0;
   7.350000000000000   0.000010000000000   0.000003610000000                   0;
   7.400000000000000   0.000006900000000   0.000002490000000                   0;
   7.450000000000000   0.000004760000000   0.000001720000000                   0;
   7.500000000000000   0.000003320000000   0.000001200000000                   0;
   7.550000000000000   0.000002350000000   0.000000850000000                   0;
   7.600000000000000   0.000001660000000   0.000000600000000                   0;
   7.650000000000000   0.000001170000000   0.000000420000000                   0;
   7.700000000000000   0.000000830000000   0.000000300000000                   0;
   7.750000000000000   0.000000590000000   0.000000210000000                   0;
   7.800000000000000   0.000000420000000   0.000000150000000                   0;];
cie.illE = ones(length(cie.lambda),1); %equal energy illuminant


%Interpolate data to specifed range
interpMethod = 'linear';
cie.cmf2deg = interp1(cie.cmf2deg(:,1),cie.cmf2deg(:,2:end),cie.lambda(:),interpMethod);



cie.cmf2deg=cie.cmf2deg';
locus = [cie.cmf2deg(1,:)./sum(cie.cmf2deg);cie.cmf2deg(2,:)./sum(cie.cmf2deg)];
plot(locus(1,[1:81,1]),locus(2,[1:81,1]), 'b-'); 

v = locus(1,[1:81,1]);
g = locus(2,[1:81,1]);
for ii = 1:81
    fprintf('(%f,%f)',v(ii)*10,g(ii)*10)
    fprintf('--')
    if mod(ii,10) == 0
        fprintf('\n')
    end
end

If you copy and paste from Matlab you get this

\documentclass[]{article}
\usepackage{tikz}

\usetikzlibrary{fadings}
\usepackage[latin1]{inputenc}

\author{}
\date{}
\title{}

\begin{document}

\begin{tikzpicture}
    \draw [<->,ultra thick] (0,10) -- (0,0) -- (10,0);
    \draw [help lines] (0,0) grid (10,10);
    \draw [thick] (1.741123,0.049637)--(1.740078,0.049805)--(1.738008,0.049154)--(1.735599,0.049232)--(1.733369,0.047967)--(1.730210,0.047751)--(1.725766,0.047993)--(1.720866,0.048325)--(1.714074,0.051022)--(1.703010,0.057885)--
(1.688775,0.069002)--(1.668953,0.085556)--(1.644118,0.108576)--(1.611046,0.137934)--(1.566409,0.177048)--(1.509854,0.227402)--(1.439604,0.297030)--(1.355027,0.398791)--(1.241185,0.578025)--(1.095943,0.868425)--
(0.912935,1.327021)--(0.687059,2.007232)--(0.453907,2.949760)--(0.234599,4.127035)--(0.081680,5.384231)--(0.038585,6.548232)--(0.138702,7.501864)--(0.388518,8.120160)--(0.743024,8.338031)--(1.141607,8.262070)--
(1.547221,8.058635)--(1.928762,7.816291)--(2.296197,7.543291)--(2.657751,7.243239)--(3.016039,6.923077)--(3.373633,6.588483)--(3.731015,6.244509)--(4.087363,5.896069)--(4.440625,5.547139)--(4.787748,5.202023)--
(5.124864,4.865908)--(5.447865,4.544341)--(5.751513,4.242322)--(6.029328,3.964966)--(6.270366,3.724911)--(6.482331,3.513949)--(6.657636,3.340107)--(6.800788,3.197472)--(6.915040,3.083422)--(7.006061,2.993007)--
(7.079178,2.920271)--(7.140316,2.859289)--(7.190329,2.809350)--(7.230316,2.769484)--(7.259923,2.740077)--(7.282717,2.717283)--(7.299690,2.700310)--(7.310894,2.689106)--(7.319933,2.680067)--(7.327189,2.672811)--
(7.334170,2.665830)--(7.340473,2.659527)--(7.343902,2.656098)--(7.345917,2.654083)--(7.346873,2.653127)--(7.346920,2.653080)--(7.346783,2.653217)--(7.346683,2.653317)--(7.346680,2.653320)--(7.346719,2.653281)--
(7.346939,2.653061)--(7.347539,2.652461)--(7.348243,2.651757)--(7.345679,2.654321)--(7.345133,2.654867)--(7.343750,2.656250)--(7.345133,2.654867)--(7.358491,2.641509)--(7.345133,2.654867)--(7.375000,2.625000)--
(7.368421,2.631579)--cycle;
\end{tikzpicture}

