Brasil 1954 Bisneta - moiré

[Rein]

In the famous Statesmen series printed in photogravure, the original design has a very subtle set of horizontal and vertical lines, which unfortunately by the usage of a traditional screen instead of a bricklayer screen gets subject to the effect of moiré!

In Brasil this is noticed and interpreted as using 3 diferent types of design which it is NOT!

[Rein]

The division in 3 types - liso, grande and pequeno is a simplification as well!





The 10cr with the large squares has NOT been mentioned before in the discussions I have seen in the Brasil foro http://selosdobrasil.forumeiros.com/t37 ... ia-bisneta



You need to specify the gauge of the screen and also the type of screen!  

Furthermore, the direction of printing is important! The ink flowing downwards [10cr peq] or upwards [10cr gra]...

[Rein]

Moiré patterns obtained by the superimposition of two similar patterns rotated by a slight angle.

[leonardoleidi]

Thank u Rein. Have u made an analysis of serie "Vovó" (1920-1941?). It has a lot of issues, and watermarks and papers, the most difficult in Brazil!!!!

[Rein]

Moiré in a different shape!!  Squares arranged like bands!!

[Rein]

Thank u Rein. Have u made an analysis of serie "Vovó" (1920-1941?). It has a lot of issues, and watermarks and papers, the most difficult in Brazil!!!!

Leonardo,

indeed the Vovó series is quite complicated, but what is more annoying is that - like in Argentina up till some time the Kneitschel - the RHM-Catalogue is omnipotent!

Some aspects are not dealt with!!!

In Argentina the collectors DID realize there was a great difference between Granulado Horizontal, Granulado Vertical, Rayado Horizontal and Rayado Vertical!

In Brasil they do not know that as RHM does not bother about it!

saludos, Rein

[leonardoleidi]

Thank u Rein!

[Rein]

The various types of moiré-effect depend on the type of screen used!

Basically the type of screen used for the Bisneta is the bricklayer-type!  Not just used for this issue but for quite a lot of Brasil stamps up until recently!  






with the base-line for the brick-player in red and the virtual diagonals in yellow!

Schematically:



In contrast with a traditional cross-screen:

[Rein]

The bricklayer screen is responsible for the askew bands, while the traditional cross-screen is to blame for the small boxes [pequeno] and the large boxes [grande] !







the purple lines indicate the angle of 45 degrees that traditional cross-screens make with the horizon!

[Rein]

The traditional method of preparing a photogravure cylinder was to take the original design that was often 4 times as large as the eventual stamp size, and copy it photographically 2, 4 or 5 times and then used that strip of block in a step-and-repeat machine to make up a whole multipositive film of 100 stamps. That film was proceeded and got a  screen projected on it before it was wrapped around the photogravure cylinder; then the chemical  etching could start, etc....

All characteristics of that original 2,4, 5 or 10 stamps would be reproduced 50, 25, 20 or 10 times and were available in a counter sheet.

als these characteristics were already in the multipositve film, a consecutive new cylinder - with a different screen or not - would have the same characteristics!

In the two blocks above several of such characteristics are indicated!  They are NOT plate flaws! They are systematical characteristics  occurring a lot of times per sheet, whereas a plate flaw would occur ONLY ONCE per sheet!

Furthermore it is obvious from this scan that the blocks [xadrez grande] that were caused by moiré are different each time depending on the position in the sheet - theoretically it would be possible to tell the 100 positions apart!  :)

[Rein]

Four of such characteristics!

[Rein]

Another block of 6 with some of the previous characteristics. How big was the base block for the step-and-repeat machine????

[Rein]

Some other blocks of 4 with some systematical characteristics. How big was the base block for the step-and-repeat machine????

[Rein]

Another systematical characteristic!

[Rein]

Passei a véspera de ano novo com a família, mais especificamente com a bisneta. Aproveitei e fiz um artigo explicando a série (pois vi neste forum que alguem perguntou sobre o fundo xadrez - linhado). Pediria a ajuda dos colegas do forum para melhorar , corrigir, propor melhorias neste texto. Como a SPP esta sem atividade nestes dias não tive acesso a literarura nenhuma, apenas aos catálogos que tenho.

Clique no link abaixo:
https://sites.google.com/site/seloshow/ ... ie-bisneta


Tenho interesse em selos da série bisneta - novos - com goma , dos que faltam na minha coleção, que pode ser vista no link abaixo. Se voce tiver alguma coisa por favor me mostre a imagem e que tipo de selo tem interesse para a troca.

https://picasaweb.google.com/1036020192 ... directlink

RHM lists the 0,20 with large squares?!?!?

You don't seem to have it, neither does Guillermo  

Does it exist at all???

It seems to exist at all!

But it has got nothing to do with the colours whether dark or bright!








Both stamps have a traditional cross-screen gauged 60 lines/cm.

The other 4 stamps at the right have a few slightly descending thick bars at the right of the person - Oswaldo Cruz - depicted! This effect is due to moiré




in combination with a bricklayer screen (gauged 80 lines/cm) as it was used from the very beginning of the definitive set - also called here "linhado"....