How much worse is sRGB than L*a*b* when computing the eucleidan distance between colors?

Question

L*a*b* is the best way of doing it, but converting to it is complicated, and I'm lazy. How much accuracy am I giving up by operating on sRGB directly?

Answer 1

Telling you they are different or that LAB is setup to be more uniform with regard to human eyes doesn't answer the question. Yeah, LAB is more accurate. How much more accurate? --- 0.0982515 or 9.8%. Well, rather they are 9.8% different from each other, not necessarily wrong. And, this can be dropped to 8.42% if we use a weighted Euclidean distance specifically found through brute force checking all the values.

R_WEIGHT = 0.22216091748149788;
G_WEIGHT = 0.4288860259783791;
B_WEIGHT = 0.34895305654012304;

But, this metric is just the distance between the various color distances and more properly is if you tried to normalize the color-spaces to the best that you could how much difference percentwise would be had on average if you compared every RGB color. On average the distance will be 9.8% different

Normalization Factor ADDATIVE avg: 255.0 max: 720.0
Normalization Factor EUCLIDEAN avg: 169.0818947154052 max: 415.69219381653056
Normalization Factor HSL avg: 0.741431462109039 max: 1.8823529411764708
Normalization Factor HSV avg: 0.7566196050164451 max: 1.882352948188782
Normalization Factor HunterLab avg: 75.3032683118924 max: 268.8032191014305
Normalization Factor Lab-DeltaC avg: -1.1623747563667267E-13 max: 127.81288917107821
Normalization Factor Lab-DeltaCMC avg: 100.6405383086951 max: 474.0965775740221
Normalization Factor Lab-DeltaE avg: 83.4564412748037 max: 247.08807561172128
Normalization Factor Lab-DeltaE00 avg: 45.5474588950764 max: 123.15992607129513
Normalization Factor Lab-DeltaE94 avg: 40.119951741844346 max: 143.17090215785484
Normalization Factor Lab-DeltaH avg: 66.09871579546063 max: 240.97572142402947
Normalization Factor Luv avg: 102.29412243880533 max: 259.53530615111254
Normalization Factor REDMEAN avg: 292.0100684630404 max: 719.8437330421096
Normalization Factor SQUAREDEUCLIDEAN avg: 32640.0 max: 172800.0
Normalization Factor VALUE avg: 0.21317036377052911 max: 0.9411764740943909
Normalization Factor WEIGHTEDEUCLIDEAN avg: 57.53562833117014 max: 143.00998320039014
Normalization Factor XYZ avg: 46.40994451724809 max: 153.15677688654787
Normalization Factor Yxy avg: 22.99618945090987 max: 87.09986870423464
Comparing ColorDistance ADDATIVE and EUCLIDEAN
Error 882165.4112085595 overall.
Average error 0.05258115596822259
Average denormal error ADDATIVE 37.85843229712027 given norm factor of 720.0
Average denormal error EUCLIDEAN 21.857576077839607 given norm factor of 415.69219381653056
Error sq 72486.58944378965 overall.
Error sq 0.004320537414776662 average. 

Comparing ColorDistance EUCLIDEAN and HSL
Error 1113120.1254317532 overall.
Average error 0.06634712966869791
Average denormal error EUCLIDEAN 27.579983885410854 given norm factor of 415.69219381653056
Average denormal error HSL 0.12488871467049019 given norm factor of 1.8823529411764708
Error sq 133244.92221877474 overall.
Error sq 0.007942016256974622 average. 


Comparing ColorDistance EUCLIDEAN and HSV
Error 1187968.6663541289 overall.
Average error 0.0708084503623324
Average denormal error EUCLIDEAN 29.43452007186686 given norm factor of 415.69219381653056
Average denormal error HSV 0.13328649529621542 given norm factor of 1.882352948188782
Error sq 145746.11024892316 overall.
Error sq 0.008687145128781984 average. 

Comparing ColorDistance EUCLIDEAN and Lab-DeltaC
Error 7236523.891443457 overall.
Average error 0.4313304359581147
Average denormal error EUCLIDEAN 179.30069518326926 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaC 55.12958920722736 given norm factor of 127.81288917107821
Error sq 4590836.705671633 overall.
Error sq 0.2736351910633822 average. 