\end{document}

Here is what I get when it try to use code to color it

\documentclass[]{article}
\usepackage{tikz}

\usetikzlibrary{fadings}
\usepackage[latin1]{inputenc}

\author{}
\date{}
\title{}

\begin{document}
\begin{tikzpicture}
\draw [<->,ultra thick] (0,10) -- (0,0) -- (10,0);
\draw [help lines] (0,0) grid (10,10);
\fill [blue] (1.741123,0.049637)--(1.740078,0.049805)--(1.738008,0.049154)--

(1.735599,0.049232)--(1.733369,0.047967)--(1.730210,0.047751)--(1.725766,0.047993)--(1.720866,0.048325)--(1.714074,0.051022)--(1.703010,0.057885)--
(1.688775,0.069002)--(1.668953,0.085556)--(1.644118,0.108576)--(1.611046,0.137934)--(1.566409,0.177048)--(1.509854,0.227402)--(1.439604,0.297030)--(1.355027,0.398791)--(1.241185,0.578025)--(1.095943,0.868425)--
(0.912935,1.327021)--(0.687059,2.007232)--(0.453907,2.949760)--(0.234599,4.127035)--(0.081680,5.384231)--(0.038585,6.548232)--(0.138702,7.501864)--(0.388518,8.120160)--(0.743024,8.338031)--(1.141607,8.262070)--
(1.547221,8.058635)--(1.928762,7.816291)--(2.296197,7.543291)--(2.657751,7.243239)--(3.016039,6.923077)--(3.373633,6.588483)--(3.731015,6.244509)--(4.087363,5.896069)--(4.440625,5.547139)--(4.787748,5.202023)--
(5.124864,4.865908)--(5.447865,4.544341)--(5.751513,4.242322)--(6.029328,3.964966)--(6.270366,3.724911)--(6.482331,3.513949)--(6.657636,3.340107)--(6.800788,3.197472)--(6.915040,3.083422)--(7.006061,2.993007)--
(7.079178,2.920271)--(7.140316,2.859289)--(7.190329,2.809350)--(7.230316,2.769484)--(7.259923,2.740077)--(7.282717,2.717283)--(7.299690,2.700310)--(7.310894,2.689106)--(7.319933,2.680067)--(7.327189,2.672811)--
(7.334170,2.665830)--(7.340473,2.659527)--(7.343902,2.656098)--(7.345917,2.654083)--(7.346873,2.653127)--(7.346920,2.653080)--(7.346783,2.653217)--(7.346683,2.653317)--(7.346680,2.653320)--(7.346719,2.653281)--
(7.346939,2.653061)--(7.347539,2.652461)--(7.348243,2.651757)--(7.345679,2.654321)--(7.345133,2.654867)--(7.343750,2.656250)--(7.345133,2.654867)--(7.358491,2.641509)--(7.345133,2.654867)--(7.375000,2.625000)--
(7.368421,2.631579)--cycle;
    \fill [red, path fading =west] (1.741123,0.049637)--(1.740078,0.049805)--(1.738008,0.049154)--(1.735599,0.049232)--(1.733369,0.047967)--(1.730210,0.047751)--(1.725766,0.047993)--(1.720866,0.048325)--(1.714074,0.051022)--(1.703010,0.057885)--
(1.688775,0.069002)--(1.668953,0.085556)--(1.644118,0.108576)--(1.611046,0.137934)--(1.566409,0.177048)--(1.509854,0.227402)--(1.439604,0.297030)--(1.355027,0.398791)--(1.241185,0.578025)--(1.095943,0.868425)--
(0.912935,1.327021)--(0.687059,2.007232)--(0.453907,2.949760)--(0.234599,4.127035)--(0.081680,5.384231)--(0.038585,6.548232)--(0.138702,7.501864)--(0.388518,8.120160)--(0.743024,8.338031)--(1.141607,8.262070)--
