Hindu gods, most notably, Shiva, Krishna, Vishnu, Kali, are depicted as blue colored beings. But they are also depicted with many different skin colors, some looking more natural than others.
Is there any textual evidence regarding the color of the skin of the gods? Or were these ideas of skin color made up by the illustrator?
Short answer: Color signifies the property of the God's character. See this Mantra reference
Long answer: Honestly, anything I write here would be a duplicate of this excellent answer on Hinduism.SE: Why are Hindu Gods colored?.
I've made this answer community wiki as the content is not mine, so I don't deserve any rep from it. But at least this can be marked as accepted now. Here is the full text as written by @Creator in case it gets edited or removed:
Color signifies the property of the God's character
Shiva is karpur Gaur- i.e. white as a camphor, because he is sinless and is totally nirlipta(not affected by samsara or worldly habits or wealth) he is always covered in white Bhasma (ashes which come out of his own agni stambha form [refer :Linga Purana]).Talking about Rama he is light-blue colored signifying the calmness and politeness also the maryada(always being within human limits) in fact in our body the 5th chakra (from root chakra or mooladhar chakra) Throat Chakra is light-blue coloured (see this for more info on Throat Chakra or Vishudha chakra). It is said that after reaching this chakra kundalini dosen't goes down or one does not degrades (spritually) that's why lord Rama is taken as ideal human or god.
Dark Blue color of lord Krishna Depicts the milan of Shiva and Hari it means the Sandhya Kal (Evening Time) where day meets night (day-shiva night-hari(dark blue)). Also Narayana's core character is regarded as Krishna that's why he is depicted Dark Blue same as narayana.The Anjana Chakra (Third-Eye) has same color as lord Krishna (see this for more info)
अतुलितबलधामं हेमशैलाभदेहं
दनुजवनकृशानुं ज्ञानिनामग्रगण्यम् ।
सकलगुणनिधानं वानराणामधीशं
रघुपतिप्रियभक्तं वातात्मजं नमामि ॥This mantra from SunderKand of Ramayana depicts Characteristics of lord Hanuman. Here Haemshalbdeham means 'body like
Golden Mountain'. The golden color of his body depicts that he is so beautiful and powerful (full of good aura) that his body has become golden also because of ram Bhakti or chanting of continuous ram name.At Last Gauri as name depicts is white as her husband Mahadev Lord Shiva, because she has unified with him she posses same character as Mahadev Lord Shiva.
In humans it is the varna which is specified in jyotishya (Astrology) and the patrika of a person this depicts the color of human child when he is born and this affects its characterstics (do not consider it racism).According to this varna the gana is found.
Read this if you want more details on colour and their significance.
As with anything in Hinduism, there is an overabundance of sources rather than a lack of one.
Taking examples from just one text; Abirami Andhadhi, a poem on Abirami which is another name for Parvati (or Gauri, the consort of Shiva as mentioned in the other answer):
The very first stanza of the poem describes the various similes to the red colour of the Goddess: the rising sun in the morning (உதிக்கின்ற செங்கதிர்), the red kumkum kept on the forehead (உச்சித்திலகம்), a ruby stone (மாணிக்கம்), the flower of pomegranate (மாதுளம்போது), all these are given as examples of how her skin looks.
But then, a few verses later (v:15), the poem compares her to a "green parrot" (பைங்கிளியே ), and then later (v:70) calls her someone who appears in a "green that denotes a joyful land" (மண் களிக்கும் பச்சை வண்ணமும் ஆகி ... தோன்றிய எம்பெருமாட்டி).
The best of all is verse 21 though, which calls her "பிங்கலை நீலி செய்யாள் வெளியாள் பசும்பெண்கொடி":
* பிங்கலை refers to a yellow or golden-skinned person
* நீலி directly translates to "blue-coloured"
* செய்யாள் translates to "red-coloured"
* வெளியாள் translates to "white-coloured"
* பசும் பெண் கொடி calls her "green coloured
All within a single line!
And this poem is not a special case either: most of these references go back to older texts (eg. Lalitha Sahasra Nama or Sankara's Soundarya Lahari), which too assign varying colours to the Goddess.
And this isn't limited to Goddess Parvati too. Shiva gets white, black or blue skin in different places, Vishnu goes through black, blue, red and green in different texts, and so on. One of Vishnu's avatars, Krishna, actually directly translates to "the dark-skinned one", but even he usually gets blue-skin in illustrations, as the question mentions. (My theory is that this is actually linguistic misunderstanding: the original Sanskrit calls him "neela" coloured, which back then refered to any dark colour, black or dark blue or dark green; by the time of these illustrations though, the common languages had "neela" meaning just blue.)
