Correspondence with a well-educated Yemenite Talmid (of the Rambam persuasion):

This is a somewhat confusing issue. I'll start with the fact that the Rambam and Tosafot differ in there definition of what is Qlaf and what is duchsustos. To make matters more complex there are versions (albeit printed) of the Rambam that have the Rambam's order reversed. Luckily, the beit Yosef was aware of this misprint, as well as the Maharitz. 

 

Here is the issue: The Rambam writes that Gewil is the full hair and that we write on the side of the hair. Duchsustos is the upper layer of skin (on the upper side) once it is split and here we also write on the side of the hair. Qlaf, on the other hand, is the lower portion of the split skin and one would write on the side of the meat. 

 

The Tosafot have switched the positions of the duchsustos and Qlaf and I suspect certain versions of the Yad still have things reversed as well.

 

The Rambam is very clear regarding what may be written on what. A Sefer Torah may be written on Gevil (first choice) or on Qlaf (second best). It may be written on nothing else. It also requires I'ibud Lishmo (working of the leather for the sake of a sefer torah).

 

tefillin may only be written on Qlaf, which is according to the Rambam on the side of the meat. Once again the working of the Qlaf needs to be for the sake of teffilin.

 

Mezuzot are to be written on duchsustos or Qlaf (second best). Since duchsustos is not really available today and hasn't been since the time of the Talmud (the technology is somewhat lost).
 

### What do you mean by this? If the technology is (indeed) lost (as you say), I assume you are referring to the method of splitting the hide to make the two different pieces. So if it is lost, than our Qlaf is may also be problematic...no? I was under the impression that there are a handful of parchment makers that know how to accomplish this split, so that we DO have Qlaf and Duchsustos today. 

 

  > Fraid Not, just Qlaf and Gewil. In order to produce duchsustos today, one must painstakingly carve away all of the Qlaf (ultimately destroying the Qlaf portion).

*** This doesn't make sense to me. If we are writing on the top part of the top layer in the place of the hair (what we old time Rambamists call duchsustos), what difference does it make if there is a remnant of the split on the bottom side of our Duksustos writing material where the split occurred. We are writing on the top side of the top layer anyway.  

 

 You have a point and that is why not having duchsustos is not that big an issue. Writing on duchsustos that has a remnant left on its back is not duchsustos, it is Gevil. Gewil which is the full un-separated skin is simply thicker and for a Mezuzah one wants thin. Therefore remnants of other layers below, aside from being unattractive and not befitting the mitzvah, are unwanted. The difference in the level of Kedushah is also represented by these different materials. The sugya in the Talmud discusses why one can not take the Shema from a sefer torah or teffilin and use it as a mezuza and the answer was we don't lower the kedushah of the sefer torah or teffilin. In other words nothing, it has nothing to do with the materials themselves. Rather, it has everything to do with the objects. The Talmud then proceeds to outline the materials used for each element and clearly states that these are the optimal materials. From this the Rambam surmises that one may actually use Gevil for a mezuzah (Lechatehila). 

 

If the split we have today (is good enough in the eyes of the Rambam) to accomplish Qlaf making, it must be good enough today to accomplish duchsustos? 
 

The split is now lost. They way in which parchment/Qlaf is made today is by hacking away at any other layers that there might be. Nothing is kept and nothing split. Not only is this wastefull, it means double the work if you want two separate parts. But with the lack of our original splitting process (which was partially a chemical process), we are left with no choice.

 
So here is a diagram:

According to the Rambam in Authoritative Yemenite Manuscripts:

 
Dusksustos  is the top layer  (writing is done on top side) 
_____________________________
SPLIT is HERE
_____________________________
Qlaf is  the  bottom layer  (writing is done on bottom side of this layer) 
 

The misprint in certain versions of the Yad MAY have come about because the Rambam went back and forth on the issue. But this is highly speculative. All Yemenite manuscripts have their text as stated in the diagram above. The other versions seem to have the Rambam agreeing with the Tosafot. Although the Rambam in those texts doesn't seem to describe which side is written on, simply that the D is the lower layer and the K is the upper layer.

***********************
According to Tosafot:
 

Qlaf  is the top layer  (writing is done on bottom side) 
_____________________________
SPLIT is HERE 

 
Dusksustos  is the bottom layer  (I am unclear as to what side they would write on if they had it)

 _____________________________

Tosafot holds according to both inner sides for its terms of Qlaf and duchsustos.
 