(1.547221,8.058635)--(1.928762,7.816291)--(2.296197,7.543291)--(2.657751,7.243239)--(3.016039,6.923077)--(3.373633,6.588483)--(3.731015,6.244509)--(4.087363,5.896069)--(4.440625,5.547139)--(4.787748,5.202023)--
(5.124864,4.865908)--(5.447865,4.544341)--(5.751513,4.242322)--(6.029328,3.964966)--(6.270366,3.724911)--(6.482331,3.513949)--(6.657636,3.340107)--(6.800788,3.197472)--(6.915040,3.083422)--(7.006061,2.993007)--
(7.079178,2.920271)--(7.140316,2.859289)--(7.190329,2.809350)--(7.230316,2.769484)--(7.259923,2.740077)--(7.282717,2.717283)--(7.299690,2.700310)--(7.310894,2.689106)--(7.319933,2.680067)--(7.327189,2.672811)--
(7.334170,2.665830)--(7.340473,2.659527)--(7.343902,2.656098)--(7.345917,2.654083)--(7.346873,2.653127)--(7.346920,2.653080)--(7.346783,2.653217)--(7.346683,2.653317)--(7.346680,2.653320)--(7.346719,2.653281)--
(7.346939,2.653061)--(7.347539,2.652461)--(7.348243,2.651757)--(7.345679,2.654321)--(7.345133,2.654867)--(7.343750,2.656250)--(7.345133,2.654867)--(7.358491,2.641509)--(7.345133,2.654867)--(7.375000,2.625000)--
(7.368421,2.631579)--cycle;
    \fill [green,path fading =south] (1.741123,0.049637)--(1.740078,0.049805)--(1.738008,0.049154)--(1.735599,0.049232)--(1.733369,0.047967)--(1.730210,0.047751)--(1.725766,0.047993)--(1.720866,0.048325)--(1.714074,0.051022)--(1.703010,0.057885)--
(1.688775,0.069002)--(1.668953,0.085556)--(1.644118,0.108576)--(1.611046,0.137934)--(1.566409,0.177048)--(1.509854,0.227402)--(1.439604,0.297030)--(1.355027,0.398791)--(1.241185,0.578025)--(1.095943,0.868425)--
(0.912935,1.327021)--(0.687059,2.007232)--(0.453907,2.949760)--(0.234599,4.127035)--(0.081680,5.384231)--(0.038585,6.548232)--(0.138702,7.501864)--(0.388518,8.120160)--(0.743024,8.338031)--(1.141607,8.262070)--
(1.547221,8.058635)--(1.928762,7.816291)--(2.296197,7.543291)--(2.657751,7.243239)--(3.016039,6.923077)--(3.373633,6.588483)--(3.731015,6.244509)--(4.087363,5.896069)--(4.440625,5.547139)--(4.787748,5.202023)--
(5.124864,4.865908)--(5.447865,4.544341)--(5.751513,4.242322)--(6.029328,3.964966)--(6.270366,3.724911)--(6.482331,3.513949)--(6.657636,3.340107)--(6.800788,3.197472)--(6.915040,3.083422)--(7.006061,2.993007)--
(7.079178,2.920271)--(7.140316,2.859289)--(7.190329,2.809350)--(7.230316,2.769484)--(7.259923,2.740077)--(7.282717,2.717283)--(7.299690,2.700310)--(7.310894,2.689106)--(7.319933,2.680067)--(7.327189,2.672811)--
(7.334170,2.665830)--(7.340473,2.659527)--(7.343902,2.656098)--(7.345917,2.654083)--(7.346873,2.653127)--(7.346920,2.653080)--(7.346783,2.653217)--(7.346683,2.653317)--(7.346680,2.653320)--(7.346719,2.653281)--
(7.346939,2.653061)--(7.347539,2.652461)--(7.348243,2.651757)--(7.345679,2.654321)--(7.345133,2.654867)--(7.343750,2.656250)--(7.345133,2.654867)--(7.358491,2.641509)--(7.345133,2.654867)--(7.375000,2.625000)--
(7.368421,2.631579)--cycle;
\end{tikzpicture}

