Haddock's stylized pupil-less eyes certainly seem unusual compared to how most cartoon characters' eyes are drawn these days, but it's interesting that they don't jump out at you as being odd, even after you notice that they're empty circles. I wonder if this way of drawing eyes was a more common stylistic device of cartoonists when Hergé was starting out, or if he devised it for himself.
Whatever the case, it seems to suit Haddock. I'd always assumed that Hergé drew Haddock's eyes that way to give him the slightly pop-eyed or bleary-eyed look of a drunkard. But, as you point out, Müller shares the same eye style, and you'd imagine his eyes to be pretty sharp and focussed. Skut's good eye is also drawn this way, and there are no doubt other examples. So maybe it's just a device that Hergé found happened to work for certain characters' faces, regardless of the characters' personalities or habits.
Hergé was very good at eyes. Many cartoonists feel the need to draw eyes as black eyeballs within a white circle, which can help to show which way a character is looking and add to the range of cartoon expressions. Hergé, though, hardly ever draws dot-in-a-white-circle eyes (apart from characters wearing glasses), yet such is his skill in placing his minimalist dot eyes in relation to a characters' eyebrows, you can always tell exactly where a character is looking.
Of course different ways of doing eyes suit different styles of drawing and I'm not saying there's anything wrong with dot-in-a-white-circle eyes; many great cartoonists, such as Ronald Searle, draw eyes like that. But I think Hergé's way of doing eyes as minimalist dots (or minimalist discs in the case of Haddock, Müller etc) adds to the non-cartoony, realistic, deadpan feel of the Tintin books that many of us find so appealing. |