The first thing you should know (and accept as something as inevitable as gas prices never going down) is that the colors of your website will differ from computer to computer, from monitor to monitor.
Let’s compare this with the much more familiar task of painting your room. You buy a can of paint made by company A, run out of it with half your wall still unfinished, then run back to the shop, where only cans made by company B are left; you buy one, take it home, paint the remaining half — only to find out that the two halves differ. We all know why it is so: the tone of the color is the result of mixing together different elements, and as soon as those elements (and surrounding variables) differ, even slightly, you get a different result.
Now, in (computer) monitor terms, color is streams of electrons striking phosphors. That is, inside your monitor a beam of electrons runs through the box, then strikes the inside of the glass which is covered by three different phosphors that emit red, green, and blue light, respectively. By varying the strength of the electron beam, we can make the phosphors emit more or less red, green, and blue light, the combination of which produces different colors.
As you may start to guess, the phosphors used in different monitors are of different types (there are at least five different types in common use). Phosphors also, to a great extent, change with their age: thus, next month the same colors on your same monitor will look different from what you see today. Throw in the differences due to specific circuitry, LCD or CRT, strength of magnetic field surrounding your monitor, lightness and contrast settings (something you may have played with, for better or worse), and it will become very clear that there is no way you can expect identical colors from two monitors, even of the same model, even bought on the same day.
Then again, without going into why and how, color also depends on the platform (PC or Mac or Linux), on the browser and its settings (which 99% of us leave at default, actually a sad, sad thing), on the surrounding light source (daylight or tungsten or candle ), etc.
Now, having said that, what about huge differences, for instance, when you see black turning into grey, or blue into cyan, or ivory into plain white? If the matching colors exactly is a utopia, if one can forget about matching all six numbers of your SuperLotto draw, can one at least make three or four of them right? Can you make your monitor, if not tell the truth and nothing but the truth (about the colors), then at least not lie unabashedly?
Yes, it’ possible, and it takes only five to ten minutes once every three or four months. That’s less time than you spend changing oil for your car, and it costs nothing; so, please, make a gift for your eyes and aesthetic senses, read and comply:
Something very, very simple: