I am watching I'm Alan Partridge and the picture quality is terrible. Have Dave applied a film effect or is this a mistake? I watched another episode on a previous day and that was the same. Mistake or something else?
I've noticed the source quality of some archive programmes can be noticeably poorer in quality than more recent repeats - wondering if that may just be the case here. While the 'HD' (in this case just higher quality) broadcast obviously can't fix things, it does offer a slight improvement and preserves what quality there is.
If colours like bright reds look less rich and smudge or bleed just a bit, or there are 'halos' along outside-edges of objects, I think that would indicate a lower quality source rather than the result of any sort of effect. It would depend on what sort of artifacts are being created - if it's motion-related then it may be something else.