Chosen Solution
I just replaced my screen assembly (full digitizer, Speaker, camera, etc.) and battery on my iPhone 5s. I followed the instructions on the iFixit website. Got the phone back together again and everything functionally works fine. My screen has much higher contrast than when I took the phone apart. Dark colors seem to blend together making it hard to read some dark text on dark background, even with the brightness turned all the way up. Any idea what might cause this? Could it be a bad LCD connection in the phone or could this be a defective screen? Thank you, Patrick
Most likely a defective screen (you could attach a picture to your question so we can see it to be certain). Contact your supplier about replacing or refunding the screen.