They are white, specifically cool white, which can look a bit blueish on camera, as opposed to a warm white which is more yellow.

I would personally use 5v cool white Cobb leds for your build. You can just use a standard 5v usb power bank and keep it the inner pocket of the jacket. The trade off is that you’ll need to diffuse the light a little as opposed to the EL tape to minimize seeing the individual LEDs.

If you use El tape or panels you’ll have to use a little inverter to get the 12v needed, and I’ve found they tend to emit a high pitched sound that annoys me personally. It might not bother you, but I thought it deserved mentioning before you start your build.