One area of confusion for many photographers is what color space to use when shooting: Adobe RGB or sRGB.
First, what does RGB mean?
RGB stands for Red, Green, Blue (the colors on a monitor.) In contrast there CMYK or Cyan, Magenta, Yellow, and Black (the colors used in off set printing such as magazines.) Note: most commercial professional photography labs will convert your images to sRGB because the printers are set up this way.
What is the difference between sRGB and Adobe RGB?
Basically sRGB is a Standard Red Green Blue color space set up by HP and Microsoft for use on monitors and the internet. It is a generalized standardized color space that the average person sees on their computer monitor. Adobe RGB was set up in 1998 by Adobe Systems to encompass most of the colors seen through CMYK printers as translated through the RGB color space. The major difference is that Adobe RGB has a much wider range of colors and hence a wider gamut mostly seen in the cyan-green hues.
How will they look on your monitor?
Adobe RGB will look desaturated and your skin tones may look ashy while sRGB will look vibrant and clear. When you export your files to view on the web, make sure you export them in sRGB mode.
How should you set your camera?
You are able to set your camera to either RGB or Adobe RGB mode. If you are in sRGB mode the image file naming will stay the same (ie: IMG_0001) if you switch to Adobe RGB it will be denoted with an underscore in place of the first letter (ie: _MG_0001.) Which one should you choose? If you are shooting large JPEG you will want to shoot in Adobe RGB since you will get the widest gamut. If you are shooting RAW it does not matter because ALL the file information is there and you will decide in the post production which color space to export the files. It really does not matter either way if you are shooting in RAW however if you are shooting RAW + small JPEG then you might want to shoot in sRGB for the JPEGs. Many shooters will shoot RAW + small JPEG to do quick previews of the shots on a laptop at the reception.
How should I export my images for print?
The RAW files will only be exported in Adobe RGB if your printer specifies that they need it that way. For wedding photographers this is really only necessary when you are going to have an image published in a magazine or book. As noted above, most commercial labs for photographic printing will recommend you send them in sRGB, however if you send them an Adobe RGB file they will just convert it to sRGB anyway. Why? This might frusterate you to no end because all that extra color information is being stripped and thrown away. The simple reason is, their printers are not set up the way CMYK off set printers are. You will not notice a difference at all when it comes to shooting people. If, however, you are shooting mostly landscapes this may effect you because it is the blues and greens that are being clipped. If this is the case for you, you will want to research the various labs and find the proper output for you. It may mean finding a lab that supports ProPhoto color space which is even wider than Adobe RGB. [yes, there is a third and even better option for you dynamic range junkies so you better do your research!]
Here is a book to look into for further understanding: Real World Color Management by Brude Fraser