ConeColor Photo Black Dmax

I have been replacing the original cartridges in my Epson 3880, as they are used up, with refillable Cone color ones, but when a new photo black cartridge was installed and a gray scale test run, I found that the Dmax was much lower than what the Epson cartridge gave:

Epson photo black: Dmax 2.3 (L4.5)
Cone photo black: Dmax1.8 (L
12.5)

Is this normal? The difference is quite noticeable.
I’m using QUAD tone instead of ABW. All colors except yellow are now Cone inks. The new cartridge installation has been faultless.
Paper is Epson Premium Luster.

Hi Henry~

I checked my measurements for different black inks I’ve tested on different papers.
On JonCone Studio Type 5 paper (baryta surface), I got the following:

Epson PK= 1.849 dMax (12.06L)
ConeColor PK= 2.107 dMax (7.02L)

After reviewing your order history, I see you bought the PK ink and cart in August of this year, so the ink is very new.
Did you shake the ink bottle before filling the cartridge?
Are all nozzles fully printing on your nozzle check?
Do you now have the full set of ConeColor inks installed, or do you still have some Epson carts installed?
Did you get these measurements by printing the Ink Separation image thru QTR’s Calibration Mode (measuring pure ink from each channel)?

Please let me know, thanks~ Dana