Experiment:

To begin, take indigo dye powder or concentrated blue indigo dye. Add a small amount of water and stir it to achieve a consistent solution. Gradually add water to achieve a dark indigo hue similar to lapis color. Dip the paper to allow the dye to penetrate. For a darker hue, let the paper stay in the dye bath longer. For a lighter hue, remove the paper from the dye bath as soon as you achieve the desired shade. Then, let the paper dry in the shade. For a more consistent color shade, dip the paper in the dye bath and let it dry vertically.