Real Deal Spolas

[Feinman]

Well,  As for alum tawing, even if they had it, it is unsuitable for making leather armour; it makes it very soft, hygroscopic, and the alum will wash out given the chance.  As for white leather created as part of the tanning process --well maybe!  But, just the upper is white on that shoe, perhaps it is alum tawed; the tough sole is made of a darker leather / hide.  If there was a layer of white leather over some kind of sealed hide, it would need to be sewn to the lower layers to be integral, and that isn't always apparent in depictions.  If it is possible to bake hide and then oil it that is wonderful, but does it really make it water resistant / proof?  Also, it seems like some of the depictions have white pigment applied to the fresco to emphasize the color.  I suspect that it was some kind of finish applied to the leather (pure supposition).  White pigments remaining on ancient statues exposed to the elements must have had some kind of waterproof binder.. As white lead was a flexible and water resistant pigment when ground in a drying oil, perhaps that was used on the exterior of the armour. It would essentially be oil paint.  Drying oils were applied as varnishes to art to protect it, so it would seem possible that it could have been the paint used on outside statues and other items too.  Just my two cents.

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Ancient white lead and leather:

https://books.google.com/books?id=2i68AA...er&f=false

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More on white lead and it being waterproof, flexible:
https://books.google.com/books?id=Wd41AQ...ek&f=false

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The birth of patent leather


Yet another legal patent was awarded in 1854. This listed the varnish ingredients as including oil, amber, Prussian blue (Fe7(CN)18 and described as the first modern synthetic pigment), litharge (a natural mineral form of lead (II) oxide), white lead, ochre, whiting (powdered and washed white chalk), asphalt and copal (resin from the copal tree). During these early days of patent leather production, many tanners kept the finer details of their coatings a closely guarded secret, so even the substances listed in patent applications may well have been falsified in order to confuse their business competitors. For many decades, linseed oil and Prussian blue dye seem to have been the basis of most patent leather finishes. Using fine, black leather, the tanner applied as many as 15 coats of varnish, allowing the substrate to dry each time in the sun or in gentle heat from an oven. The aim was to achieve a finish that was smooth, hard, and also somewhat elastic, to avoid the leather cracking when in use.

https://www.satra.com/bulletin/article.php?id=1787

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Ah...  Here we are:
https://chestofbooks.com/reference/Henle...ather.html
I'd be using titanium white instead... 

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I've stopped this project, because I now feel that the spolas was likely made from layers of leather, perhaps water-hardened, instead of oiled and waxed hides..  Rawhide is still too susceptible to moisture, even wrinkling with humidity in the air, though it could be used for scale armour if sealed properly.  I am going to suggest something controversial..  I suspect that the white color seen on what could be spolioi in depictions might actually be lead white ground in oil.  Here's why:  The other white pigments available at the time are too powdery --they would crumble right off the leather, and they don't have the covering power of white lead, as well as being extremely susceptible to moisture.  Painted designs wouldn't adhere properly etc.

Have you thought about baking rawhide to remove excess moisture and then sealing it?

I'm also of the opinion that the pteurges could be made by tablet weave from suitably robust twine and I suspect would hang better...

I think the spolas could be covered with a white leather, tawed and even tanned leather can be naturally white or close to it.

A White Hellenistic shoe from Egypt (allegedly)

https://collections.mfa.org/objects/164463

To me it looks like alum tawing.
http://www.raisedheels.com/images/Amanda/damenschuh.jpg
http://www.raisedheels.com/blog/?p=1339
"The shoes were closed, but considering the weight of the leather, I whipped in a heel stiffener and a toe stiffener, to ensure a greater longevity. The extant pieces were likely made with alum-tawed calf, which was more robust than the leather used here. I was uncertain of the origin of the tanning, but though it seemed to be chrome-tanned, it seemed to have several qualities of alum-tawed leather in that it did not have the typical “white-blue” sheen that most white alum-tawed leathers can take on."

[Dan D'Silva]

I've been messing around with premodern paints on leather. So far it seems to me that oil paint can work on rawhide, but on veg-tan the oil gets sucked up by the leather before it has a chance to cure, leaving the pigment to crumble off the surface. It would require a flexible, non-absorbent primer if the armor is also going to flex.

[Feinman]

I've been messing around with premodern paints on leather. So far it seems to me that oil paint can work on rawhide, but on veg-tan the oil gets sucked up by the leather before it has a chance to cure, leaving the pigment to crumble off the surface. It would require a flexible, non-absorbent primer if the armor is also going to flex.

That makes sense! Thanks, Dan. I'm beginning to think as Crispianus mentioned before, that veg tanned beige leather from natural tanning materials is the way to go. It's out there, on eBay and Etsy..

[Feinman]

Okay, have purchased a piece of 11 oz Europpean veg tanned leather that is a pale color, should be perfect:
https://www.ebay.com/itm/VEG-TANNED-Cowh...0009.m1982

More pics of the same stuff:
https://www.amazon.com/Sepici-Leather-Ve...B07MY92YRN

[Sean Manning]

I've stopped this project, because I now feel that the spolas was likely made from layers of leather, perhaps water-hardened, instead of oiled and waxed hides.. Rawhide is still too susceptible to moisture, even wrinkling with humidity in the air, though it could be used for scale armour if sealed properly. I am going to suggest something controversial.. I suspect that the white color seen on what could be spolioi in depictions might actually be lead white ground in oil. Here's why: The other white pigments available at the time are too powdery --they would crumble right off the leather, and they don't have the covering power of white lead, as well as being extremely susceptible to moisture. Painted designs wouldn't adhere properly etc.

