Adjust contour fill transparency in Surfer

You can adjust the opacity of the fill colors while leaving the contour lines and labels fully opaque. The color scale, if present, is automatically updated to match the new fill transparency. To make only the color fills transparent (leaving the contour lines and labels solid):

1. Select the Contours layer in the Contents window.
2. In the Properties window, click the Levels tab.
3. Enter the Colormap dialog. How you do this depends on the Level method chosen.
   1. For the Simple level method, click the  button to the right of Fill colors.
   2. For the Logarithmic level method, click the  button to the right of Fill colors.
   3. For the Equal area level method, click the  button to the right of Fill colors.
   4. For the Advanced level method, click the Edit levels button. In the Levels for Map dialog, click on the Fill header button. In the Fill dialog, click on the Foreground Color button.
4. In the Colormap dialog, you can set individual colors to be transparent or you can set all colors at once.
   1. To set all colors at once set the Opacity value to what you want. 100% opacity is completely opaque. 0% opacity is completely transparent.
   2. To set the opacity for individual color nodes, you can select a node in the Opacity Mapping section and type in a new Opacity for the selected node. To add new nodes, simply click on the line to add one. To delete a node, select the node and press DELETE. 
      
5. Keep clicking OK until you're out of all of the dialogs you had opened.

To make the entire contour map layer transparent (including color fills, contour lines and labels):

1. Select the Contours layer in the Contents window.
2. In the Properties window, click the Layer tab.
3. Decrease the Opacity as desired.

The color scale, if present, is not modified when changing the layer opacity. To match the color scale opacity to the contour layer opacity:

1. Select the Color Scale in the Contents window.
2. In the Properties window, click the General tab.
3. In the Color Scale section, set the Opacity to the same value as the opacity for the contour layer.

Surfer contours with a hatch vector pattern fill using a
transparent background.

Updated December 19, 2021