NOVELTY - The method comprises: selecting a hydrogen sensitive pigment from oxides, hydroxides, hydrated oxides, acids, oxysalts and polymetalates of tungsten, molybdenum, vanadium and/or chromium; selecting noble metal nanoparticles from one of platinum, palladium, rhodium and iridium; selecting a nonlayered substrate from one of a fibrous and woven structure; combining the hydrogen sensitive pigment and the nanoparticles to the substrate; and forming a variable or tunable visual detector by penetrating the substrate with the hydrogen sensitive pigment and the nanoparticles using an ultrasonic signal.    USE - The method is useful for forming a variable or tunable visual detector for hydrogen (claimed) detection in aerospace applications, transportation applications, hydrogen plants, oil refineries, ammonia plants, hydrogen reformers, fuel cell plants, and chemical and analytical laboratories.    ADVANTAGE - The method is capable of easily forming the user-friendly detector in an economic manner with high detection specificity, sensitivity, variable reversibility and inherently. The detector is resistance to chemical degradation, operable in a wide range of -100 degrees C to 500 degrees C, durable, stable and reproducible, safe to operate in any environment, and capable of effectively detecting the hydrogen leakage.    DETAILED DESCRIPTION - The method comprises: selecting a hydrogen sensitive pigment from oxides, hydroxides, hydrated oxides, acids, oxysalts and polymetalates of tungsten, molybdenum, vanadium and/or chromium; selecting noble metal nanoparticles from one of platinum, palladium, rhodium and iridium; selecting a nonlayered substrate from one of a fibrous and woven structure; combining the hydrogen sensitive pigment and the nanoparticles to the substrate; and forming a variable or tunable visual detector by penetrating the substrate with the hydrogen sensitive pigment and the nanoparticles using an ultrasonic signal to penetrate the substrate with the hydrogen sensitive pigment and the nanoparticles. The method further comprises: adding platinum metal activator nanoparticles to a hydrogen detector at a level of 0.0001-5 wt.% of the hydrogen sensitive pigment, where the hydrogen sensitive pigment and the metal activator nanoparticles penetrate the substrate material; forming a durable and highly-sensitive, hydrogen-specific visual hydrogen detector with variable reversibility, that detects the presence of hydrogen in a confined environment in a wide range of hydrogen concentrations of 0.1-100 vol.% and in a temperature of -100 degrees C to 500 degrees C, where the tungsten based hydrogen sensitive pigment has a coloration-bleaching cycle, coloration in the presence of hydrogen occurs in 2-3 minutes and the bleaching cycle in the absence of hydrogen occurs in 50 minutes; selecting a hetero-atom from one of vanadium and cobalt; and changing the rate of bleaching in the absence of hydrogen with the hetero-atom. The molybdenum based hydrogen sensitive pigment has a coloration-bleaching cycle, where coloration in the presence of hydrogen occurs in 2-3 seconds and the bleaching cycle in the absence of hydrogen occurs in 2 days. The hydrogen sensitive pigment is tungstic acid particles doped with platinum nanoparticles on a paper filter substrate, where a coloration-bleaching cycle occurs within 50 minutes.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a sketch of a fibrous material.    Fibrous substrate (1)    Micron-sized hydrogen-sensitive pigment particles (2)    Nano-sized metal activator particles (3)    Stream of hydrogen gas. (4)