That is a very fine picture!
And congratulations to Raul Villaverde Fraile, who is an excellent astrophotographer!
The colors of this image are subtle and many-hued. Over much of the image there is a "background" of red Ha emission, caused both by all the ultraviolet photons pumped out by the bright stars in the region and, I think, by the general "stormy condition" in the area. But the Ha emission is very red and bright only in the Orion Nebula itself. Not in the Trapezium though, which is bright with all kinds of emission, including OIII.
The dust is pervasive. It is interesting to see how a thick cocoon of dust appears to keep the red nebulosity of the Orion Nebula enclosed. But some of the blue starlight from the hot stars in the Trapezium escapes the enclosure and colors parts of the tattered and broken dust barrier bluish. The bluest reflection nebulosity dust is found in the (much "calmer" and less tattered) Running Man Nebula, where there is an underlying background of deep magenta, a mixture of emission and reflection nebulosity. But with no dust, there is no reflection nebulosity, so wherever you see patches of blue that are not simply "photographic halos", there is dust. Of course all the huge swaths of brown are made of dust, too.
We expect a site of star formation to be dusty. In our nearby, evolved universe, star formation is almost always (and perhaps absolutely always) associated with dust. Clouds of gas contract under their own gravity, and the dust they contain helps them contract and cool, which is necessary for star formation. But star formation in itself produces more dust, and high-mass stars like the brilliant stars in Orion produce a lot of dust (sometimes copious amounts of it) both at the beginning and at the end of their lives.