A device (10) for applying fluid (e.g., etchant) to a substrate (19) (e.g., thin metallic tape) wherein the device (19) includes a head member (11) having means (13) therein for directing a first fluid (15) (e.g, etchant) at an established first pressure against the substrate (19) and means (23) for directing a second fluid (25) (e.g., air) at an established second pressure equal to or greater than the first pressure (at the location of fluid intersection) and against the substrate (19) in the area proximate the first fluid so as to substantially contain and limit the first fluid (15) to impingement substantially only at the location against which the first fluid (15) is designed to strike. Preferably, two opposing head members (11, 11') are utilized, and these may serve to maintain the substrate (19) therebetween in a suspended state. Both head members (11, 11') are movable relative to each other during fluid application. As stated, the device is particularly suited to function as an etcher, but may also serve other purposes (e.g., coating, cleaning, rinsing, etc.).