Cardan grille or substitution cipher

[Ruby Novacna]

I have just reread Rene's article about the Cardan grille applied to the manuscript and I have a question: is substitution cipher contrary to the idea of the grille or rather complementary?

Is it necessary to decipher the text first, with good grammar or not, and then apply a grid to discover a particular message?

[davidjackson]

Well, a grille extracts letters from a corpus.
So you could use both in sequence. Get a text out of the page with a grille, then use a substitution cipher.
I don't suppose it makes sense to apply a substitution cipher to all of the text if you're then going to extract only a portion of it.

[Ruby Novacna]

I don't suppose it makes sense to apply a substitution cipher to all of the text

So, in your opinion, the text is not fully coded?

[davidjackson]

That is not what I meant. I was simply thinking about how it would work. 
With a cardian grille you have a lot of nulls (the text that is not selected by the grid).
Why apply a substitution cipher to the null text? You encode your text, and then surround it by nulls.

[Ruby Novacna]

You encode your text, and then surround it by nulls.

The glyphs you call null are still quite elaborate and form "words" similar to the real ones?*
Why should these "words" not be real?

[davidjackson]

Do you know what a Cardian grille is?

[Ruby Novacna]

Do you know what a Cardian grille is?

I know what is written in Wiki, a kind of steganography.

[davidjackson]

It's a method to select certain letters from a block of text. Although there are many forms, it's basically a cut out template you put over the page, and so select certain letters.
The rest of the letters are just nulls and can be ignored.
If you wanted to increase security, you could apply some sort of cipher (ie substitution) to the text before you surround your letters with the nulls. But there is no point in putting the nulls through the cipher.
I'm not saying this is how the Voynich works, just commenting on your original question.

[ReneZ]

The paper is meant to show (among others) that Gordong Rugg's alternative use of a Cardan grill is a special case of, or equivalent with, the use of cipher wheels.
This has the purpose of creating something like a word structure as we see in the Voynich MS.

[Ruby Novacna]

Thank you, Rene and David, for the explanations.