water soluable ink similar to sublimation

There are some t-shirts that I really like the look of and was told by the person that makes them that it is a water soluable ink. It is like sublimation since it is in the fabric not like a transfer or screen on top. You do not feel it but it is on Cotton. Can someone tell me what this process would be for cottons? I know you can sublimate but that not generally cotton.
Thank you and have a blessed day.
Sharon