{"action":"created","issue":{"url":"https://api.github.com/repos/colour-science/colour/issues/220","repository_url":"https://api.github.com/repos/colour-science/colour","labels_url":"https://api.github.com/repos/colour-science/colour/issues/220/labels{/name}","comments_url":"https://api.github.com/repos/colour-science/colour/issues/220/comments","events_url":"https://api.github.com/repos/colour-science/colour/issues/220/events","html_url":"https://github.com/colour-science/colour/issues/220","id":110149345,"number":220,"title":"About illuminants chromaticity coordinates calculation.","user":{"login":"henczati","id":5007476,"avatar_url":"https://avatars.githubusercontent.com/u/5007476?v=3","gravatar_id":"","url":"https://api.github.com/users/henczati","html_url":"https://github.com/henczati","followers_url":"https://api.github.com/users/henczati/followers","following_url":"https://api.github.com/users/henczati/following{/other_user}","gists_url":"https://api.github.com/users/henczati/gists{/gist_id}","starred_url":"https://api.github.com/users/henczati/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/henczati/subscriptions","organizations_url":"https://api.github.com/users/henczati/orgs","repos_url":"https://api.github.com/users/henczati/repos","events_url":"https://api.github.com/users/henczati/events{/privacy}","received_events_url":"https://api.github.com/users/henczati/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/colour-science/colour/labels/Discussion","name":"Discussion","color":"00cc00"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/colour-science/colour/milestones/4","html_url":"https://github.com/colour-science/colour/milestones/v9.9.9","labels_url":"https://api.github.com/repos/colour-science/colour/milestones/4/labels","id":767582,"number":4,"title":"v9.9.9","description":"Colour v9.9.9 - Legendary Milestone.\r\n\r\nThis milestone is used to park future features.","creator":{"login":"KelSolaar","id":99779,"avatar_url":"https://avatars.githubusercontent.com/u/99779?v=3","gravatar_id":"","url":"https://api.github.com/users/KelSolaar","html_url":"https://github.com/KelSolaar","followers_url":"https://api.github.com/users/KelSolaar/followers","following_url":"https://api.github.com/users/KelSolaar/following{/other_user}","gists_url":"https://api.github.com/users/KelSolaar/gists{/gist_id}","starred_url":"https://api.github.com/users/KelSolaar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/KelSolaar/subscriptions","organizations_url":"https://api.github.com/users/KelSolaar/orgs","repos_url":"https://api.github.com/users/KelSolaar/repos","events_url":"https://api.github.com/users/KelSolaar/events{/privacy}","received_events_url":"https://api.github.com/users/KelSolaar/received_events","type":"User","site_admin":false},"open_issues":41,"closed_issues":2,"state":"open","created_at":"2014-08-27T15:47:37Z","updated_at":"2016-04-26T03:51:12Z","due_on":null,"closed_at":null},"comments":4,"created_at":"2015-10-07T04:15:03Z","updated_at":"2016-05-06T09:56:15Z","closed_at":null,"body":"Shouldn't these give the same results?\r\nWhich should be preferred?\r\n\r\nIn:\r\n```python\r\n# Pre-computed whitepoint\r\nxy1 = colour.ILLUMINANTS['cie_2_1931']['D65']\r\n\r\n# Spectrum of ill.-on-perfect-reflector to XYZ to xy\r\nxy2 = colour.XYZ_to_xy(colour.spectral_to_XYZ(colour.ILLUMINANTS_RELATIVE_SPDS['D65'], colour.STANDARD_OBSERVERS_CMFS['cie_2_1931']) / 100.)\r\n\r\nprint np.array([xy1, xy2])\r\n```\r\nOut:\r\n```python\r\n[[ 0.31271     0.32902   ]\r\n [ 0.31271107  0.32900848]]\r\n```"},"comment":{"url":"https://api.github.com/repos/colour-science/colour/issues/comments/217401005","html_url":"https://github.com/colour-science/colour/issues/220#issuecomment-217401005","issue_url":"https://api.github.com/repos/colour-science/colour/issues/220","id":217401005,"user":{"login":"KevinJW","id":1186170,"avatar_url":"https://avatars.githubusercontent.com/u/1186170?v=3","gravatar_id":"","url":"https://api.github.com/users/KevinJW","html_url":"https://github.com/KevinJW","followers_url":"https://api.github.com/users/KevinJW/followers","following_url":"https://api.github.com/users/KevinJW/following{/other_user}","gists_url":"https://api.github.com/users/KevinJW/gists{/gist_id}","starred_url":"https://api.github.com/users/KevinJW/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/KevinJW/subscriptions","organizations_url":"https://api.github.com/users/KevinJW/orgs","repos_url":"https://api.github.com/users/KevinJW/repos","events_url":"https://api.github.com/users/KevinJW/events{/privacy}","received_events_url":"https://api.github.com/users/KevinJW/received_events","type":"User","site_admin":false},"created_at":"2016-05-06T09:56:15Z","updated_at":"2016-05-06T09:56:15Z","body":"ah yes, I had that problem when dealing with colour spaces do you use the\n'official' number so your matrix is the same as those often specified (best\nfor when inter-operating with other tools) or use more precise definitions,\nderive from XYZ or specific co-ordinates, etc. I did not come to a good\nconclusion so I implemented all of them in my plugins. I did not consider\nderiving from spectral data. as that was one step too far for my\nrequirements.\n\nKevin\n​\n"}}