[Avodah] Tefillin retzuos black on both sides?

[Rich, Joel]

I once asked my sofer about this (actually, I asked whether to make both
sides black would be mutar, because I thought to make both sides black
was so obvious, I couldn't figure out why no one does it): he said that
the chiyuv is only one side, because you need only one side to face
outwards with black; the other side means nothing. But if you color both
sides black, then you don't have to worry about your retzuot flipping
around and having the raw leather side facing outwards.

I can't say anything about a new minhag. But to have both sides be black
certainly sounds convenient.

Mikha'el Makovi
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In addition IIRC there is a hakpada not to have the reverse side
showing. If I am correct, does anyone recall where this is stated since
the nafka mina would be , is it the hakpada on the reverse side or is it
on the non-black.  It would seem to me the formet or else why didn't
earlier generations color both sides?

KT
Joel Rich
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