Hi. I need to use more texture layers for my item, but only 5 layers will load.

    	Minecraft minecraft = Minecraft.getInstance();
    	ItemColors colors = minecraft.getItemColors();
    	colors.register((p_210242_0_, p_210242_1_) -> {
    		if(p_210242_0_.getItem() == ItemInit.LABEL.get()) {
                return ((LabelItem) p_210242_0_.getItem()).getColor(p_210242_0_, p_210242_1_);
    		}
    		return -1;
         }, ItemInit.LABEL.get());

Item json:

{
    "parent": "item/generated",
    "textures": {
        "layer0": "realistic_beer_brewing:items/label/layer0",
        "layer1": "realistic_beer_brewing:items/label/layer1",
        "layer2": "realistic_beer_brewing:items/label/layer2",
        "layer3": "realistic_beer_brewing:items/label/layer3",
        "layer4": "realistic_beer_brewing:items/label/layer4",
        "layer5": "realistic_beer_brewing:items/label/layer5",
        "layer6": "realistic_beer_brewing:items/label/layer6",
        "layer7": "realistic_beer_brewing:items/label/layer7",
        "layer8": "realistic_beer_brewing:items/label/layer8"
    }
}

Is the number of layers limited or why doesn't it work for me?

// ItemModelGenerator.class, MC version 1.15.2, mappings 20200514-1.15.1
public static final List<String> LAYERS = Lists.newArrayList("layer0", "layer1", "layer2", "layer3", "layer4");

It seems coded for 5 item layers. But, as Lists.newArrayList "creates a mutable ArrayList instance", you might be able to add more layers manually.

Oh, and don't call Minecraft#getItemColors(). Register a listener for ColorHandlerEvent.Item (make sure to register only on the client side).