Digital BW, The Print

I do have another question today, after all.

In an attempt to see how well my particular setup manages B&W printing, 
I've downloaded Normal Koren's test images. Now I have a minor confusion. 
Of the two test images, one is a B&W JPEG and the other is a "color JPEG" 
which appears as a B&W image. The BW test strips look essentially 
identical, but the two images of Dead Horse Point above the B&W test strips 
look quite different. Which is the most appropriate for comparison, in my 
case? - Calibrated monitor, Epson R1800 printer with custom profile, using 
the color inks to approximate B&W printing.

Bill