These are not always true. Take for instance the case of Blue and Green. When you look up the sky you often see the foliage of trees in the backdrop of blue sky and you like it. Whenever you go for color combinations always seek inspiration from nature, I can tell you people tend to accept the color combinations found in nature.

Certain colors are said not to go together becuase people who have various forms of color blindness can't see them. Here is some information regarding that.

http://msdn.microsoft.com/en-us/library/bb263953.aspx

In the sense of red and green, most people would say to avoid that because it is too christmasy, but in actuality red and green compliment each other in the same way orange and blue do.

In my opinion this never counts because by saying blue or green which shade of these colors you use, everything depends on that.

Say if i use light green with a turquoise shade of blue than it will surely look good. Even Red and green could look good together if they are used well after doing research on their shades.

But still when there are lots of other good colors don't go so deep.

It depends on what you are trying to do.

GENERAL:

If you are creating a picture, there is no real problem with any color combinations.

There are some elitists who want to force their aesthetics on others. They don't like certain color combinations. Some of my personal dislikes are:

red, yellow, and violet, without green
red, yellow, and cyan, without green
red, yellow, and blue, without green
magenta, cream, and powder blue
lavender, peach, and powder blue

But personal dislikes are not universal. Every person has different color combinations he dislikes. Ignore personal dislikes.

There are others who say that color combinations at certain angles on a color wheel are bad. But their science is bad, because they are using color wheels based on the erroneous red-yellow-blue primaries.

TEXT:

If you have one color as the text and the other color as the background, then there are a lot of restrictions, because the text becomes very hard to read in certain cases:

- If the grayscale level is the same, the text disappears on a monochrome monitor.

- The human eye has a lower resolution for color differences than it has for differences in lightness. This makes small colored characters hard to read on a colored background, especially on low resolution monitors.

Color blindness makes certain colors appear to be identical:

- Red, orange, yellow, and green all look the same to a green-blind (deuteranopic) person.

- Red, black, and brown all look the same to a red-blind (protanopic) person. So do green and yellow, as well as magenta and blue.

- Browns and blues look the same to a blue-blind (tritanopic) person.

- Yellows look orange in deuteranomaly.

- Yellows look yellow-green in protanomaly.

I’ve read around that color theorists and designers in fashion or computer graphics have coined phrases based around what colors shouldn’t go together. A couple of them are:”Red and Green Should Not Be Seen” and “Blue and Green Should Never Be Seen without Something in Between”. I am a newbie so I’m not sure if this applies in all cases any opinions on this?

Why dont you read the replies from the first post you made with the exact same question?

http://www.daniweb.com/forums/thread140442.html

hi,
thank you, I just can't find the post, so I have to post again... that's why I post another one, thanks, alot answers provided by you guys!!!
I'm appreciated!

hi,
thanks people,
I just post the same post on the site as I couldn't find the original one which means this one, not for HI2Japan's help, I must waste much breath.
I found the link above is very useful, really learnt alot, about color combination, my personal view is combine bright color with bright ones, like red with yellow, something like that, I don't know, but i'll spend time on it.
thank you guys!!

when thinking of what colours you should use you should look into colour blindness as someone already pointed out. from the top of my head i can think of two different types of colour blindness which are protanopia which deals with reds and greens and deutanopia which i think is blues and purples. colour blindness effects how the user will see different shades of colours.

i know from experience that colour blind people can get some shades of gray and blues confused and some say they cannot see the colour purple. so what looks good to you might not be good for people who are colour blind.