In QGIS raster calculator I do:
And I get:
The red circle in the middle is like cut in the result, QGIS it's not adding every pixel on each raster, it makes a kind of intersecction...
If i select in the QGIS layer selector the two layers to be added (using blending effects = multiply) i get visually pretty much what I spected to see when making the raster calculation adding:
How could I make a real adding calculation between two rasters?