Dot gain?

I'm working in a project to show some images in lightjet printed black and white paper. Recently I discover that the "suggested" color profile for grayscale in Photoshop is dot gain 20%, I understand what it means in terms of offset printing but not if it is related with another forms of printing, say inkjet, lightjet, lamda, etc. I never bother about a color profile in grayscale mode in Photoshop, and always thought that the best way to work in Mac is using gray gamma 1.8. The question is: does anybody can tell me if this dot gain profile is the one to work in the case of lightjet or lamda?