Comparing ColorDistance EUCLIDEAN and Lab-DeltaCMC
Error 3541568.809431064 overall.
Average error 0.21109395083374166
Average denormal error EUCLIDEAN 87.75010752347691 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaCMC 100.07891963685582 given norm factor of 474.0965775740221
Error sq 1042161.9371561127 overall.
Error sq 0.06211769206262307 average. 


Comparing ColorDistance EUCLIDEAN and Lab-DeltaE
Error 1779551.2627665845 overall.
Average error 0.10606952087680009
Average denormal error EUCLIDEAN 44.09227183034532 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaE 26.20851379450583 given norm factor of 247.08807561172128
Error sq 307486.9379937461 overall.
Error sq 0.018327649712189798 average. 


Comparing ColorDistance EUCLIDEAN and Lab-DeltaE00
Error 1648388.272332477 overall.
Average error 0.09825159742429715
Average denormal error EUCLIDEAN 40.84242207928467 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaE00 12.100659475163088 given norm factor of 123.15992607129513
Error sq 246987.34052658826 overall.
Error sq 0.014721592696105734 average. 


Comparing ColorDistance EUCLIDEAN and Lab-DeltaE94
Error 2377969.0946470746 overall.
Average error 0.14173800317329613
Average denormal error EUCLIDEAN 58.919381486281836 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaE94 20.2927577843737 given norm factor of 143.17090215785484
Error sq 500773.6503892357 overall.
Error sq 0.02984843554432605 average. 


Comparing ColorDistance EUCLIDEAN and Lab-DeltaH
Error 2629926.892562283 overall.
Average error 0.156778229453778
Average denormal error EUCLIDEAN 65.17148614431238 given norm factor of 415.69219381653056
Average denormal error Lab-DeltaH 37.77974694620618 given norm factor of 240.97572142402947
Error sq 668078.9918658325 overall.
Error sq 0.039826293946119515 average. 


Comparing ColorDistance EUCLIDEAN and Luv
Error 1668698.740508611 overall.
Average error 0.0994621956651575
Average denormal error EUCLIDEAN 41.34565831785834 given norm factor of 415.69219381653056
Average denormal error Luv 25.81395140241851 given norm factor of 259.53530615111254
Error sq 264818.27519204654 overall.
Error sq 0.015784399222853573 average. 


Comparing ColorDistance EUCLIDEAN and REDMEAN
Error 426675.1181944958 overall.
Average error 0.02543181885448073
Average denormal error EUCLIDEAN 10.5718085723637 given norm factor of 415.69219381653056
Average denormal error REDMEAN 18.306935422260118 given norm factor of 719.8437330421096
Error sq 16138.58095303156 overall.
Error sq 9.619343848843312E-4 average. 


Comparing ColorDistance EUCLIDEAN and SQUAREDEUCLIDEAN
Error 3655066.3889753376 overall.
Average error 0.21785893374534473
Average denormal error EUCLIDEAN 90.56225811113254 given norm factor of 415.69219381653056
Average denormal error SQUAREDEUCLIDEAN 37646.02375119557 given norm factor of 172800.0
Error sq 822754.7419210516 overall.
Error sq 0.04904000412947247 average. 


Comparing ColorDistance EUCLIDEAN and WEIGHTEDEUCLIDEAN
Error 815165.7577823844 overall.
Average error 0.04858766542568114
Average denormal error EUCLIDEAN 20.197513233224985 given norm factor of 415.69219381653056
Average denormal error WEIGHTEDEUCLIDEAN 6.9485212162728365 given norm factor of 143.00998320039014
Error sq 65574.38516195789 overall.
Error sq 0.003908537933943146 average. 


Comparing ColorDistance EUCLIDEAN and XYZ
Error 2096937.5867775835 overall.
Average error 0.12498721997604272
Average denormal error EUCLIDEAN 51.95621167087049 given norm factor of 415.69219381653056
Average denormal error XYZ 19.142639763540654 given norm factor of 153.15677688654787
Error sq 409322.60961734696 overall.
Error sq 0.024397528744777856 average. 


Comparing ColorDistance EUCLIDEAN and Yxy
Error 3181581.405408212 overall.
Average error 0.18972965961993687
Average denormal error EUCLIDEAN 78.86913843947517 given norm factor of 415.69219381653056
Average denormal error Yxy 16.52542844219563 given norm factor of 87.09986870423464
Error sq 915271.5869413229 overall.
Error sq 0.05458108548000393 average. 