\end{document}

Answer 1

Disclaimer: I am not a colourosopher and this is the first time I have ever touched colorimetry. Be warned.

An elegant approach to your problem is functional shading. It allows for a very general solution, easily adjustable to other analogous problems (read: other colour spaces).

On close inspection your dataset seems botched, so I'm just going to ignore it and use a cleaner one.

I referred to CIE 1931 for colorimetric data and I wrote down the origin of every dataset.

I took my time and wrote some simple type 4 helper functions that may be of general interest.

The interesting part is relatively short, at the bottom:

\documentclass{standalone}
\usepackage{tikz}

% ------------------------------------------------------------------- RAW DATA

% DATASET ORIGIN:
%  http://steve.hollasch.net/cgindex/color/freq-rgb.html
% Spectral stimuli colors - CIE 1931
\def\spectralLocus{ % xy coordinates from 390nm to 700nm in steps of 5nm
  (0.1738,0.0049)(0.1736,0.0049)(0.1733,0.0048)(0.1730,0.0048)(0.1726,0.0048)
  (0.1721,0.0048)(0.1714,0.0051)(0.1703,0.0058)(0.1689,0.0069)(0.1669,0.0086)
  (0.1644,0.0109)(0.1611,0.0138)(0.1566,0.0177)(0.1510,0.0227)(0.1440,0.0297)
  (0.1355,0.0399)(0.1241,0.0578)(0.1096,0.0868)(0.0913,0.1327)(0.0687,0.2007)
  (0.0454,0.2950)(0.0235,0.4127)(0.0082,0.5384)(0.0039,0.6548)(0.0139,0.7502)
  (0.0389,0.8120)(0.0743,0.8338)(0.1142,0.8262)(0.1547,0.8059)(0.1929,0.7816)
  (0.2296,0.7543)(0.2658,0.7243)(0.3016,0.6923)(0.3373,0.6589)(0.3731,0.6245)
  (0.4087,0.5896)(0.4441,0.5547)(0.4788,0.5202)(0.5125,0.4866)(0.5448,0.4544)
  (0.5752,0.4242)(0.6029,0.3965)(0.6270,0.3725)(0.6482,0.3514)(0.6658,0.3340)
  (0.6801,0.3197)(0.6915,0.3083)(0.7006,0.2993)(0.7079,0.2920)(0.7140,0.2859)
  (0.7190,0.2809)(0.7230,0.2770)(0.7260,0.2740)(0.7283,0.2717)(0.7300,0.2700)
  (0.7311,0.2689)(0.7320,0.2680)(0.7327,0.2673)(0.7334,0.2666)(0.7340,0.2660)
  (0.7344,0.2656)(0.7346,0.2654)(0.7347,0.2653)}

