What I meant by my post was that I have a portfolio filled with insane color pieces big and small, as well as solid black and grey work. I get customers all of the time asking "can you do this?" (shows feather, symbol, lettering on Pinterest on their phone)
Imaging the frustration. Yes, I can do that you are in good hands.
A separate portfolio would be for those asking "what kind of custom, color ect, or what kind of tattoos do you love to do" that's really it.
The separate lettering portfolio I suggested to on of my fellow artists who did INCREDIBLE custom lettering but constantly encountered people wanting a font they found online. I told him to put examples of his custom lettering to show people what other options were out there.