NO NO NO NO!!! No offence mike but DO NOT USE DUCT TAPE ANYWHERE ON THE INSIDE OF THE SNAKES HOUSE. It sticks to their scales and is very difficult to remove. If they struggle it can rip scales off and gives bacteria a good entrance into the snake and that can cause even more problems. Its one of those prevent problems before they start things. You may not have problems, but if you do they can be very bad. Here is a thread for somewhere else to let you know what can happen.
http://www.ssnakess.com/forums/gener...-tank-viv.html
I would strongly advise against it. IMHO
You can do other things to darken hides like spray paint with a clear outer coat, or make some clay ones with that clay that you bake and it gets hard. There is a thread about how to make home made hides.
http://ball-pythons.net/forums/showt...0-Hides-my-way
NO TAPE OF ANY KIND IN SNAKES HOUSE!!!