The 10c in offset-litho mostly have a vertical direction of paper; relatively few stamps have the horizontal direction of paper accompanied by a rather vague orthogonal watermark that is probably described by others as '"mate nacional".
The paper grid is most likely symmetrical at least there are no clear horizontal "lines" to be seen as is typical for the asymmetrical grid. The surface at the back is rather smooth, no signs of a paper wire imprint whereas at the front the paper fibres are cleary present.
Thus, we are dealing with a so-called transposed watermark Multiple Sun+AЯ (NOT Sun+RA!!!) paper that has the wire side printed. D.A. Bardi mentions the year 1957 when a transition to transposed watermarks occurred. The idea of a transposed watermark is OK as the wire side has been printed on, but this happened to a lot of definitives mainly of the PyR II group in photogravure without coating/varnish. I have to study this further....
What is called "mate nacional" is problaby in fact a mixture of 4:
- parallel watermark + asymmetrical grid
- parallel watermark + symmetrical grid
- orthogonal watermark + asymmetrical grid
- orthogonal watermark + symmetrical grid
The last one occurs most!
The parallel watermark + asymmetrical grid that is just "jumping out" of the back of your stamp [Evita 1952 lower values, except the 45c] is supposed to be imported.
Back to the 10c and type A:
Two distinguished groups of shades are to be seen:
Although you can tell from the picture that the watermark is orthogonal - the line of AЯ is perpendicular to the direction of paper [which is vertical in this picture but horizontal in reality!], the fact that he paper grid is symmetrical can better be seen from the enlarged details...
![Imagen](http://www.galeoptix.nl/fila/argentina/thumbs/arg_1935_10c_offset_m_ortho_07.jpg)