Thank you for your very
Unless I err, there is only one major point
on which we fully disagree: The use of tin (or tin and alum mixes) as
being the «little secret» of the bright Salor red.
Your hypothesis is
that by increasing the madder concentration of the dye-bath from 100% wof
(as in the few examples shown in my essay) to, say, 250% wof, one would
obtain a bright Salor red with alum, without the need of any tin mordant.
Let’s first agree about which kind of Salor red we are
discussing. My essay targeted specifically those reds featuring a much
brighter and saturated red
shade than usual for Turkmen and not the
various saturated but dull ones
which are much more common on Turkmen
rugs of all origin, including Salor.
From previous posts of yours,
I take it that you have knowledge of dyeing, thus you must know by
experience (and from the knowledge of the basics of colorimetry) that
increasing the concentration of a rather dull chromophore (or mix thereof)
in the dye-bath will of course lead to a more saturated shade (under the
same and proper dyeing conditions), [b]but it will also always make the
. The only way to achieve a saturated and
shade is to use a brighter chromophore to start with.
component of madder on alum-mordanted wool leads to various but invariably
relatively dullish shades (from «tomato» to «brick»), and of course, their
mixes make the shade, if anything, even duller.
Every single component
of madder on tin-mordanded
wool are significantly brighter than
(the same) alum-mordanted ones.
Although the usual laws of
colorimetry apply to all dyes, -natural & synthetic- you will perhaps
find solace in the fact that I did not rely only on theory or experience,
but did include various dye concentrations (roughly between 10% wof and
200% wof in my little experimental program and that it confirmed the rule
It is true (as I mentioned earlier in an answer to
Marla) that increasing the dye concentration in the madder dye-bath
changes their relative concentration on the fiber, thus influences a
little the shade, but it does not help much the brightness and IMHO it
cannot be the «little secret» of the Salor. I do of course respect your
opinion, but allow me to argue my point a little more.
changes (as I mentioned in the post to Marla) are due to two main
a) The various red components of madder do compete with
each other for an access to the fiber. Without going into too many boring
details of the mechanism of wool-dyeing, each of these red molecules
feature somewhat different levels of «hydrophoby», «affinity» and even
«molecular size» (dimension), since some are still in glycosidic form
(linked to a sugar to make it simple) while others are already aglycones
(freed from the «sugar»), some contain a carboxylic acid substituent and
some don't. Thus they are not perfectly «compatible» as we say in our
obscure dyer’s jargon.
b) Some dye components (most prominently
pseudo-purpurine ) are not very stable and can incur in reactions of
«decarboxylation», «hydrolysis», etc.. In the case of pseudo-purpurine,
(which, together with alizarine, you suppose to be the key for the making
of a bright Salor red) it tends to transform itself into purpurine, this
chemical change being rather quick in a hot dyeing bath and being
influenced as well by the pH.
Focussing on your hypothesis: : «In
the sense of Occam's razor I would state that this bright Salor red is
nothing, out of this world". It is a very carefully done madder only dye,
executed in such a way that one has only alizarine and pseudopurpurine as
constituents of the final dye lake (and nothing else from madder!) - and
to obtain that I would use 250% of the wool’s weight of the best available
(Anatolian; it is better than Turcomanian) madder.
», I am sorry to say
that I disagree with this statement:
1) A dye-bath with «only
alizarine and pseudo-purpurine» implies, in my modest opinion, a cold
operation (I believe that in any «normal», hot-dyeing with
madder you would inevitably have a large concentration of purpurine and
much less pseudo-purpurine, would you agree?).
2) My own lab trials
(still, about a dozen so far) with high concentrations of madder in the
bath and various cold dyeing
conditions (thus with probably the
closest possible composition to the one you expect to be favorable for a
Salor bright red, yielded significantly more yellow
coral to dullish orange) than the usual turkmen brick to tomato shades
obtained with alum mordants in various hot
(and therefore poor in
pseudo-purpurine) conditions. Thus things aren't quite going the right
direction, are they?