The reasons for this can be given from two viewpoints:
from a historical view, the reason there's so much variation is (a) these texts were generally written by poets in the Bhakthi tradition, which is all about emotion and personal connection with God rather than analytical accuracy (b) Hinduism has absorbed various local beliefs through time, and allowed them all place within itself, turning those regional Gods into forms of the original Hindu Gods (so for eg. when Maariyamma மாரியம்மா a Tamil regional Goddess was taken in as a form of Goddess Parvati, Parvati acquired her dark skin as one of her colours).
from a philosophical view, it is a constant reminder to not get attached to the form of the God, that names and forms (Naama-Roopa) - even those of Gods - are only products of Maya, and the Truth is beyond such limitations.
In essence God is formless, colourless, He is in everything and everything is with in Him. ( Refer to stanza 24 in Phalashruti) He lives in everything ( Search for 'Vyasa Uvacha:- Vasanad Vasudevasya vasitham bhuvana trayam, Sarva bhutha nivasosi vasudeva namosthuthe. Sri Vasudeva namosthuthe om nama ithi')
Vishnu Sahasranaam Stotra : This stotra is the stuti of Lord Krishna made Shri Bhismacharya for advising 'How to Rule the kingdom, what are the ideals which one should follow while ruling the kingdom? etc ' to the would be King Yudhistir, after the famous Mahabharata Epic war in the history which was won by Pandavas. This stuti comes under Mahabharata book in 11 parva or you can also say 11 chapter.
For the colors of hindu deities here is the link
I know you might not like my answer below but here is what I have observed after reading few books or puranas:
Basically, the images which we see today of our respected Gods, are trying to say something, but what do we understand? say for example I want to show in an draw a person who is calm, knowledgeable, leader, good at warfare, good at yoga or meditation or say beautiful then in previous ages of mankind as there was no digital photography which can rake live photos or whatever so what the intelligent people did is they gave symbols, these symbols are like anagrams or coded language it goes like :
Calmness : shown by slight smile on their face.
Knowledge: As we all know Lotus is a symbol of knowledge, I know this as my school had a batch which had lotus on it and motto line as 'knowledge is power'.
Leader: showing lots of other people may be gods in this case facing towards their leader. thats a sign of leadership.
Good at warefare: showing weapons in thier hands especially.
Good at Yoga / is in Meditation: 3/4 th of his / her eyes are closed. only 1/4 th open.
Beautiful: Many ways to show this, how about showing a slim body structure etc.
And similarly the colors as well say a lot of things related to their respective characteristics i.e
Red = Anger/ war/ destruction with respect to preserving the good and destruction or rooting out the bad from society or community.
Blue : Attractive, loving, caring, peaceful nature.
White: Agreeing to 1st answer in post Nirlipta. It also shows Pure-ness.
Such types of meanings can be derived from the pictures, I will try to search and add supporting links for the last paragraph.
The Sanskrit scriptures mentions the colour of the divine entities.
Sri Hari was first golden colour, then white, then sky blue and dark. Siva is white
Durga/Lalitha - red in colour (raktha varna) golden hued (swarn Ambika) Parvathy/Girija green in colour
In essence God is formless, colourless, He is in everything and everything is with in Him. He lives in everything (Sarva bhootha nivaso asi Vasudeva namosthuthe)
I found an answer with regards to body colours of Lord Krishna here - http://www.iskcondesiretree.com/page/six-categories-of-avatars
When He descends into the material world during different "yugas" or ages, He assumes 4 main colours. The Four yugas (Ages) come in cycles and are as follows:
In Srimad Bhagavatam (compiled 5000 years ago), there is this verse:
asan varnas trayo hy asya / grhnato ‘nuyugam tanuh / suklo raktas tatha pita / idanim krishnatam gatah
*
“Krishna appears as an incarnation in every millennium. In the past, He assumed three different colors - white, red and yellow - and now he has appeared in a blackish color.” - Srimad Bhagavatam Canto 10, Chapter 8, Verse 13
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The colours per yuga are as follows:
In the Satya yuga, He appeared as Sage Kardama Muni in a white complexion to establish meditation as the process for self-realization.
In the Treta yuga, He appeared with a red complexion to Brahma to establish fire sacrifice as the process for self-realization.
In the Dvapara yuga, a dark avatara (Krishna) appeared as the son of Devaki to establish temple worship as the process for self-realization.
In the Kali yuga, a Yellow avatara appeared (Chaitanya Mahaprabhu) as the son of Mother Sachi to establish the chanting of the holy names (nama-sankirtana) as the process for self-realization.
Hope this helps :)