% DATASET ORIGIN:
%  http://www.vendian.org/mncharity/dir3/blackbody/UnstableURLs/bbr_color.html
% Blackbody colors - CIE 1931
\def\planckianLocus{ % xy coordinates from 1000K to 40000K in steps of 100K
  (0.6499,0.3474)(0.6361,0.3594)(0.6226,0.3703)(0.6095,0.3801)(0.5966,0.3887)
  (0.5841,0.3962)(0.5720,0.4025)(0.5601,0.4076)(0.5486,0.4118)(0.5375,0.4150)
  (0.5267,0.4173)(0.5162,0.4188)(0.5062,0.4196)(0.4965,0.4198)(0.4872,0.4194)
  (0.4782,0.4186)(0.4696,0.4173)(0.4614,0.4158)(0.4535,0.4139)(0.4460,0.4118)
  (0.4388,0.4095)(0.4320,0.4070)(0.4254,0.4044)(0.4192,0.4018)(0.4132,0.3990)
  (0.4075,0.3962)(0.4021,0.3934)(0.3969,0.3905)(0.3919,0.3877)(0.3872,0.3849)
  (0.3827,0.3820)(0.3784,0.3793)(0.3743,0.3765)(0.3704,0.3738)(0.3666,0.3711)
  (0.3631,0.3685)(0.3596,0.3659)(0.3563,0.3634)(0.3532,0.3609)(0.3502,0.3585)
  (0.3473,0.3561)(0.3446,0.3538)(0.3419,0.3516)(0.3394,0.3494)(0.3369,0.3472)
  (0.3346,0.3451)(0.3323,0.3431)(0.3302,0.3411)(0.3281,0.3392)(0.3261,0.3373)
  (0.3242,0.3355)(0.3223,0.3337)(0.3205,0.3319)(0.3188,0.3302)(0.3171,0.3286)
  (0.3155,0.3270)(0.3140,0.3254)(0.3125,0.3238)(0.3110,0.3224)(0.3097,0.3209)
  (0.3083,0.3195)(0.3070,0.3181)(0.3058,0.3168)(0.3045,0.3154)(0.3034,0.3142)
  (0.3022,0.3129)(0.3011,0.3117)(0.3000,0.3105)(0.2990,0.3094)(0.2980,0.3082)
  (0.2970,0.3071)(0.2961,0.3061)(0.2952,0.3050)(0.2943,0.3040)(0.2934,0.3030)
  (0.2926,0.3020)(0.2917,0.3011)(0.2910,0.3001)(0.2902,0.2992)(0.2894,0.2983)
  (0.2887,0.2975)(0.2880,0.2966)(0.2873,0.2958)(0.2866,0.2950)(0.2860,0.2942)
  (0.2853,0.2934)(0.2847,0.2927)(0.2841,0.2919)(0.2835,0.2912)(0.2829,0.2905)
  (0.2824,0.2898)(0.2818,0.2891)(0.2813,0.2884)(0.2807,0.2878)(0.2802,0.2871)
  (0.2797,0.2865)(0.2792,0.2859)(0.2788,0.2853)(0.2783,0.2847)(0.2778,0.2841)
  (0.2774,0.2836)(0.2770,0.2830)(0.2765,0.2825)(0.2761,0.2819)(0.2757,0.2814)
  (0.2753,0.2809)(0.2749,0.2804)(0.2745,0.2799)(0.2742,0.2794)(0.2738,0.2789)
  (0.2734,0.2785)(0.2731,0.2780)(0.2727,0.2776)(0.2724,0.2771)(0.2721,0.2767)
  (0.2717,0.2763)(0.2714,0.2758)(0.2711,0.2754)(0.2708,0.2750)(0.2705,0.2746)
