I am a relatively new owner of the HP z3100 and I notice that there is very little or no usage of the light cyan cartridege. The other cartridges do show use at various levels. The prints come out fine so I am wondering if this is normal. Please help, if you know.

Alan

If there were a problem with that head or cartridge, the printer would have let you know (in the software.) Maybe now that spring is here you'll do more prints with sky, and the light cyan will be used faster.

I feel you're lucky, as I seem to have the opposite "problem": The GE and Light Gray inks disappear as if somebody drinks them, and the yellow is not far behind!

Yes if you print images with little cyan, aqua, azure etc it won't be used. For more purple blue the new primary colour is used. The Z always use a lot of lGray, and GE if on full page. I didn't notice a lot of yellow though even with skin tones.

I had to replace 6 other colors before I printed enough to replace light cyan.

Here's where I'm at after 1 year and 70 or so foot of 24 inch paper.
Z3100ps GP running MOSTLY in bootcamp on Mac Pro.