QTR 8RC Sensor can't properly Detect

I am using a QTR-8RC sensor and I am testing it using the example sketches from the library. I noticed that the sensors values are not what i expect it to be. For instance, when I put 1 channel of the sensor to the black line, one of two things happen: either the value will not significantly change or the value will change but it changes along with the other values which I do not expect to change. Although, it seems that the sensor works since when I lift it up, all the values change to 2500 and when i put it down to a certain height, it lowers. But the problem still exists. Basically, I have inconsistent raw data.
I did try to change the sensor height and the platform used. Originally, I printed a black line on a sheet of paper, then I switched to an electrical tape on a sheet of paper, then I printed a black line on a glossy sticker paper. All of the setups showed similar results.
In the test, I used both arduino UNO and pro micro. Both are powered via USB.

Hello.

Can you post some pictures of your board that show all of your connections?

In case you have not already, please try out the QTRRCRawValuesExample.ino example program from our Arduino library for the QTR sensors with minimal modification. To see what is going on, I suggest facing the sensors upwards (indoors, away from any windows) and closely covering the sensors one at a time by hand or with a dark piece of paper in a way that you avoid casting shadows over other sensors. Can you post a sample of your Serial Monitor output that shows what happens during that test?

- Patrick