Besides, making a very
saturated shade in a cold dyeing process is not a piece of cake (very long
I happen to have at least one rug in my collection in
which the madder dye was applied in what the dyer describes as a «summer
fermentation» process, meaning a very long process (several weeks) at an
average temperature probably close to 40-50°C. The shade was, I suppose,
likely to have been more influenced by pseudo-purpurine than the average
hot dyeing process, but the shade, while superbly saturated, is not in any
way a bright «Salor red».
Let’s agree to disagree on this will
you?: I do believe that madder mordanted with alum has little or no chance
to achieve the bright Salor red shades discussed in this thread and that
tin is still the more likely «culprit».
Now for a couple of minor
1) I haven’t spoken in my thread of cold mordanting with
tin, did I? It is true that tin chloride (which, as such, is water
soluble, by the way) converts (in a few minutes) in a poorly soluble white
hydrate suspension. But, this suspension lends itself quite well to a
, under any usual hot conditions (Tests run between
60° and 90°C were all OK, please note also the use of the «cream of
tartar» buffer in the mordanting recipe ).
2) Having tested my
tin-mordanted, madder-dyed wool samples with various ISO and AATCC -normed
fastness tests (competently run by my former company’s lab) and having
done a few more tests which were the fruit of my own hardly limited
phantasy (like long exposure outside, including months on the roof,
rubbing fastness, etc..), I feel confident that the wool was not damaged
by the tin mordanting & rinsing treatment. It did not come as a
surprise to me though, since contrary to your informations, tin-mordanting
on wool is not a process recently introduced by hapless hobby dyers, but
was well known and much used by pre-industrial eighteenth century European
dyers, was well documented and was «sanctified» as the only accepted
method to obtain the «grand teint label» for bright reds. There is no
reason to believe that this process could not have been discovered, even
earlier perhaps, in other parts of the world.
Anyway my opinion is
that tin-mordanting might be, potentially, a threat to the stability of
the wool polymer, but avoiding corrosion is not such a « very very tricky
task» after all, if only wasting some good fresh water for a very thorough
rinsing is sufficient (I swear I did nothing more complicated than that,
neither do the eighteenth century recipe books mention any Harry Potter
trick). Then, Michael your flashing bright red socks do not feature any
suspect hole do they? Unless the dyes were synthetic or Einstein’s
cleverer brother was the madder/tin dyer......
3) The fact that tin chloride
(probably because of the imperfect solubility of its hydrate) tends to
distribute itself more unevenly on wool than alum is very easy to verify.
I invite you to try it by yourself. It would never be a problem in any
modern industrial dyeing machine of course, but an abrash is more
difficult to avoid in my old AHIBA lab dyeing machine. It would be even
worse in any pre-industrial or tribal «equipment». But then Salor Turkmen
never had the reputation of being incompetent dyers, did they?
As you have surely understood while reading my paper, my point was that
madder & tin is sufficient
to obtain brighter reds, of the
Salor type, but would these guys also have mastered the use of cochineal
(thus understood the necessity of using soft water for it), they could
have done even better (a brighter red still). As I wrote earlier, there is
no experimental proof yet that they did so, but, to my very limited
knowledge, very few Salor bright reds have been tested sofar. So, IMHO,
«it does not prove that any hypothesis based on insect dyes is wrong
within this context», it rather means that there is no experimental proof
yet to a reasonably credible hypothesis
. Do you agree?
, I am also quite content with leaning back in my rocking chair and wait
for somebody's hard work to bring any evidence, pro or contra.
Thanks for the flowers Michael, but I would never undully claim that I am
the first one who «emphasises the importance of minor mordants like
calcium, magnesium or tin». In fact I know of a handful of good university
papers which explored their influence on cotton- and wool dyeing.
Including one from Marmara University, therefore surely well known to
Prof. Böhmer too. Although these students were usually virgin of any
knowledge of dyeing science (this is no oxymoron!) or of industrial
dyeing, some of these papers are very interesting indeed.
apologize to the other Turkotek readers for being such a monomaniacal