Comparing ColorDistance Lab-DeltaE and Lab-DeltaE00
Error 1181612.8977208994 overall.
Average error 0.07042961703067419
Average denormal error Lab-DeltaE 17.402318538179795 given norm factor of 247.08807561172128
Average denormal error Lab-DeltaE00 8.67410642672746 given norm factor of 123.15992607129513
Error sq 135051.67995998668 overall.
Error sq 0.008049707410334747 average. 


Comparing ColorDistance Lab-DeltaE and Lab-DeltaE94
Error 1487348.669100167 overall.
Average error 0.08865288907886547
Average denormal error Lab-DeltaE 21.90507175991625 given norm factor of 247.08807561172128
Average denormal error Lab-DeltaE94 12.692514108321406 given norm factor of 143.17090215785484
Error sq 237498.6506322098 overall.
Error sq 0.014156022705567468 average. 


Comparing ColorDistance Lab-DeltaE and Lab-DeltaH
Error 1083222.1828686255 overall.
Average error 0.06457428775510259
Average denormal error Lab-DeltaE 15.955536495405836 given norm factor of 247.08807561172128
Average denormal error Lab-DeltaH 15.560835577228719 given norm factor of 240.97572142402947
Error sq 149350.29968639204 overall.
Error sq 0.008903241994841557 average. 


Comparing ColorDistance Lab-DeltaE and Luv
Error 1121018.8188130187 overall.
Average error 0.06681792848187797
Average denormal error Lab-DeltaE 16.509913364948847 given norm factor of 247.08807561172128
Average denormal error Luv 17.34161152492734 given norm factor of 259.53530615111254
Error sq 133849.6902796276 overall.
Error sq 0.007978063242413258 average. 


Comparing ColorDistance Lab-DeltaE and REDMEAN
Error 1659755.4393279715 overall.
Average error 0.09892913337516615
Average denormal error Lab-DeltaE 24.444209187605114 given norm factor of 247.08807561172128
Average denormal error REDMEAN 71.21351667540036 given norm factor of 719.8437330421096
Error sq 275639.6584250547 overall.
Error sq 0.016429403926435392 average. 


Comparing ColorDistance Lab-DeltaE and SQUAREDEUCLIDEAN
Error 2671818.8519034865 overall.
Average error 0.15925281357189933
Average denormal error Lab-DeltaE 39.34947124123281 given norm factor of 247.08807561172128
Average denormal error SQUAREDEUCLIDEAN 27518.886185224204 given norm factor of 172800.0
Error sq 603216.8313254007 overall.
Error sq 0.035954524953687235 average. 


Comparing ColorDistance Lab-DeltaE and VALUE
Error 3581419.7290731133 overall.
Average error 0.21346925074297865
Average denormal error Lab-DeltaE 52.7457063683586 given norm factor of 247.08807561172128
Average denormal error VALUE 0.20091223674184808 given norm factor of 0.9411764740943909
Error sq 1210148.396209585 overall.
Error sq 0.07213046528158099 average. 


Comparing ColorDistance Lab-DeltaE and WEIGHTEDEUCLIDEAN
Error 1523670.171612541 overall.
Average error 0.09081781933382398
Average denormal error Lab-DeltaE 22.44000021044754 given norm factor of 247.08807561172128
Average denormal error WEIGHTEDEUCLIDEAN 12.987854817226234 given norm factor of 143.00998320039014
Error sq 257462.09161655055 overall.
Error sq 0.015345936513933572 average. 


Comparing ColorDistance Lab-DeltaE and XYZ
Error 2319752.5479703383 overall.
Average error 0.1382680265885793
Average denormal error Lab-DeltaE 34.164380608402375 given norm factor of 247.08807561172128
Average denormal error XYZ 21.176685298770312 given norm factor of 153.15677688654787
Error sq 505285.060927206 overall.
Error sq 0.030117336566877723 average. 


Comparing ColorDistance Lab-DeltaE and Yxy
Error 2993063.370547558 overall.
Average error 0.17848762051148223
Average denormal error Lab-DeltaE 44.10216267269733 given norm factor of 247.08807561172128
Average denormal error Yxy 15.54624831188136 given norm factor of 87.09986870423464
Error sq 823338.9108924654 overall.
Error sq 0.049098794407693075 average. 


Comparing ColorDistance Lab-DeltaE00 and Lab-DeltaE94
Error 1709354.6429333724 overall.
Average error 0.10188547628720834
Average denormal error Lab-DeltaE00 12.548207727271272 given norm factor of 123.15992607129513
Average denormal error Lab-DeltaE94 14.587035556822345 given norm factor of 143.17090215785484
Error sq 308273.6545456041 overall.
Error sq 0.018374541672802214 average. 