  (0.2702,0.2742)(0.2699,0.2738)(0.2696,0.2735)(0.2694,0.2731)(0.2691,0.2727)
  (0.2688,0.2724)(0.2686,0.2720)(0.2683,0.2717)(0.2680,0.2713)(0.2678,0.2710)
  (0.2675,0.2707)(0.2673,0.2703)(0.2671,0.2700)(0.2668,0.2697)(0.2666,0.2694)
  (0.2664,0.2691)(0.2662,0.2688)(0.2659,0.2685)(0.2657,0.2682)(0.2655,0.2679)
  (0.2653,0.2676)(0.2651,0.2673)(0.2649,0.2671)(0.2647,0.2668)(0.2645,0.2665)
  (0.2643,0.2663)(0.2641,0.2660)(0.2639,0.2657)(0.2638,0.2655)(0.2636,0.2652)
  (0.2634,0.2650)(0.2632,0.2648)(0.2631,0.2645)(0.2629,0.2643)(0.2627,0.2641)
  (0.2626,0.2638)(0.2624,0.2636)(0.2622,0.2634)(0.2621,0.2632)(0.2619,0.2629)
  (0.2618,0.2627)(0.2616,0.2625)(0.2615,0.2623)(0.2613,0.2621)(0.2612,0.2619)
  (0.2610,0.2617)(0.2609,0.2615)(0.2608,0.2613)(0.2606,0.2611)(0.2605,0.2609)
  (0.2604,0.2607)(0.2602,0.2606)(0.2601,0.2604)(0.2600,0.2602)(0.2598,0.2600)
  (0.2597,0.2598)(0.2596,0.2597)(0.2595,0.2595)(0.2593,0.2593)(0.2592,0.2592)
  (0.2591,0.2590)(0.2590,0.2588)(0.2589,0.2587)(0.2588,0.2585)(0.2587,0.2584)
  (0.2586,0.2582)(0.2584,0.2580)(0.2583,0.2579)(0.2582,0.2577)(0.2581,0.2576)
  (0.2580,0.2574)(0.2579,0.2573)(0.2578,0.2572)(0.2577,0.2570)(0.2576,0.2569)
  (0.2575,0.2567)(0.2574,0.2566)(0.2573,0.2565)(0.2572,0.2563)(0.2571,0.2562)
  (0.2571,0.2561)(0.2570,0.2559)(0.2569,0.2558)(0.2568,0.2557)(0.2567,0.2555)
  (0.2566,0.2554)(0.2565,0.2553)(0.2564,0.2552)(0.2564,0.2550)(0.2563,0.2549)
  (0.2562,0.2548)(0.2561,0.2547)(0.2560,0.2546)(0.2559,0.2545)(0.2559,0.2543)
  (0.2558,0.2542)(0.2557,0.2541)(0.2556,0.2540)(0.2556,0.2539)(0.2555,0.2538)
  (0.2554,0.2537)(0.2553,0.2536)(0.2553,0.2535)(0.2552,0.2534)(0.2551,0.2533)
  (0.2551,0.2532)(0.2550,0.2531)(0.2549,0.2530)(0.2548,0.2529)(0.2548,0.2528)
  (0.2547,0.2527)(0.2546,0.2526)(0.2546,0.2525)(0.2545,0.2524)(0.2544,0.2523)
  (0.2544,0.2522)(0.2543,0.2521)(0.2543,0.2520)(0.2542,0.2519)(0.2541,0.2518)
  (0.2541,0.2517)(0.2540,0.2516)(0.2540,0.2516)(0.2539,0.2515)(0.2538,0.2514)
  (0.2538,0.2513)(0.2537,0.2512)(0.2537,0.2511)(0.2536,0.2511)(0.2535,0.2510)
  (0.2535,0.2509)(0.2534,0.2508)(0.2534,0.2507)(0.2533,0.2507)(0.2533,0.2506)
