Characteristics of Non-tannin, Tannin & Gums:
1. Non-Tannin:
- Molecular weight is <500 dalton.
- Less or no-tanning capacity.
- Less astringency.
- assist to penetration into pelt.
2. Tannin:
- Molecular weight is 500-3000 dalton.
- High astringency.
- Have tanning capacity.
3. Gums:
- Molecular weight is >3000 dalton.
- Undesirable & surface reaction only.
Tannin/Non-tannin ratio (T/NT ratio):
1. When T/NT ratio is > 1.
- High astringency.
- Good tanning.
- