Prepare some resin glue. Mix up A glue and B glue according to the proportion of 3:1. Usually we will use two different cups to contain A glue and B glue individually according to the proportion. Mix up the two glues completely and stir it evenly.
The made up resin glue needs to be separated into two. One of them will be added in with white pigment and the other one will be added in with black pigment. Stir them evenly for the color to be mixed completely.
On the high side of the models, we will pour in the black resin glue slowly. Then we will put all the models on a same level. Now we see there are two kinds of resin glues of different colors inside the models.