Say whether the leather is empty or harsh. Empty needs fill. Harsh needs lubrication. The chemicals are on different pages.
Two defects that feel similar in the hand
An empty leather feels thin and tinny. A full but dry leather feels harsh and may crack on the last. The first needs syntan or a filling retan. The second needs fatliquor penetration. Adding oil to the first makes a spongy grain that finish cannot hold.
Esteem’s powder-syntan article is about leveling and fullness. The liquid-syntan article is about neutralization and feel. Fatliquor articles assume the retan is already chosen.
Shoe upper versus garment
Shoe uppers want spring and a tight grain, so fill stays higher and oil stays moderate. Garments want run and fluff, so oil goes up and fill is chosen so it does not board. Upholstery sits between them and adds fogging and heat.
Copying a garment retan onto a shoe upper is as wrong as copying the fatliquor. State the article.
Order of the trial
Neutralization sets how anionic syntans and oils exhaust. If you skip it, both the liquid syntan and the fatliquor will sit wrong and you will blame the products.
Keep percentages on shaved weight and name the samming state. Offers drift when the leather is weighed wet.
| Hand complaint | First change | Second change |
|---|---|---|
| Empty cut | Filling syntan | Then oil if harsh |
| Cracky grain, full cut | Fatliquor penetration | Then top handle |
| Loose grain | Less oil, tighter retan | Not more oil |
| Flat dye | Powder syntan / dispersant | Not a softness oil |
Fullness is filling, softness is slip
A retan syntan, a resin, or a vegetable extract deposits in the fibre weave. The leather gains thickness, break, and a tighter grain because the fibres have less room to move. A fatliquor deposits a lubricating layer so fibres can slide. Raise the retan and the leather gets fuller and firmer. Raise the oil and it gets softer and, past a point, looser and greasier.
The specification has to pick a position between those poles. Shoe upper leather usually wants fullness and a controlled break. Garment leather wants softness and run. Using a garment oil offer on a heavily filled upper, or a heavy syntan on a garment skin, produces the complaint the other property was meant to prevent.
Order changes penetration
Oil offered before or between retan stages can still enter an open chrome leather. The same oil offered after a large syntan or resin sees a partially filled cross-section. Exhaustion on the grain rises, the centre stays firm, and the surface darkens. Staging the fatliquor, which the rechrome and retan notes already allow, is a penetration plan, not a way to increase the total oil without a greasy grain.
Dye behaves the same way. A retan that fills the surface will also change dye levelness. If retan and fatliquor and dye are all new in one trial, the tannery cannot assign the shade or the hand.
What to write on the brief
Name the article: upper, garment, upholstery, or lining. Name which property is allowed to lose if the other must improve. A request for “fuller and softer” needs a target for each, plus the current offers, or the next sample will simply be a larger dose of both.
Keep a cut section in the evaluation. Fullness that is only a swollen grain, and softness that is only a slippery surface, both fail as soon as the leather is dry and staked. The cross-section shows which one you actually built.
How to Specify with Esteem
- Say empty, tinny, or harsh.
- Name the current syntan and the fatliquor offer.
- Change fill first if the cut looks empty.
- Change oil first if the cut is full but cracky.
- Re-dye only after one of those moves, not during it.
Use powder syntans and liquid syntans for fill, and fatliquors for softness.