Color space refers to the range of colors that a digital camera can process, a monitor can display or a printer can print.
If you have a good digital compact or a digital SLR, you may have come across the the color space setting which is normally an option between Adobe RGB or sRGB.
So how do we know which one to select?
First, lets talk a bit about RGB and CMYK color models.
RGB is an additive color mixing model- this is how your color computer monitor generates all the colors on the screen- by adding Red, Green or Blue light. This is different from how you mix and make different colors when you paint which is referred to subtractive mixing.
Now that we know that RGB color model is used by our digital cameras to capture an image and output it to the LCD screen and CMYK is used by printers while printing out that image, lets go back to our original question.
sRGB or Adobe RGB?
sRGB is a standard color space (or color profile) developed by HP and Microsoft for the internet in 1996. Adobe RGB was developed by Adobe in 1998 with the intent of achieving most of the colors in CMYK model using the RGB model. in non-geek speak, it means that an image that uses Adobe RGB color space can show and print a greater range or colors (mostly in the cooler cyan-greens) compared to sRGB. Most web browsers ignore color profiles so any image that uses Adobe RGB will look washed out when viewed in a browser compared to how it looks in Adobe Photoshop or any application that support color profiles.
To share photographs or a portfolio over the web, it's always better to stick with sRGB. It's possible to convert color profile so if you have the camera set for Adobe RGB, you can always email or post a picture on Facebook after converting it to sRGB. Alternatively, you could shoot in RAW and you don't have to worry about the camera applying any color profiles in the output.