Frequently Asked Questions

What is grain damage and how does it show?

Damage can occur by separation tendencies in the hide, causing large sections of wool to fall out during the dressing process. In order to understand how it happens, some knowledge of the structure of leather is helpful.

Leather consists of three layers: dermis, cutis and epidermis. The dermis is removed before tanning. The epidermis is kept intact during the dressing process. Hence, these layers are not involved in this type of problem.

Only the cutis layer is tanned. This layer is vital to the quality of the skin. The cutis consists of two layers. The lower on is the reticulate layer, the upper one the so-called grain layer, often called the grain.

When dressing fur skins, the reticulate layer is thinned out as much as possible. In one of her theses, Dagmar Engström, former Chief Chemist at Tranås Skinnberederi, wrote: “In some species, the reticulate layer and the grain are very loosely connected and can easily be separated. This phenomenon is called double leather. If animals grow quickly, this may be a cause of the double leather effect. This tendency seems to be on the increase, since the highest possible weight at slaughter is desired.”

A theory

When the largest dressing company in Norway experienced problems with grain damage, it was thought that rapid skinning at abattoirs was causing or was a contributing factor to skin damage.

Since the damage is more frequent in skins from lambs slaughtered early, we therefore assume that damage can sometimes be caused by a combination of rapid growth, skinning method used and the speed of the skinning procedure.

How should skins be salted? What kind of salt should be used?

When the skin has been removed, it must be allowed to cool down. This will take about half an hour. Then 3-5 kg of coarse salt, eg rock salt, should be applied on the leather side. NB Do not use road salt!

Chromium – is it dangerous?

The very word ‘chromium’ often causes anxiety in non-expert circles. So let us explain.

At Tranås Skinnberederi we mainly use chromium sulphate as a tanning agent. This is a harmless ‘green’ trivalent chromium salt, which has been used for 150 years by 85-90 per cent of tanneries around the world to produce supple, easy-to-wash skins. It leaves no chromium residue in the wool, and the existing chromium is locked into the leather.

So it is completely harmless, or it wouldn’t be allowed. No adverse effects have been found in products tanned using trivalent chromium. Chromium-tanned leather is used for leather furniture, leather shoes, bags, belts etc.

One cause of confusion is that in debates no distinction is made between trivalent and sexivalent chromium, ie the type of carcinogenic agent that has been commonly used in the spray-painting industry.

What about chrome allergy then?

Yes, it does exist, but is rare. When we created our washable skins some fifteen years ago we discussed the matter with our medical experts. The answer we had from allergists and experts from the National Bacteriological Laboratory was that chrome allergy is very rare and should not be confused with nickel allergy which is much more common. Chrome allergy exists in the same way as one single person may be oversensitive to an individual substance.