Ipe supports a simple model of transparency. You can set the opacity of path objects and text objects: an opacity of 1.0 means a fully opaque object, while 0.5 would mean that the object is half-transparent. All opacity values you wish to use in a document must be defined in its stylesheet.
Adds transparency values 75, 50, 25, 10, 20, 30, 40, 60, 70, 80, 90 in percent. Check transparency.isy