“re-emittance of light with a higher wavelength” I would say that the re-emitted light has a “longer” wavelength. Fluorescence always produces a longer wavelen

“re-emittance of light with a higher wavelength” I would say that the re-emitted light has a “longer” wavelength. Fluorescence always produces a longer wavelength. UVC becomes UVB, UVB becomes UVA, UVA becomes blue, etc. Though different materials increase the wavelengths to different degrees. That is why “black lights” can produce different fluorescent colors.