Examples of the wavelength-dependent IGM processing for a source at z = 6 situated in an ionised bubble with R_ion = 0.5 pMpc and x_H I = 10⁻⁸. Intrinsic Lyα line profiles (dashed coloured lines) are asymmetric Gaussian profiles with varying velocity offsets Δv_Lyα and an intrinsic FWHM of 100 km s⁻¹ (top panel) and 300 km s⁻¹ (bottom panel). Observed line profiles (solid coloured lines) are convolved to a fiducial spectral resolution of R = 1000. Above the peak of each observed profile (indicated by vertical dotted lines), the true transmission fractions (total flux of the observed line profile divided by the total intrinsic flux) are annotated, while those estimated based on the transmission curve at this wavelength are shown below.