The colour coding in the QTR ink separation page indicates which ink position will be used to print each row in calibration mode. Each column has a difference combination of Red and Blue at 100%, and then gradually Green is introduced to reduce density down from 100%. On the R1900, shade 1 is in the PK channel, and the colour code for 100% is (253,0,255) (R,G,B).
If you want to put a second shade 1 into another slot and just print the two shade 1's to compare and measure, then you just need to print the two rows from the ink separation page that correspond to the two slots where the inks are.
If this is about the R1900, then the ink separation page has incorrect labels for the cart positions. I posted the mapping between the R1900 and the ink sep page labels in my comments on this post:
http://www.inkjetmall.com/tech/content.php?166-Flush-individual-channel-using-QTR-Calibration-Mode