Colors can be presented in many different ways and is a medium to visually simulate and evoke emotional association with your work. Pehaps this is what makes artistry so fun and personal.
Note: keep in mind that variations in computer monitors and graphics card may prevent you from seeing colors of fabric in it's true life color. All photos we take in our studio of products are taken using daylight lighting (approx 5200K). There are instruments graphic artists and publication professionals use to calibrate their monitors to most closely approximate true color.
There are many color wheels ranging from the most basic overlapping circle charts to the complex, no one is better then the other, it all depends on which one you feel is most helpful in your color matching and coordianting for your project as a fibre artist.
Here at Kiki Quilts we have adoped the color wheel located immediately below. You will note that our "find fabric by color" section arranges the primary color of the fabric in these same color wedges. You may also want to reference complimentary colors entry in Kiki-pedia for those color critical design projects.
Other examples of color wheels: