Example DEEP2 spectrum of source 9550, whose emission lines are not detected in the OTELO pseudo-spectrum. The line (red arrow) is detected in the DEEP2 spectrum with a very low S/N, indicating intrinsically weak nebular emission. At this redshift, Hβ and both [O III] emission lines fall within the OTELO wavelength range (8950–9300 Å), but their expected fluxes remain below the OTELO detection threshold and may lie close to the edges of the wavelength coverage. Therefore, this source is not classified as an emission-line object in the OTELO survey.