Photoshop :: How To Make A Color Spectrum

I need to do a job which consist of a high-quality print of 14cm high x 1100cm long os the color pectrum. the color spectrum order would be: black -> purple -> dark blue -> light blue -> dark green -> light green -> yellow -> orange -> red -> and again dark purple.

Like a big long gradient line from the spectrum as we see in the colour pallete.

I do't have a lcue how to do this, can someone help me in a detail tutorial?

Ps.: I have Photoshop CS3