Amadedewo ƒe Teƒewo Gɔmesese le Digitál Nɔnɔmetatawo Me

Amadede ƒe kpɔɖeŋu nye nukpɔsusu ƒe ɖoɖo si wotsɔ ɖea amadedewo fiana to xexlẽdzesiwo ƒe asixɔxɔwo zazã me (abe RGB alo CMYK ene), esime amadede ƒe teƒe nye amadede ƒe kpɔɖeŋu ƒe dɔwɔwɔ tɔxɛ si me woɖe nɔnɔmetatawo le. Le kpɔɖeŋu me, RGB nye amadede ƒe kpɔɖeŋu, gake sRGB kple Adobe RGB nye amadede ƒe teƒe tɔxɛ siwo wotu ɖe RGB ƒe kpɔɖeŋu dzi, eye wo dometɔ ɖesiaɖe ƒe vovototo kple nɔnɔme vovovowo. Bu amadede ƒe kpɔɖeŋu be enye ɖoɖo bliboa (abe teƒewo ɖɔɖɔ to latitude/longitude zazã me ene) kple amadede ƒe teƒe be enye ɖoɖo ma ƒe nɔnɔmetata tɔxɛ aɖe (abe nuto aɖe koŋ ƒe anyigbatata tsitotsito si ƒe nɔnɔmetatawo sɔ pɛpɛpɛ ene).

Nu geɖee hea vovototo sia vɛ: ŋkuléleɖenuŋumɔ̃wo zãa RGB (additive) amadede esime agbalẽtamɔ̃wo zãa CMYK (subtractive) amadede; zi geɖe la, nukpɔkpɔwo ƒe didime kekena wu esiwo wota; screenwo naa kekeli dona esime agbalẽtatawo ɖenɛ fiana; eye ne womekpɔ amadedewo dzi nyuie o la, gɔmeɖeɖe aɖeke mele amadede ƒe teƒe vovovo siawo dome o. Tsɔ kpe ɖe eŋu la, pepa ƒomevi kpɔa ŋusẽ ɖe alesi amadedewo dzena le agbalẽtata me dzi vevie, eye zi geɖe la, pepa siwo ŋu womefa nu ɖo o la mewɔa amadede siwo me wodea nuɖuɖui fũu o wu pepa siwo le keklẽm. Wò ŋkuléleɖenuŋu ƒe dzidzedzekpɔkpɔ kple ICC ƒe nɔnɔmetatawo zazã na wò agbalẽtamɔ̃ kple pepa ƒe ƒuƒoƒo tɔxɛ ate ŋu aɖe vovototo siawo dzi akpɔtɔ ŋutɔ, togbɔ be vovototo aɖewo anɔ anyi ɣesiaɣi le dzɔdzɔmeŋusẽ ƒe vovototo vevi siwo le kekeli ƒe ɖeɖefiawo kple kekeli ƒe nɔnɔmetatawo dome ta.

Enɔ te ɖe wò dɔwɔwɔ kple nusiwo nàwɔ ƒe hiahiãwo dzi. sRGB nyo wu na nɔnɔmetata siwo woɖo ɖe web alo kpɔkpɔ le screenwo dzi le afisiafi. Adobe RGB nyo ŋutɔ na agbalẽtatadɔwo, enaa agbalẽtatadɔ si keke ta wu si sɔ kple agbalẽtata ƒe ŋutetewo nyuie wu. ProPhoto RGB nyo ŋutɔ na dɔnyala ƒe dɔwɔwɔ siwo me amadede ŋuti nyatakakawo takpɔkpɔ si sɔ gbɔ wu le vevie, vevietɔ ne wole dɔ wɔm kple RAW faɛlwo le 16-bit nɔnɔme me. Fotoɖela geɖe zãa mɔnu si wotsɔ tsaka: wotrɔa asi le wo ŋu le ProPhoto RGB alo Adobe RGB me, emegbe wotrɔa wo ɖe sRGB me hena web mamã. Ne èle foto ɖem le JPEG nɔnɔme me le fotoɖemɔ̃ me la, zi geɖe la, Adobe RGB nye tiatia nyuitɔ wu sRGB ne wò fotoɖemɔ̃a do alɔe, elabena edzraa amadede ŋuti nyatakaka geɖe ɖo hena asitɔtrɔ le eŋu emegbe. Gake ne èda RAW (wokafui be wòanyo wu) la, fotoɖemɔ̃a ƒe amadede ƒe teƒe ƒe ɖoɖoa kpɔa ŋusẽ ɖe JPEG ƒe ŋgɔdonya dzi ko ke menye RAW nyatakaka ŋutɔŋutɔ o.

