I've redone the last 3 steps of processing, no Dark Structure Enhance or SCNR (green removal). I also reduced the saturation to a more 'natural' level (at least for me). The dust element is now more prominent.
(http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/normal_SH2-155__E_240_00s_FILTER_LEnh_ABE_EZdcn_dnse_sftstr_strred_DSE_HT_CT_GIMP.jpg) (http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/SH2-155__E_240_00s_FILTER_LEnh_ABE_EZdcn_dnse_sftstr_strred_DSE_HT_CT_GIMP.jpg)
Might have overdone the Dark Structure Enhance script in Pixinsight, but it adds drama :)
107x240s, Gain 120, Offset 4, Temp -5C
Image date, time and location: 2021-09-01+05, Manche France
Telescope aperture and focal ratio: TS1506 f4 Newtonian with TS-Optics GPU superflat 2" Coma Correktor
Camera and filters used: ZWO ASI294MC Pro, Optolong lEnhance tri-band filter
Processing applied: Pixinsight, Gimp (for those who like puzzles, details ABE_EZdcn_dnse_sftstr_strred_DSE_HT_SCNR50_GIMP)
(http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/normal_SH2-155__E_240_00s_FILTER_LEnh_ABE_EZdcn_dnse_sftstr_strred_DSE_HT_SCNR50_GIMP.jpg) (http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/SH2-155__E_240_00s_FILTER_LEnh_ABE_EZdcn_dnse_sftstr_strred_DSE_HT_SCNR50_GIMP.jpg)
"Might have overdone the Dark Structure Enhance script" :o It needs to be used with subtlety 8)
If the dark areas go too black then it's probably overdone.
Robert