Kukhona ukuhlolwa okuhlukahlukene ukuze kutholwe ubumpumputhe bemibala, ukukhubazeka kokubona okuthinta ukuhlukaniswa kwemibala, futhi kuthinta u-8% wabantu besilisa uma kuqhathaniswa no-0,45% wabesifazane kuphela. Okwaziwa kakhulu kulezi zivivinyo oka-Ishihara.

Ubumpumputhe bemibala (eqanjwe ngesazi sefiziksi esiyiNgisi sekhulunyaka le-18 uJohn Dalton) yinkinga yokubona ethinta umbono wemibala. Isifo sofuzo: kungenxa yokungajwayelekile (ukungabikho noma ukuguquka kwesimo) ezakhini zofuzo ezifaka umbala obomvu noluhlaza, zombili ezitholakala ku-X chromosome, noma kuzakhi zofuzo ezifaka ikhodi eluhlaza okwesibhakabhaka, ku-chromosome 7 Ngakho-ke ubumpumputhe bemibala buwufuzo, ngoba umzali oyedwa noma bobabili bangadlulisela lesi sici sofuzo. Kuvame kakhulu emadodeni ngoba athwala ama-X chromosome amabili. Kuyaqabukela, ubumpumputhe bemibala bube okwesibili kusifo samehlo noma isifo esijwayelekile (isifo sikashukela).

Ngokuya ngokungavamile kofuzo, kunezinhlobo ezahlukene zokungaboni umbala:

I-Monochromatism (noma i-chromatism): umuntu akahlukanisi noma yimuphi umbala ngakho-ke ubona kuphela okumnyama, okumhlophe nemithunzi empunga. Lokhu okudidayo akuvamile kakhulu.

I-dichromie : enye yezakhi zofuzo, ngakho-ke enye yemibala, ayikho.

• uma kuyi-gene encoding red, umuntu u-protanopic: ubona kuphela okuluhlaza okwesibhakabhaka nokuluhlaza;
• uma kuyi-gene encoding green, umuntu u-deuteranopic: ubona kuphela okuluhlaza okwesibhakabhaka nokuluhlaza;
• uma kuwuphawu lofuzo oluluhlaza okwesibhakabhaka, umuntu une-tritanopic: ubona okubomvu nokuluhlaza kuphela.

I-trichomatie engavamile : enye yezakhi zofuzo ishintshiwe, umbono wombala ngakho-ke ushintshiwe.

• uma kuyi-gene encoding red, umuntu une-protanormal: banobunzima bokubona okubomvu;
• uma kuyi-gene coding yohlaza, umuntu u-deuteranormal: unobunzima bokubona okuluhlaza;
• uma kuwuhlobo lwekhodi eluhlaza okwesibhakabhaka, umuntu une-tritanormal: unobunzima bokubona okuluhlaza okwesibhakabhaka.

Ukuze uthole lokhu okudidayo, kukhona ukuhlola okuhlukahlukene. Nazi eziyinhloko:

• ukuhlolwa kwe-Ishihara, eqanjwe ngomdali wayo waseJapane uShinobu Ishihara (1879-1963), isetshenziswa kakhulu. Ivumela ukutholwa kokushoda kokubona okubomvu nokuluhlaza (i-protanopia, i-protanomaly, i-deuteranopia, i-deuteranomaly). Iza ngendlela yamapuleti angama-38 okuthiwa yi-pseudo-isochromatic: embuthanweni kukhona amachashazi anobukhulu obuhlukene nemibala, okuvela kuyo, kumuntu obona ngokujwayelekile (i-trichomate), inombolo. Lezi zingcwecwe zethulwa ngokulandelana okuqondile esigulini, okufanele sisho inombolo esiyehlukanisayo noma cha.
• le test "ukubona kombala kwenza kwaba lula" inguqulo yezingane yokuhlolwa kwe-pseudo-isochromatic. Esikhundleni sezibalo, lezi yizimo ezingahlukaniswa emabhodini.
• Panel D15 kanye nokuhlolwa kwe-Farnsworth-Munsell I-100-hue, eyathuthukiswa ngu-Dean Farnsworth ngo-1943, iza ngendlela yamachashazi amancane anombala ukuze abekwe ngendlela efanele.
• Ukuhlolwa kukaHolmgren isebenzisa ama-skeins anemibala yoboya. Ezintathu zazo zisebenza njengereferensi: i-skein A ngokuluhlaza, B ngokunsomi no-C ngokubomvu. Isiguli kufanele sikhethe phakathi kwamanye ama-skein angu-40 angu-10 asondelene nombala A, 5 ukuya ku-B bese kuba ngu-5 kuya ku-C. Ngemva kwalokho kumelwe azihlukanise ngokwezigaba zombala. Lokhu kuhlolwa kusetshenziselwa ikakhulukazi ukuhlonza ubumpumputhe bombala kumatilosi, abasebenzi bezitimela kanye nabasemoyeni, ubungcweti obunqatshelwe abantu abangaboni umbala ngenxa yokusetshenziswa kwezimpawu ezibomvu neziluhlaza.
• ukuhlolwa kwe-Verriest, eyadalwa ngo-1981, ihloselwe izingane. ifika ngendlela yamathokheni anemibala ukuze ihlangane, njenge-domino.
• ngivivinye uPease no-Allen (1988) iphinde ihloselwe izingane. Iza ngesimo samanxande anemibala engu-4 (omhlophe, obomvu, oluhlaza okotshani noluhlaza okwesibhakabhaka) nesikwele esincane sombala ohlukile ekhoneni elilodwa, phezulu kunxande. Ingane kufanele ihlukanise imibala.

Lezi zivivinyo zenziwa uma kwenzeka izinsolo zokungaboni umbala, "emikhayeni" yabantu abangaboni umbala noma lapho kuqashelwa imisebenzi ethile (ikakhulukazi imisebenzi yezokuthutha zomphakathi).

Alikho ikhambi lokungaboni umbala, okungaba kubi kakhulu noma kuthuthuke ngokuhamba kweminyaka. Futhi abantu abanobumpumputhe bemibala ngokuvamile bazwana kakhulu nalokhu kungavamile.

Kukhona, yiqiniso, izibuko, ngisho namalensi akhethekile, anezihlungi zombala zokushintsha i-spectrum yombala, kodwa ngokuvamile asetshenziswa kancane.