Ne wole tɔtrɔm le amadede ƒe teƒewo dome la, ele be woagbugbɔ awɔ amadede siwo dze le teƒe si woɖo tae ƒe gamut godo to mɔnu aɖe si woyɔna be gamut mapping zazã me. Wokpɔa esia dzi to tameɖoɖowo gɔmeɖeɖe me: Nugɔmesese ƒe gɔmeɖeɖe kpɔa nukpɔkpɔ ƒe ƒomedodo siwo le amadedewo dome ta to vovototo bliboa tete ɖe edzi me; Relative Colorimetric léa amadede siwo le gamuts siaa me ɖe te eye wòɖea amadede siwo mele gamut o me ɖe amadede si te ɖe eŋu wu si woate ŋu agbugbɔ awɔ ŋu; Absolute Colorimetric hã sɔ gake etrɔna ɖe pepa ɣi hã ŋu; eye Saturation tsɔa amadede siwo le dzo dam la me léle ɖe asi ɖoa nɔƒe gbãtɔ wu alesi woawɔe wòade pɛpɛpɛ. Tiatia si nàwɔ be nàɖe tameɖoɖo gɔme la nɔ te ɖe emenyawo kple nusiwo nètsɔ ɖo nɔƒe gbãtɔ dzi. Le fotowo gome la, zi geɖe la, Perceptual ye naa nusiwo dzena abe dzɔdzɔmenuwo ene wu. Le nɔnɔmetata siwo ŋu adzɔnu ƒe amadede tɔxɛwo le gome la, zi geɖe la, Relative Colorimetric wɔa dɔ nyuie wu be wòakpɔ amadedeawo tututu ta le afisi wòanya wɔ le. Egbegbe amadededzikpɔkpɔ ƒe ɖoɖowo ate ŋu afia amadede siwo mesɔ o hafi atrɔ wo, si ana nàte ŋu awɔ asitɔtrɔ le amadede veviwo ŋu.

Monitor calibration nye gɔmeɖoanyi na amadededzikpɔkpɔ ƒe ɖoɖo ɖesiaɖe. Ne womekpɔ nukpɔkpɔ si woɖɔli o la, ke èle nyametsotso siwo ku ɖe ɖɔɖɔɖo ŋu wɔm le amadede ŋuti nyatakaka siwo mesɔ o dzi. Dodokpɔ trɔa wò ŋkuléleɖenuŋu ɖe nɔnɔme si wonya, si sɔ to ɖoɖo ɣi ƒe teƒe (zi geɖe la, D65/6500K), gamma (zi geɖe la, 2.2), kple keklẽ (zi geɖe la, 80-120 cd/m2), eye wòwɔa ICC ƒe nɔnɔmetata si dɔwɔɖoɖo siwo kpɔa amadede dzi zãna tsɔ ɖea amadedewo fiana pɛpɛpɛ. Le dɔnyala ƒe dɔwɔwɔ gome la, hardware calibration device le vevie eye ele be woawɔ recalibration ɣleti sia ɣleti. Amadededzidzenu siwo wozãna na nuƒlelawo gɔ̃ hã ate ŋu ana amadede ƒe nyateƒetoto nanyo ɖe edzi ŋutɔ ne wotsɔe sɔ kple nusiwo woɖena fiana siwo womeɖɔli o. Le dzidzedzekpɔkpɔ godo la, wò dɔwɔƒe hã le vevie—gli ɣi siwo medea akpa aɖeke dzi o, akaɖi si dzi wokpɔna, kple asaƒoƒo na kekeli tẽ le screen la dzi katã kpena ɖe ame ŋu wòkpɔa amadedewo nyuie wu. Le amadededɔ veviwo gome la, bu gadede ŋkuléleɖenuŋu si ƒe nyonyome de ŋgɔ si ƒe lolome keke ta, xɔtunuwo ƒe dzidzedzekpɔkpɔ ƒe ŋutetewo, kple ʋuƒo si xea mɔ na kekeli si ƒo xlãe ŋu kpɔ.

sRGB gakpɔtɔ nye dzidzenu na nyatakakadzraɖoƒe me nyatakakawo elabena ekpɔa egbɔ be nuteƒekpɔkpɔ si sɔ wu le mɔ̃ vovovowo kple web-browser vovovowo me. Togbɔ be egbegbe web-browserwo le asi kpem ɖe amadedewo dzi kpɔkpɔ kple vovototo siwo keke ta wu ŋu geɖe wu hã la, mɔ̃ kple web-browser geɖe mewɔe nenema haɖe o. Le dɔ siwo le ŋgɔ yim gome la, àteŋu awɔ ŋgɔyiyi vivivi to sRGB zazã abe gɔmedzedze ene esime nèle nunɔamesi siwo keke ta (zã CSS Color Module Level 4 ƒe nɔnɔmewo alo nɔnɔmetata siwo wode dzesii) na mɔ̃ siwo doa alɔ wo. CSS Color Module Level 4 to kpekpeɖeŋu nana display-p3, prophoto-rgb, kple amadede ƒe teƒe bubuwo to dɔwɔwɔwo abe color(display-p3 1 0.5 0) dzi, si na be nyatakakadzraɖoƒe dɔwɔlawo te ŋu ɖoa taɖodzinu na ɖeɖefia siwo keke ta wu evɔ womatsɔ woƒe sɔsɔ asa vɔe o. Be nàte ŋu awɔ ɖeka kple web-browser xoxowo nyuie wu la, lé nunɔamesiwo katã ƒe sRGB tɔ ɖe te eye nàzã feature detection atsɔ asubɔ nyatakaka gbogbo aɖewo na mɔ̃ siwo sɔ ko. Do wò aɖaŋuwo kpɔ ɣesiaɣi le mɔ̃ kple nyatakakadzraɖoƒe geɖe dzi be nàkpɔ egbɔ be woƒe dzedzeme sɔ na ezãlawo katã.