  (0.2532,0.2505)(0.2532,0.2504)(0.2531,0.2503)(0.2531,0.2503)(0.2530,0.2502)
  (0.2530,0.2501)(0.2529,0.2500)(0.2529,0.2500)(0.2528,0.2499)(0.2528,0.2498)
  (0.2527,0.2497)(0.2527,0.2497)(0.2526,0.2496)(0.2526,0.2495)(0.2525,0.2495)
  (0.2525,0.2494)(0.2524,0.2493)(0.2524,0.2493)(0.2523,0.2492)(0.2523,0.2491)
  (0.2523,0.2491)(0.2522,0.2490)(0.2522,0.2489)(0.2521,0.2489)(0.2521,0.2488)
  (0.2520,0.2487)(0.2520,0.2487)(0.2519,0.2486)(0.2519,0.2485)(0.2519,0.2485)
  (0.2518,0.2484)(0.2518,0.2484)(0.2517,0.2483)(0.2517,0.2482)(0.2517,0.2482)
  (0.2516,0.2481)(0.2516,0.2481)(0.2515,0.2480)(0.2515,0.2480)(0.2515,0.2479)
  (0.2514,0.2478)(0.2514,0.2478)(0.2513,0.2477)(0.2513,0.2477)(0.2513,0.2476)
  (0.2512,0.2476)(0.2512,0.2475)(0.2512,0.2474)(0.2511,0.2474)(0.2511,0.2473)
  (0.2511,0.2473)(0.2510,0.2472)(0.2510,0.2472)(0.2509,0.2471)(0.2509,0.2471)
  (0.2509,0.2470)(0.2508,0.2470)(0.2508,0.2469)(0.2508,0.2469)(0.2507,0.2468)
  (0.2507,0.2468)(0.2507,0.2467)(0.2506,0.2467)(0.2506,0.2466)(0.2506,0.2466)
  (0.2505,0.2465)(0.2505,0.2465)(0.2505,0.2464)(0.2505,0.2464)(0.2504,0.2463)
  (0.2504,0.2463)(0.2504,0.2463)(0.2503,0.2462)(0.2503,0.2462)(0.2503,0.2461)
  (0.2502,0.2461)(0.2502,0.2460)(0.2502,0.2460)(0.2502,0.2459)(0.2501,0.2459)
  (0.2501,0.2459)(0.2501,0.2458)(0.2500,0.2458)(0.2500,0.2457)(0.2500,0.2457)
  (0.2500,0.2456)(0.2499,0.2456)(0.2499,0.2456)(0.2499,0.2455)(0.2498,0.2455)
  (0.2498,0.2454)(0.2498,0.2454)(0.2498,0.2454)(0.2497,0.2453)(0.2497,0.2453)
  (0.2497,0.2452)(0.2497,0.2452)(0.2496,0.2452)(0.2496,0.2451)(0.2496,0.2451)
  (0.2496,0.2450)(0.2495,0.2450)(0.2495,0.2450)(0.2495,0.2449)(0.2495,0.2449)
  (0.2494,0.2449)(0.2494,0.2448)(0.2494,0.2448)(0.2494,0.2447)(0.2493,0.2447)
  (0.2493,0.2447)(0.2493,0.2446)(0.2493,0.2446)(0.2492,0.2446)(0.2492,0.2445)
  (0.2492,0.2445)(0.2492,0.2445)(0.2491,0.2444)(0.2491,0.2444)(0.2491,0.2444)
  (0.2491,0.2443)(0.2491,0.2443)(0.2490,0.2443)(0.2490,0.2442)(0.2490,0.2442)
  (0.2490,0.2442)(0.2489,0.2441)(0.2489,0.2441)(0.2489,0.2441)(0.2489,0.2440)
  (0.2489,0.2440)(0.2488,0.2440)(0.2488,0.2439)(0.2488,0.2439)(0.2488,0.2439)
  (0.2487,0.2438)}

