I'm starting to look into putting eyes into a face, and have played around with marbles and ball bearings, so far. I've read that eyes are measured from corner to corner, like this:
So far, the best information about placing eyes in a DIY BJD is from the Yoshida Style Ball Jointed Doll Making Guide, pages 62, 63, 64, and 65:
The size of the foreign-made eyes depends on the individual maker, but the diameter of the eye, including the whites, generally goes from 6mm to 32mm in 2mm increments. In my experience, the size of the pupil in most eyes is around half the width of the eye plus 1mm.
The pupil size I want for the doll I am making here is 9mm, so I take off 1mm to get 8mm, then double it to get an eye size of 16mm. If I wanted to make a cuter, larger pupil, it would probably be good to go one size up. This time, I am going to prepare 16mm gray ones and 18mm green ones.
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