Amadede ƒe teƒewo kpɔa ŋusẽ ɖe nɔnɔmetatawo ƒe nutete kple faɛl ƒe lolome dzi vevie. Trɔtrɔ tso RGB yi YCbCr (le JPEG ƒe nutete me) ɖea mɔ na chroma subsampling, si ɖea faɛl ƒe lolome dzi kpɔtɔna to amadede ŋuti nyatakakawo dzraɖo ɖe nɔnɔme si bɔbɔ wu keklẽ ŋuti nyatakakawo me, eye wòwɔa amegbetɔ ƒe ŋku ƒe seselelãme geɖe wu ɖe kekeli ƒe nyatakakawo ŋu ŋudɔ. Teƒe siwo keke ta abe ProPhoto RGB ene hiã bit ƒe goglome si lolo wu (16-bit vs. 8-bit) be woaƒo asa na banding, si wɔnɛ be faɛl gãwo dona. Ne wole dzram ɖo ɖe nɔnɔmewo abe PNG siwo mezãa chroma subsampling o me la, amadede ƒe teƒea ŋutɔ mekpɔa ŋusẽ ɖe faɛl ƒe lolome dzi boo o, gake bit ƒe goglome siwo kɔkɔ wu ya kpɔa ŋusẽ ɖe edzi. JPEG faɛl siwo wodzra ɖo ɖe Adobe RGB alo ProPhoto RGB me mezãa nudzraɖoƒe geɖe wu sRGB tɔ le dzɔdzɔme nu le nyonyome ƒe ɖoɖo ɖeka ma ke me o, gake ele be amadede ƒe nɔnɔmetata si wotsɔ de eme nanɔ wo me hafi woaɖee afia nyuie, atsɔ akpe ɖe faɛl ƒe lolome ŋu vie. Be woateŋu awɔ nutete nyuie wu le dɔdɔ ƒe nɔnɔmewo me la, tɔtrɔ ɖe 8-bit sRGB alo YCbCr ŋu kple subsampling si sɔ zi geɖe naa faɛl ƒe lolome kple nyonyome si wokpɔna ƒe dadasɔ nyuitɔ kekeake.

Bit ƒe goglome kple amadede ƒe teƒe nye nukpɔsusu siwo do ƒome kple wo nɔewo siwo kpɔa ŋusẽ ɖe nɔnɔmetata ƒe nyonyome dzi. Bit ƒe goglome fia bit ƒe xexlẽme si wozãna tsɔ tsi tre ɖi na amadede ƒe mɔnu ɖesiaɖe, si fiaa amadede ƒe asixɔxɔ vovovo agbɔsɔsɔme si woate ŋu atsi tre ɖi na. Togbɔ be amadede ƒe teƒe ɖea amadedewo ƒe didime (gamut) gɔme hã la, bit ƒe goglome ye afia alesi woama dometsotso ma nyuie. Zi geɖe la, amadede ƒe teƒe siwo keke wu abe ProPhoto RGB ene hiãa bit ƒe goglome si kɔkɔ wu be woaƒo asa na banding kple posterization. Esia le alea elabena ele be asixɔxɔ vovovoawo ƒe xexlẽme ma ke nakeke ɖe amadede ƒe didime si lolo wu me, si awɔ “afɔɖeɖe” gãwo le amadede siwo te ɖe wo nɔewo ŋu dome. Le kpɔɖeŋu me, 8-bit encoding naa dzidzenu 256 le mɔ̃ ɖesiaɖe dzi, si zi geɖe la, esɔ gbɔ na sRGB gake mesɔ gbɔ na ProPhoto RGB o. Esia tae dɔnyala bibiwo ƒe dɔwɔwɔ ƒe ɖoɖowo zãa 16-bit le mɔ̃ ɖesiaɖe dzi (65,536 dzidzenuwo) zi geɖe ne wole dɔ wɔm le teƒe siwo keke ta. Nenema ke HDR me nyawo hiã bit ƒe goglome si lolo wu (10-bit alo 12-bit) be woatsɔ atsi tre ɖi na eƒe keklẽ ƒe didime si keke ta la nyuie. Amadede ƒe teƒe kple bit ƒe goglome ƒe ƒuƒoƒoe afia amadede vovovo siwo woate ŋu aɖe afia le nɔnɔmetata me ƒe xexlẽme bliboa.