I think the most commonly used and easiest technique for eyelids is the replacement method, where you make a bunch of lids at different points of open-ness and swap in each one when necessary. You could sculpt them out of polymer clay or similar. I have experimented in the past with trying to use wire and thin sheets of stretchy stuff to have the eyelid built into the puppet, but it seems to always end up too bulky, and it stretches weirdly when closed and/or bunches up and wrinkles when open. I'm not the most experienced animator though, so maybe someone else will have ideas for you. Good luck!
I've animated on someone else's film (Butterflies by Isabel Peppard) where she made replacement eyelids in silicone, complete with eyelashes. A dab of petroleum jelly is used to stick the eyelid onto the eyeball. There were very slightly closed upper lids, half closed lids, maybe 3/4 closed lids, and fully closed lids.
This shot has the girl with the slightly-closed lids on:
On my puppets I mostly use a bit of flesh coloured clay to make the replacement lids, or else do the eye blinks in post production. The silicone lids are better, but its really easy to lose one if they are for smaller eyes.
Another method I've used for foam latex, but not so far with silicone, is to have thin shells that fit between the rubber eye socket and the eyeball. They normally slide up so they are mostly inside, but can slide down to close the eye. Cosgrove Hall used metal shells for Mr Toad in their Wind In The Willows series in the 80s, that's where I got the idea, but mine were vac formed styrene sheet. Some weren't done with an actual vac former, I had a sphere the same size as the eyeball glued to a block of wood, without 1/4 of it sunk into a hole in the wood. I heated the styrene sheet over a bar heater then pushed it over the sphere with a piece of tube that was a little bigger than the sphere. It stretched over the sphere and cooled. I trimmed off the excess, built up the edge of the eyelid with a bit of epoxy glue, then painted it. There was an upper and a lower lid. This hatchling has the styrene shell lids in the almost-closed position:
Thank you both for taking time to respond.
I am happy to hear I was not missing something obvious - it is clearly some additional work to do the eyelids - it is stop motion after all.
Thanks for the ideas - I now have a path forward and will get to work.
And don't forget the option of doing them in post. A lot less fiddly!
Simon, and others
Do you know of any videos you can point me to that had the blinks added in post?
I would like to see what this looks like.
This video that I did before Christmas had blinks done in post:
I mostly only did the one eye as the other was in deep shadow. It was done in Photoshop.
Thank you for pointing me to your video. I enjoyed watching it and seeing the "post-blinks" was very helpful