power supply for a printed resistive flexible heater

Hi I am a newbie I would like to get an advice for a printed resistive heater I am working on . The heater is a heat resistant thin film on which I printed patterns made out of resistive ink carbon/ graphite/ ferrous material each connected to the power supply via a more conductive ink (silver ink).
My goal is to do some kind of multiplexing to turn on and off certain areas my patterned circuit .Here is my questions is there an idiot proof way to calculate the power needed to turn my half millimeter resistors red hot ?

I Have Seen people turning graphite leads into incandescent light with 24volt 2 amp
How can one build a simple power supply to produce the Power Required will A joule thief do The Job ? If yes how ?Because I have tried I don't know what I am doing wrong I am getting 5 volt from a 9 volt battery the only think getting hot seem to be my transistor . My ideal solution would be to pulse high current to the resistors from capacitors connected to a usb power supply but I don't know if that's possible and I surely don't what Kind of capacitors to use


Apologise for my lack of knowledge and I hope to get a feedback soon .

What is this for? Can you post a photo or schematic?

PS 24V @ 2A is 48W, that's a lot of power. Not going to get it from a USB port or a 9V battery.

e.g. 48W / 5V = 9.8A more when you include conversion losses.

Hi thanks for the quick reply posting for my phone don't have an image at the moment . You can view it like some sort of thermal display the heat is supposed to change the color of a thermochromatic material but the smaller I want the resolution to be the more power I need . I figure that the usb wouldn't provide the power that's why I thought of the capacitors since I don't need it to run continuously. But it really doesn't matter where the power comes from i just need a simple schematic for the newbie that I am the more amp the better.

Why not just buy a 24V @ 2A power supply. Some laptop supplies are 18V @ high current.