In this study we present an UV single-photon imaging detector based on a thin-gap Resistive Plate Chamber, featuring a very good position resolution of 30 μ m in a digital readout mode and a reasonable quantum efficiency of 0.3–8% in the spectral interval 200–140 nm. These detectors are inherently spark-protected and can operate without feedback problems at gas gains up to 10 5 . Attempting to extend the sensitivity of gaseous detectors to longer wavelengths, we successfully tested the first sealed parallel-plate gaseous detectors with CsTe photocathodes, reaching a gas gain of 10 3 .