talked this issue with Nishikawa san and Arthit san.
As Kitti san mentioned, we try to increase PH.
We cannot evaluate printability by ourselves but we must confirm the water rub resistance and cleaning of drying ink film in our lab.
By the way, did you receive the competitor ink sample from Yoshimoto?
If so, please forward to technical side.
If not, please confirm the purchasing, guard house and so on because Iwase san said they already sent it to you 2 weeks ago.