Between Medium and Bold Extended, I set a Semibold Instance with these setting:
Weight: 487; Width 600
This weight works for the instance but for some reason, if I put a higher value, the Semibold instance looks lighter and if a put a lower value, looks thicker. It works as if it were inverted.
look at the weight values in the next captures. A high value make looks lighter the Semibold instance.
There’s a thing that I did and I don’t know if that could affected the mastering behavior:
The project already had an initial master, with its custom parameter configuration done. I Delete that master because I made new masters (the ones I have mentioned before). I haven’t set the custom parameters for the new masters yet. This could be the reason for this that I identifies as an error?
You do not really have two axis. More one diagonal one. If you do not plan to add more masters, I would remove the width axis. You still can call the instances “Bold Expanded”.
You have two axes, but your designspace doesn’t really use them if all your instances have unique values on both axes.
If you plot your instances on to a chart with width on the X-axis and weight on the Y-axis, they’ll essentially form a single line, since in your instances, width increases alongside weight (why do they do that?). In a symmetrical two-axis designspace, they would instead form a rectangle with four masters:
regular normal (weight 95, width 400)
regular extended (weight 95, width 700)
bold normal (weight 800, width 400)
bold extended (weight 800, width 700)
That is the normal way to set up masters and – assuming your masters are all compatible – instances should work anywhere within that space.