Brush Tool is Acting Odd - Probably an Easy Fix!

Hey everyone, I’ve got a question about the brush tool. It’s probably something really simple, but I’m really new to Toon Boom Studio, so bear with me. I’ll pick a colour to draw with the brush and as I draw a line it’ll look like that colour, but as soon as I take my stylus off my tablet the lines look faded and weird. I’ve screencapped an example:

http://imgur.com/3M2IUM3,iCMVjWz#0

http://imgur.com/3M2IUM3,iCMVjWz#1

Any explanations/fixes are greatly appreciated!

Hi, There,
What’s the graphic card you have in your computer ?
Which tablet you are using ?
Wei