Hii…myself Chitu ,the badass 😎😎creature on earth ,Any doubt ?? That was my fb profile picture …I wanna update this on Insta also . But it seems too ‘colourful’ .
– yes …but why !!
I think this is because of chromatic abberation .( Colour overlapped on colour )
– what is that fellow ….
Haa.haa …don’t know …then listen to me .
Our colourful world mainly consist of 7 core colours . Mixture of these core colours makes it white .
What !!! Is it true…?
Shut up! …or sir Newton will through his colour wheel on you .
Newton’s colour wheel
When u see a red rose 🌹. …u know it absorbs all the colours except the red colour . Red colour refelcts and u see the rose red ….and u fool made it symbol of love !! 🥴
Violet , Indigo ,Blue,Green , Yellow, Orange ,Red are the main core colours .And each colour has its own particular wavelength. Red has the highest wavelength and violet has the lowest.
The cone cells of retina are most important for colour vision . The S M L types of cone cells catch every wavelength of light so that u can enjoy the colours of the world .
But the refractive surfaces of eye (cornea and lens mainly) consist of an amount of refractive index . And for a particular refractive index …wavelength is directly proportional to focal length .
So that When normal day light pass through our eye’ s refractive surfaces ….red makes focal point further than orange yellow green blue indigo and violet .
Longitudinal chromatic abberation
Human eye ,that suffers from Longitudinal Chromatic abberation have a facility that low light intensity activates rod cell and no colour discrimination needed , and we can reduce artificially by using low dispersing glasses ( fluorite glass ) .
For this type of abberation our eye becomes slightly myopic for green light and hyperopic for red light .
Yellow , the mid wavelength colour perfectly focuses on retina.
predominance of Yellow spectre on retina under day light
Famous chapri boys wore yellow glasses to minimise chromatic abberation .
There is another type of abberation named lateral abberation ( colours after dispersion meets on a vertical line rather than optical axis )
Lateral abberation
…. Is that abberation fellow totally useless
No ….. Ofcourse not . Do u know that the duochrome test is totally besed on this phenomenon.
Duochrome test – we use green and red background with snellen letter to detect over correction and under correction .
If a patient is overplused or underminused ..then it will shift the red light to focus in retina and the red background appears more clearer . Use minus to similarize the 2 background s.
Overplused / underminused
If the patient is underplused or overminused then it will shift the green light to focus on retina ,and the green background appears clearer and red becomes fuzzy . Use plus to similarize 2 background s.
Underplused/ overminus
How can I fix chromatic abberation – there are few modes of correction of chromatic abberation. One can use a glass made up of low dispersion glass ( crown glass) patched up with high diapersion glass( flint glass ) to reduce chromatic abberation. This lenses are called achromatic lens .
Low dispersion glass made up of fluorite are also popular now a days
special facts – In night time ,under low illumination most of the blue and violet wavelength focuses on retina and that turns our eyes slightly myopic . That is known as night myopia .
And last word from chitu …use yellow glasses to see my dp perfectly and if not then …………