Comparing ColorDistance Lab-DeltaE00 and Lab-DeltaH
Error 1888833.2407755286 overall.
Average error 0.11259930154701663
Average denormal error Lab-DeltaE00 13.867721654210035 given norm factor of 123.15992607129513
Average denormal error Lab-DeltaH 27.133697922134168 given norm factor of 240.97572142402947
Error sq 344076.50288663054 overall.
Error sq 0.020511484586043925 average. 


Comparing ColorDistance Lab-DeltaE00 and Luv
Error 1496679.6176154092 overall.
Average error 0.08920905695053394
Average denormal error Lab-DeltaE00 10.986980858917716 given norm factor of 123.15992607129513
Average denormal error Luv 23.15289990710886 given norm factor of 259.53530615111254
Error sq 226094.78024689248 overall.
Error sq 0.013476299062186031 average. 


Comparing ColorDistance Lab-DeltaE00 and REDMEAN
Error 1521260.436384438 overall.
Average error 0.09067418792155016
Average denormal error Lab-DeltaE00 11.16742628099284 given norm factor of 123.15992607129513
Average denormal error REDMEAN 65.27124592401043 given norm factor of 719.8437330421096
Error sq 208919.71687992578 overall.
Error sq 0.012452585511203157 average. 


Comparing ColorDistance Lab-DeltaE00 and SQUAREDEUCLIDEAN
Error 3104213.380245159 overall.
Average error 0.18502553583652728
Average denormal error Lab-DeltaE00 22.787731314928468 given norm factor of 123.15992607129513
Average denormal error SQUAREDEUCLIDEAN 31972.412592551915 given norm factor of 172800.0
Error sq 788967.2130553125 overall.
Error sq 0.047026110473591835 average. 


Comparing ColorDistance Lab-DeltaE00 and VALUE
Error 3600134.9236918814 overall.
Average error 0.21458476327013262
Average denormal error Lab-DeltaE00 26.428243580375902 given norm factor of 123.15992607129513
Average denormal error VALUE 0.20196213088896298 given norm factor of 0.9411764740943909
Error sq 1242546.8007973088 overall.
Error sq 0.07406156067832165 average. 


Comparing ColorDistance Lab-DeltaE00 and WEIGHTEDEUCLIDEAN
Error 1412664.8794017686 overall.
Average error 0.08420138832341245
Average denormal error Lab-DeltaE00 10.37023676101189 given norm factor of 123.15992607129513
Average denormal error WEIGHTEDEUCLIDEAN 12.04163912958074 given norm factor of 143.00998320039014
Error sq 184891.61644232064 overall.
Error sq 0.011020399119992294 average. 


Comparing ColorDistance Lab-DeltaE00 and XYZ
Error 2301570.034969217 overall.
Average error 0.13718426436002357
Average denormal error Lab-DeltaE00 16.89560385672551 given norm factor of 123.15992607129513
Average denormal error XYZ 21.010699768933332 given norm factor of 153.15677688654787
Error sq 501877.17658142577 overall.
Error sq 0.029914210831011877 average. 


Comparing ColorDistance Lab-DeltaE00 and Yxy
Error 2850057.544353629 overall.
Average error 0.16995964549838938
Average denormal error Lab-DeltaE00 20.932217374685163 given norm factor of 123.15992607129513
Average denormal error Yxy 14.803462807927978 given norm factor of 87.09986870423464
Error sq 782527.0097816944 overall.
Error sq 0.04666502732160602 average. 


Comparing ColorDistance Lab-DeltaE94 and Lab-DeltaH
Error 1660983.5416123287 overall.
Average error 0.09901646298317375
Average denormal error Lab-DeltaE94 14.176276333780825 given norm factor of 143.17090215785484
Average denormal error Lab-DeltaH 23.860563600226005 given norm factor of 240.97572142402947
Error sq 301313.1261624993 overall.
Error sq 0.017962224944175223 average. 


Comparing ColorDistance Lab-DeltaE94 and Luv
Error 2274933.4136145706 overall.
Average error 0.13559659800616328
Average denormal error Lab-DeltaE94 19.413487266078377 given norm factor of 143.17090215785484
Average denormal error Luv 35.19210457657892 given norm factor of 259.53530615111254
Error sq 505622.3280915819 overall.
Error sq 0.03013743925640475 average. 


