Sosha,
The portraits are punchy and have a good impact factor. If I'd been asked to comment on them more generally (without your specific question regarding Ilfosol), my thoughts would have been a) you have a bit of a problem with dust particles, b) watch out for what's behind the subject (verticle posts in two cases) and c) to my eye, shots 3, 4 and 5 have too much headroom, though of course that's subjective and perhaps a case of convention vs. personal style. Please take my comments as they are meant - in a constructive way. My favourite is no.2, which doesn't invite any of my comments above!
Best wishes,
Steve