We hold to the outer sides - away from  the point of the split.
 

*** Well in terms of dusustos, what difference does it make if there is a bit of Qlaf on the bottom? I don't see how this nullifies duchsustos if we are writing on the TOP part (where the skin was) anyway.  

 

??? Therefore what need is there for this anyway is what you're asking. Precisely. The function of duchsustos is that it is tissue paper thin. It is the lowest grade of writing material and not. Yet the halachah offers this as what may seem to be the optimal custom for a mezuzah. 

 

There is a professor by the last name of Horen who wrote an article on this or perhaps even a book. Someone (non-Jewish) from the Netherlands had contacted him and claimed that he was able to split them after much experimentation. More than that, I do not know.  
 

*** So than logically, we have ZERO Qlaf today too, OR our Qlaf is too thin as part of it is stuck to the duchsustos. But again, as we are writing on the bottom side of the bottom layer for our Qlaf (which is the other side of the split), it shouldn't matter. 

 

???No, that is not what I said at all. 
 

Mezuzot do not require working of the leather for the sake of Mezuzah. The Rambam surmised that one may use Gewil for a mezuzah as well, based on the logic in the Halachah. It was not common to write mezuzot on Gewil, yet according to the Rambam it was permissible. The Shulhan Arukh accepted the Rambam's logic on this point but only allowed a mezzuza to be written on Gewil BediA'avad (after the fact).

 

The mezuza is really the least (in quality) of all of the items. It requires being checked twice in seven simply due to the wear and tear the elements place on it. I still have yet to speak to people (and I know a Rambamist whose business this was in Yemen) to tell me otherwise.

Regarding the availability of duchsustos which seems to be the question of the fellow quoted below.

### Well. His question is for dushsustos (al pi reversed), which would be nothing according to the oldest texts of the Rambam. As I have learned, we may NOT write on duchsustos (even if it was) for the tefillin. However, from our point of view, this is not even dukhsustos (in proper use), as they are writing on the incorrect side of duchsustos and then calling it Qlaf. It's just nothing but writing on the bottom side of the top layer --which is nothing. Either way, I am not mixing into that because I believe it has no basis with all due respect to our brothers.

  

> Sounds to me that he is actually asking for what is called "Qlaf" in all stores today.

*** This is what they call Qlaf ragil -- I presume. Yes, This is what I think he is asking for. However, as I said before, this is nothing to us and can not be sanctioned in my humble opinion. If someone wants this, they can always find it somewhere else.

 

They call Qlaf the underside of the top piece, where the split took place. IE: The top piece --but not written on the side of the hair. This is what the Tosafot people refer to as Qlaf. To us, it is NOT duchsustos or Qlaf. It is nothing. 

 

You are talking about sides of the layers and I was simply talking about the layers themselves in my previous emails. You are correct, there is discrepancy in the sides as well. We hold that they are writing on the wrong side. 
 

then their Qlaf would have to be thinner to constitute (our) duchsustos. There is another issue and that is, which side does one write on.
 

*** Take a folded napkin. It's the best way. Then open it at the crease. The (top side of the TOP layer at the hair) is what we old time Rambamim call duchsustos while the bottom side of the bottom layer (near the flesh) is Qlaf.  

 

sounds accurate

 

 

 To the tosafot folks... it is simple. Both sides are where the split is made. The bottom side of the top layer (at the point of the split) is what THEY CALL Qlaf while the top side of the bottom layer is what they call duchsustos. So either way, what they call Qlaf is nothing to us. This is my understanding after reviewing and confirming with The Moreh yesterday. 
 

I have not seen which side they consider the "writing side" of duchsustos. If it is indeed the upper side of the lower portion, then basically it is the same thing as their Qlaf only perhaps a bit thinner?

 

The reason behind their understanding of all of this is quite simple. Gewil for them was impossible to write on since the area where the hairs were on the cow was too dark to write on. Cows in Europe had more black to them. The hairs were also very thik and left large pores open. Since they did not do I'ibud with Afatzim they were not able to solve these writing obstacles. They simply used the back of the skin which was naturally white and bleached it in sid (pronounced seed) (lime). This goes along with the pergament made at the time by the gentiles. Ashkenazic authorities were more lenient with Qlaf and more stringent with ink. Non-ashkenazic authorities were stricter with the Qlaf (which didn't need to make adaptations to a new setting) and far more lenient regarding the ink.