Magenta Spot Color

I'm trying to make a .tif of an image (http://storage1.morguefile.com/images/storage/m/mconnors/lowrez/P8095437.JPG) with only a magenta spot color. I'm running a Mac OSX with Photoshop 7.0 and QuarkXPress 7.2, and so I tried deleting the cyan and yellow channels in photoshop. This forces me to save the Photoshop image as a DCS 2.0, thus incompatible with Quark (has to be in a .tif). This image is ideal, however, but I can't seem to make it work out.

Making a monotone of the image makes the entire image magenta (and duotone isn't much better), but I'm trying to have the film reel tape as magenta and the top part of the tape be black.

The hue/saturation was very easy to make the tape into magenta from red, but printing is another issue that I am not quite familiar with. Any help much appreciated.

What I would do is this:-

Duplicate the layer
Desaturate the bottom layer
Get the magenta colour you want on the top layer using the Hue/Saturation method you describe
Use a layer mask on the top layer to knock out all the magenta areas you don't want
Save as a Tif

Hope this helps you

Apparently the hue/saturation is in millions of colors using all CMY, but I can only have K and M.

Image, Adjustments -> Channel Mixer

Reduce Cyan and Yellow levels to 0

Still save as .tif

Ah, I misunderstood you mate. Didn't realise you were having it commercially printed (should've!)

You got there anyway!