I'm not a video editing type, so go easy on me ... practically don't know anything on the subject

except that for some videos I view, "color modifying" works (buttons n, j, r for reset ...) and for some it doesn't. What influences that and how can I incluence contrast, saturation and so on on every video I play?

(mostly some recordings of experiments in poor light conditions, so those controls really come in handy when viewing some details before taking out snapshots for reports)

Also, KMPlayer has an enormous number of options. Is there one somewhere that can take a snapshot in a predefined directory of the what-I-see-on-screen every xy number of seconds?