Comparing ColorDistance Lab-DeltaE94 and REDMEAN
Error 2317582.683652623 overall.
Average error 0.1381386925967111
Average denormal error Lab-DeltaE94 19.777441241977712 given norm factor of 143.17090215785484
Average denormal error REDMEAN 99.43827215637296 given norm factor of 719.8437330421096
Error sq 467018.8971285333 overall.
Error sq 0.027836495466740923 average. 


Comparing ColorDistance Lab-DeltaE94 and SQUAREDEUCLIDEAN
Error 1952276.974309023 overall.
Average error 0.11636477555686373
Average denormal error Lab-DeltaE94 16.660049895872476 given norm factor of 143.17090215785484
Average denormal error SQUAREDEUCLIDEAN 20107.833216226052 given norm factor of 172800.0
Error sq 356616.290075466 overall.
Error sq 0.02125598729106581 average. 


Comparing ColorDistance Lab-DeltaE94 and VALUE
Error 2873827.8648674106 overall.
Average error 0.1712934890310413
Average denormal error Lab-DeltaE94 24.524243358340794 given norm factor of 143.17090215785484
Average denormal error VALUE 0.16121740204156168 given norm factor of 0.9411764740943909
Error sq 801494.7314424015 overall.
Error sq 0.04777280875697145 average. 


Comparing ColorDistance Lab-DeltaE94 and WEIGHTEDEUCLIDEAN
Error 2249395.1276259418 overall.
Average error 0.13407439754163872
Average denormal error Lab-DeltaE94 19.19555245230729 given norm factor of 143.17090215785484
Average denormal error WEIGHTEDEUCLIDEAN 19.17397734003218 given norm factor of 143.00998320039014
Error sq 455938.6036504245 overall.
Error sq 0.027176058509971172 average. 


Comparing ColorDistance Lab-DeltaE94 and XYZ
Error 2030610.8996925459 overall.
Average error 0.12103384135321056
Average denormal error Lab-DeltaE94 17.328524258169836 given norm factor of 143.17090215785484
Average denormal error XYZ 18.5371530358555 given norm factor of 153.15677688654787
Error sq 397674.5901417746 overall.
Error sq 0.023703252681599535 average. 


Comparing ColorDistance Lab-DeltaE94 and Yxy
Error 2467778.769513657 overall.
Average error 0.14716292506652337
Average denormal error Lab-DeltaE94 21.06944874596294 given norm factor of 143.17090215785484
Average denormal error Yxy 12.817871451425306 given norm factor of 87.09986870423464
Error sq 583243.6568776758 overall.
Error sq 0.034781011828515715 average. 

Comparing ColorDistance Luv and REDMEAN
Error 1624494.6202941916 overall.
Average error 0.09682742478216837
Average denormal error Luv 25.130135334663887 given norm factor of 259.53530615111254
Average denormal error REDMEAN 69.70061491605016 given norm factor of 719.8437330421096
Error sq 254071.4217014575 overall.
Error sq 0.015143836838093847 average. 


Comparing ColorDistance Luv and SQUAREDEUCLIDEAN
Error 3562501.35330629 overall.
Average error 0.2123416276756698
Average denormal error Luv 55.110149347430514 given norm factor of 259.53530615111254
Average denormal error SQUAREDEUCLIDEAN 36692.63326235574 given norm factor of 172800.0
Error sq 992264.6899709017 overall.
Error sq 0.059143584368878704 average. 


Comparing ColorDistance Luv and VALUE
Error 4167103.265285218 overall.
Average error 0.2483787098696958
Average denormal error Luv 64.46304450744985 given norm factor of 259.53530615111254
Average denormal error VALUE 0.23376819839527396 given norm factor of 0.9411764740943909
Error sq 1643457.2763738004 overall.
Error sq 0.09795768716179135 average. 


Comparing ColorDistance Luv and WEIGHTEDEUCLIDEAN
Error 1644441.2250673599 overall.
Average error 0.09801633507414817
Average denormal error Luv 25.438699531279074 given norm factor of 259.53530615111254
Average denormal error WEIGHTEDEUCLIDEAN 14.01731443231774 given norm factor of 143.00998320039014
Error sq 267249.95858358435 overall.
Error sq 0.0159293388476124 average. 