But like Joe says we don't have evidence for tanned leather anywhere near Greece before the 5th/4th century BCE, and those hardened leather flasks (there were two separate technologies) seem to be a high medieval invention. The shoulder-flap cuirass appears in the sixth century. In cultures with a bit of tanned leather like Viking Age Europe, vegetable tanning is often reserved for thin skins.

I would think that fat/oil curing, for which we have a lot of evidence from early Greece (its in the Iliad ...) and Egypt and the Near East, is more promising.

[Dan Howard]

Agreed. If rawhide isn't suitable then the best contenders for this project would be fat-tanned or oil-cured leather.

[Feinman]

Agreed. If rawhide isn't suitable then the best contenders for this project would be fat-tanned or oil-cured leather.

The problem with oil tanning is that it would make the leather soft, and more easily cut. Also, at least with modern tonnage, is that they are all quite dark, soft, and wouldn't take any kind of painted decoration, not even oil paint.  So perhaps an unknown veg.tanning method existed.  dunno.

[Sean Manning]

How do you know? Traditionally many wearers liked linen armour to be soft, and since they don't make these leathers for these purposes any more, there are lots of misconceptions.

Wasn't the buff leather used for protective coats and harness in the 16th-18th century oil or fat cured? And have you looked into Russ Mitchell's Magyar coats or medieval cordowan leather shoes? I would start by seriously researching leather processing techniques and try to find one which fit the evidence.

[Feinman]

Right, "dunno". but, just because Homer and some others might describe a process for making soft leather, it doesn't mean that was the only way. Buff coats: don't seem to match stiffness in vase depictions --do you see wrinkles in those? (we need to make a distinction between those that might depict quilted linen or twining vs. leather), seem to be used in countries where waterproofing was needed. Folks in Africa have apparently known for a long time how to do it:
http://www.gateway-africa.com/howdidthey...-roots.jpg

http://www.gateway-africa.com/howdidthey...skins.html

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"Academicky":
https://www.academia.edu/36710424/_Veget...hers_2018_

[Feinman]

More:
https://books.google.com/books?id=u6Y3AA...nt&f=false

https://books.google.com/books?id=s92KAg...er&f=false

[Dan Howard]

The scale armour in Tut's tomb was most likely oil tanned. The black goo that was found on the armour is what happens when oil-cured hide deteriorates.

Buff coats aren't armour. They are regular clothing meant to be worn under a cuirass. Their earlier coats made from linen, cotton, or hemp were susceptible to powder burns so they replaced them with buff leather and woollen ones.

[Feinman]

The scale armour in Tut's tomb was most likely oil tanned. The black goo that was found on the armour is what happens when oil-cured hide deteriorates.

Hulit said it was translucent, i.e. light could pass through it. Tanning oil or veg creates an interlocking fibrous network that is opaque.  I suspect the goo was just just rawhide scales that had broken down in addition to some protective shiny coating that was probably oil based.  In Homer the oil must be worked into the hide by manually bending the leather until the oil is worked into it, also made it soft.Tut's scales are also painted red on one side;  no period paint would stick to oil tan --I don't even think acrylic would.  the red paint would need to be sealed along with the hide or it would stain things.

[Crispianus]

The scale armour in Tut's tomb was most likely oil tanned. The black goo that was found on the armour is what happens when oil-cured hide deteriorates.

Hulit said it was translucent, i.e. light could pass through it. Tanning oil or veg creates an interlocking fibrous network that is opaque.  I suspect the goo was just just rawhide scales that had broken down in addition to some protective shiny coating that was probably oil based.  In Homer the oil must be worked into the hide by manually bending the leather until the oil is worked into it, also made it soft.Tut's scales are also painted red on one side;  no period paint would stick to oil tan --I don't even think acrylic would.  the red paint would need to be sealed along with the hide or it would stain things.

I do believe the goo is gelatine...

I think there is some suggestion that the egytians used castor/sesame oil for producing their leather, they dont seem to have been particularly enamoured of adopting new ideas in regard to tanning/tawing probarbly because of the dry environment, but there may well be other factors involved commercial/traditional etc.

Leather Work in Ancient Egypt, Veldmiejer 2014

Amosis (Amasis Pharoah) is said by Herodotus to have donated what amounts to a boat load of Alum to the Delphians to help rebuild their temple so it seems to have been available in large quantitys in 6th century egypt, but of course there are many uses for Alum: dying, tawing , medicine , trade etc. as well as the Greeks being able to dispose of large quantitys, but it may just be a case of "beggers can't be choosers".

Theophrastus he of the veg tan references (a very prolific author it seems) apparantly wrote a book specifically on salts and Alum ("Of Salt, Nitre and Alum") but unfortunatly it doesn't seem to have survived (to my Knowledge), but maybe Pliny read it, I think its quite likely?

I think every method of producing "leather" requires manual/mechanical manipulation in some form and often quite a lot, hammering seems to be a very ancient method of getting oil into the skins/hides.
Some thoughts

[Feinman]

Thanks for that Crispianus. I agree.

[Feinman]

Perhaps the answer is right under our noses:
http://www.victorianwars.com/viewtopic.php?t=6811