% ---------------------------------------------- sRGB COLORSPACE SPECIFICATION

% DATASET ORIGIN: http://www.color.org/sRGB.xalter

% CIE chromaticities for ITU-R BT.709 reference primaries
\def\primariesLoci{
  (0.6400,0.3300)  % R
  (0.3000,0.6000)  % G
  (0.1500,0.0600)} % B

% CIE standard illuminant D65
\def\whitepointLocus{
  (0.3127,0.3290)}

% Derived transformation matrix
\def\XYZtoRGB{
  { 3.2410}{-1.5374}{-0.4986}
  {-0.9692}{ 1.8760}{ 0.0416}
  { 0.0556}{-0.2040}{ 1.0570}}

 % Linear color to gamma corrected transform
\def\gammaCorrect{
  dup 0.0031308 le                    % if < 0.0031308
  {12.92 mul}                         % then linear transform
  {1 2.4 div exp 1.055 mul -0.055 add}% else power transform
  ifelse }

% ------------------------------------------------------------- TYPE 4 HELPERS

\def\scalarProduct#1#2#3{
  #3 mul     exch
  #2 mul add exch
  #1 mul add }

\def\applyMatrix#1#2#3#4#5#6#7#8#9{
  3 copy 3 copy
  \scalarProduct{#7}{#8}{#9} 7 1 roll
  \scalarProduct{#4}{#5}{#6} 5 1 roll
  \scalarProduct{#1}{#2}{#3} 3 1 roll }

\def\xyYtoXYZ{                        % x y Y
  3 copy 3 1 roll                     % x y Y Y x y
  add neg 1 add mul 2 index div       % x y Y Y*(-(x+y)+1)/y=Z
  4 1 roll                            % Z x y Y
  dup                                 % Z x y Y Y=Y
  5 1 roll                            % Y Z x y Y
  3 2 roll                            % Y Z y Y x
  mul exch div                        % Y Z Y*x/y=X
  3 1 roll }                          % X Y Z

\def\gammaCorrectVector{
  \gammaCorrect 3 1 roll
  \gammaCorrect 3 1 roll
  \gammaCorrect 3 1 roll}

% -------------------------------------------------------------------- DRAWING

\begin{document}
\begin{tikzpicture}

\pgfdeclarefunctionalshading{colorspace}
  {\pgfpointorigin}{\pgfpoint{1000bp}{1000bp}}{}{
    1000 div exch 1000 div exch       % x y   (chromaticity)
    1.0                               % x y Y (chromaticity+luminance)
    \xyYtoXYZ                         % X Y Z (XYZ)
    \expandafter\applyMatrix\XYZtoRGB % R G B (sRGB linear)
    \gammaCorrectVector }             % R G B (sRGB gamma corrected)

\begin{scope} [shift={(-500bp,-500bp)}, scale=100bp/1cm]
  % Background + viewport
  \fill [black] (-1,-1) rectangle (11,11);
  % xy grid
  \draw [dashed, gray] grid (10,10);
  \begin{scope} [scale=10]
    % Spectral locus marks
    \path [mark=*, mark repeat=2, white] 
      plot [mark size=0.10, mark phase=1] coordinates {\spectralLocus}
      plot [mark size=0.05, mark phase=2] coordinates {\spectralLocus};
    % Smooth spectral locus contour for clipping
    \clip [smooth] plot coordinates {\spectralLocus} -- cycle;
    % sRGB color space
    \pgfuseshading{colorspace}
    % Standard illuminant mark
    \draw [gray] \whitepointLocus circle (0.005);
    % Reference primaries gamut
    \fill [black, even odd rule, opacity=0.5]
      rectangle +(1,1) plot coordinates {\primariesLoci} -- cycle;
    % Planckian locus markings
    \path [mark=*,gray]
      plot [mark size=0.05, mark repeat=10] coordinates {\planckianLocus}
      plot [mark size=0.01, mark repeat=1 ] coordinates {\planckianLocus};
  \end{scope}
\end{scope}

\end{tikzpicture}
\end{document}

Here is the result:

The image is quite big, so I suggest you open it and zoom in.

The grid is a graduation on the domain of chromaticity.

As you can see I also drew graduations along the spectral locus (white, from 390nm to 700nm, thin ticks every 5nm, thick ticks every 10nm) and the planckian locus (grey, from 1000K to 40000K, thin ticks every 100K, thick ticks every 1000K).

If my colorimetry is sound, this is a full luminance chromaticity diagram of the sRGB color space, with gamma correction. The triangle is the gamut for the ITU-R BT.709 reference primaries. The illuminant is a standard D65, marked with a grey circle.