Well, what cahracter? A comic? A photo? An abstract graphic? You need to be more specific. The reason you found no tutorial is that your info is too vague and it seems you are assuming there would be a "one fits all solution" when there are probably 500 different ones...
We are busy with a project that uses live footage of pewter cast characters. I have been able to get them to blink quite believable by using the following method -
1) Take a still photo of the character (in your case - your cartoon character)
2) In Photoshop, create three or so seperate images - each one with a bit of eyelid drawn in (using the same texture ((clone stamp tool helps)) as the rest of the character)
2.1) Third blink
2.2) half blink
2.3) Three quarter blink
3) Save these images as pdf or something and import into your AE project
4) Using the masking tool on two copies of each PDF, name one "right eye" and the other "left eye" and mask out the lid
5) Scale and rotate these layers to cover the original character in a believable way
6) Repeat the above step for each type of eyelid
7) layer the eyelid layers and make them each one frame long - place them in order, and remember to add a reversed sequence for the eye to open again.
in other words open eye, one third blink, half blink, full blink, half blink, one third blink, open.
I hope this makes sense?
It kind of makes sense but not sure about the masking bit. Im not new to after effects so I understand how to mask etc but just not sure how you mean exactly?
admittedly, it is a longer way around, but I cannot visualize eyelids without them being on the character. So I take the full PDF, add it as two layers (same picture) and mask out the eyelid with a bit of a feather. i then use that as the eyelid. The easier way, would be to cut the eyelids out of your PDF files, save them seperately and import those.
either way, showing each eyelid for one frame makes a very smooth and pleasant blink.
No actually I dont need to learn "the basics" Been doing that for over 3 years now including as part of a degree. What I need to learn is something very specific - how to make eyes blink - which is why I am here asking. You see I havent had any experience with character animation. So thanks for your default advise but not neccessary.
Its more about interpreting and putting into practice what people are saying on forums. Its very difficult to understand what people are describing from text.