How to color plastic
I learned about a method to use RIT dye to add color to plastic. Plenty of colors are available and it is fairly easy to do. Why would you do this? One man said he would like bright colored hose because his eyesight was failing.
The dye penetrates all the way through with hard and soft plastic. Sometimes the parts become colored but are still transparent and other times they are solid. For instance, the connector at the end of the hose was transparent with red dye but opaque with black. You just put some dye in water, put the parts in and heat it up a little for a while.
I usually use a disposable aluminum tray (for cooking) and heat it on a barbecue grill or stove. It doesn't need to boil. Put the tubing in there and in about 20 minutes it is done.