Illustration of the correction. Top: Planck τ353 GHz dust optical thickness in the direction of photometric targets in a region of the sky in the low Galactic latitude part of the Taurus-Perseus area. The image is used to show weak filamentary structures. Middle: corrected extinction for the same targets. Bottom: initial extinction for the same targets. The colour scale is identical to the one used in the middle image. The subtle variations in the pattern in the middle image agree better with Planck structures. Stars from the reference catalogue are not displayed in the images.