Welcome to TVPaint Community forums !

I'm working on TVPaint from a Wacom Cintiq tablet.

I like to play with the pressure i put on my pen to get my stoke wider or thiner.
What I don't want tough, is the stoke losing opacity when I put less pressure on my pen.

How can I fix that?

Thank you

Not sure I exactly understand the question but I think what you need to do is to connect the size to the pressure and disconnect any thing linked to the opacity.

If you use any basic tool this should already work so you shouldn't have to do anything. Have a look at the manual in chapter 7-31 onward to learn about connections.

hope this helps

keep your pen's size set to P (for Pressure), but its Power set to C (as in None -- go figure ) and Opacity at 100%, Drying checked and AA checked. Adjust your sensitivity to weight applied on pen between Wacom (the Tip feel) and TVP's Profile Editor (the little window + RMB next to "Size" where you see the letter P) When the curve bows up from right to left, the sensitivity of width in your stroke will be greater, feeling like a dippy pen with a sensitive, soft nib, or if you make the curve bow from left to right the sensitivity to pressure will require of you to apply more weight on your pen, thus the pen's "nib" will feel harder.

After playing a bit between Wacom's tip feel and TVP's Profile Editor you'll learn which settings fit your current needs best. Warning: I find myself playing with these two settings quite often, depending on the nature of my current drawing's size and my frame of mood of the day.