Comparing ColorDistance Luv and XYZ
Error 2795027.38179749 overall.
Average error 0.1665966142295295
Average denormal error Luv 43.23770327779973 given norm factor of 259.53530615111254
Average denormal error XYZ 25.515400475606338 given norm factor of 153.15677688654787
Error sq 721204.4360689361 overall.
Error sq 0.042987134222324856 average. 


Comparing ColorDistance Luv and Yxy
Error 3626577.1967255506 overall.
Average error 0.21626643151438743
Average denormal error Luv 56.128774513295156 given norm factor of 259.53530615111254
Average denormal error Yxy 18.836777790036496 given norm factor of 87.09986870423464
Error sq 1199019.0529486015 overall.
Error sq 0.07150201356063346 average. 


Comparing ColorDistance REDMEAN and SQUAREDEUCLIDEAN
Error 3636775.1933349385 overall.
Average error 0.21676869352668157
Average denormal error REDMEAN 156.03958555490746 given norm factor of 719.8437330421096
Average denormal error SQUAREDEUCLIDEAN 37457.630241410574 given norm factor of 172800.0
Error sq 830509.6077364177 overall.
Error sq 0.049502230151678185 average. 


Comparing ColorDistance REDMEAN and VALUE
Error 3600378.5359081384 overall.
Average error 0.21459928368974557
Average denormal error REDMEAN 154.47794947938917 given norm factor of 719.8437330421096
Average denormal error VALUE 0.20197579716629666 given norm factor of 0.9411764740943909
Error sq 1235907.1764258433 overall.
Error sq 0.07366580822621842 average. 


Comparing ColorDistance REDMEAN and WEIGHTEDEUCLIDEAN
Error 538308.9891520267 overall.
Average error 0.03208571607780616
Average denormal error REDMEAN 23.096701638777223 given norm factor of 719.8437330421096
Average denormal error WEIGHTEDEUCLIDEAN 4.588577717259547 given norm factor of 143.00998320039014
Error sq 28618.668188863965 overall.
Error sq 0.0017058055513420084 average. 


Comparing ColorDistance REDMEAN and XYZ
Error 2106685.4447501153 overall.
Average error 0.12556823758781643
Average denormal error REDMEAN 90.38950889673234 given norm factor of 719.8437330421096
Average denormal error XYZ 19.231626548274235 given norm factor of 153.15677688654787
Error sq 411353.7958555746 overall.
Error sq 0.024518596878980076 average. 


Comparing ColorDistance REDMEAN and Yxy
Error 2981846.251046661 overall.
Average error 0.17781870150749138
Average denormal error REDMEAN 128.0016778978532 given norm factor of 719.8437330421096
Average denormal error Yxy 15.48798555445999 given norm factor of 87.09986870423464
Error sq 800388.282174192 overall.
Error sq 0.04773016213967073 average. 


Comparing ColorDistance WEIGHTEDEUCLIDEAN and XYZ
Error 2017243.1731913008 overall.
Average error 0.12023706276364927
Average denormal error WEIGHTEDEUCLIDEAN 17.195100325893737 given norm factor of 143.00998320039014
Average denormal error XYZ 18.415120995186086 given norm factor of 153.15677688654787
Error sq 383882.5446786289 overall.
Error sq 0.022881182711042697 average. 


Comparing ColorDistance WEIGHTEDEUCLIDEAN and Yxy
Error 2884580.206807449 overall.
Average error 0.17201836164043222
Average denormal error WEIGHTEDEUCLIDEAN 24.600343008356848 given norm factor of 143.00998320039014
Average denormal error Yxy 14.982776713599199 given norm factor of 87.09986870423464
Error sq 758099.1907513536 overall.
Error sq 0.045208304642121624 average. 

This is Euclidean distance from an orange.

This is LAB Delta E from the same color.

Each diagram is read left to right, top to bottom. With a subset of all RGB colors.

LAB Delta E, isn't that great. You'd really want Delta E, 2000 if you want the best results. If you want a pretty good trade off between good and fast & easy. Redmean is actually pretty good for a colordistance formula.

You'll find the quick snippet here. http://www.compuphase.com/cmetric.htm

He's also right about Euclidean weighting. The RGB weighting (if you wanted to do that should be 22,43,35 (I averaged all colors over the entire RGB distances possible for Delta E2000 for those numbers)).

I've done a lot of work with color distance and wrote a pretty good visual comparison of the various different formula.

http://godsnotwheregodsnot.blogspot.com/2012/09/color-space-comparisons.html