What is the difference between navy blue, midnight blue and indigo?

Navy blue is an almost black blue. If you started with blue and added black you'd approach navy.

Indigo is more purple -- a violet blue. If you started with purple and added blue you'd start getting close to indigo.

Midnight blue falls somewhere in between. There are a lot of different shades that can be called midnight.

What about this shade of blue:



What shade of blue would you call this? I was looking for an "evil" shade of blue to use. I had a dark blue and added a purplish tint to it. It's like a blackish blue.

Would you call this midnight blue?

Boomer- That reminds me of a very old joke.

Did you hear the one about the cow who swallowed a can of violet paint, and mooed indigo???


(This reference is for those who are not old enough to understand the "humor.")

How very PUNNY of you.

I would call that Prussian Blue.

But it's important to remember that every computer monitor doesn't "see"

Midnight blue comes in many shades. I consider it midnight.

Anyway, would you say my shade of blue is "evil"?

It's blackish blue.

I don't really associate colors with good and evil so I really can't help you there.

There is a symbolism of colours and there you can find what a colour means. It can vary from colture to culture. Blue as rule has nothing to do with evil.
Blue is the color of spirituality, intuition, inspiration and inner peace. It is also associated with sadness and depression (the "blues"). In healing blue is used for cooling and calming, both physically and mentally. In the aura blue indicates serenity, contentment and spiritual development.
Black would come closest to evil. Black is the absence of color. It represents the unconscious and mystery. Its visualization can help promote deep meditation. Black also stands for evil (eg black magic). In the aura it signifies some kind of blockage or something being hidden.

Color names are not (that I know of) all that official.
Some showed up decades ago on crayola crayons - such as prussian blue:



But crayola changed the name to midnight blue -
see here:
http://en.wikipedia.org/wiki/List_of_Crayola_crayon_colors

But this link backs up Boomerang's take on prussian blue -
http://www.webexhibits.org/pigments/indiv/overview/prussblue.html

Or, it's a white nationalist pop teen duo, according to wiki -
http://en.wikipedia.org/wiki/Prussian_Blue

One of my favorite paint colors is Winsor Newton's oil color - Indigo.
I don't think of purple when I look at that:
http://www.cheapjoes.com/prod/WNPO322-37/

On the other hand, there is the plant, indigo:

which has what I would call a purpleish-pink colored blossom:

and maybe I haven't seen examples of a purple-y indigo.

If you have followed paint chips in home improvement stores over the years, you'll have a sense of the wackiness involved in color naming - maybe in another life I'll get hired as a paint namer.
But - the ones I'll usually believe in started with a pigment name and are pretty standard.

I forgot to remark on navy (or look up references about it). It was my mother's favorite color and remains one of mine, but my memory of colors that were called navy vary a lot, from a deep blue black, to sort of blue black.

I suppose it had something to do with naval uniform colors - which I trust were chosen to reference the sea - then picked up by producers of fabrics.
So - wiki -
http://en.wikipedia.org/wiki/Navy_blue
there ya go, nice visual.

Indigo is a dark blue-violet, not just any value of blue-violet.

Midnight blue is not a recognized artist's paint colour, but I'm suspecting it could be darker than navy. You have have several shades of navy blue, for example, and the midnight suggests dark as dark. Just my take on it.

No, I would not call that a midnight blue. Try adding way more black.

I can tell you, as an artist, that warm or hot colors, like red, or dark murky colors, like midnight blue, are usually associated with evil.

Indigo was originally grown in the colonies and sold to the British Navy to dye uniforms. Seems likely, then, than indigo and navy blue were once identical. Nomenclature may have changed in the past four centuries or so.

Prussian blue and midnight blue are the same:

http://en.wikipedia.org/wiki/List_of_Crayola_crayon_colors
http://en.wikipedia.org/wiki/Prussian_blue

I already told you that.