Iso surfaces 

General options

Display Style: For iso-surfaces there is also a Display Style option, like for Volumes/Surfaces/Cuts. The available options are: All Lines, Hidden Lines, Body, Body Lines (see View style ).
Transparency: The iso-surfaces can be set to Transparent or Opaque (see View style).
Color Mode: Allows the user to define the colors used to paint the iso surfaces:

Monochrome: All the iso-surfaces are drawn with the same color, which can be adjusted with 'Change color'.
Mono color: Allows to define the color of the monochrome iso-surfaces, including the transparency factor.
Result color: Each iso-surface is drawn with a color indicating its value, the correspondence of which can be seen in the legend.
Contour fill color: The iso-surfaces are drawn with the color scale of the current contour fill, i.e., the current contour fill is also drawn over the isos-urfaces. If no contour fill is displayed, then the monochrome color is used.

Draw always: With this option the iso-surfaces will be drawn although the mesh is switched off.
Show isolines: When the iso-surface result option is selected, the iso-surfaces of volume meshes are created as isolines for surface meshes. With this option "Show isolines" the user can switch these isolines on or off.

These options also are used for isolines.