TIF stores all the available color information as it was saved (or converted from RAW) by your camera.
What JPG does, is try to compress (or reduce) the color information by making average color calculations of every pixel and its adjacent pixels, throwing out as much non-average color pixels as possible while trying to visibly retain the same look.
At first sight, you may not see the difference. That difference becomes apparent when you repeatedly save a file. The TIF file will always retain its full color information; the JPG file will throw out color information every time you save it. After saving the same file five or more times as a TIF and as a JPG, you will see the difference.
That's why it's a good idea to always save (a copy of) the original file in TIF format (or another lossless format) as your starting point.

Another result of this is that JPGs or generally used for the web, while for four-color (CMYK) process printing TIF files will be used.

We do not see things as they are. ǝɹɐ ǝʍ sɐ sƃuıɥʇ ǝǝs ǝʍ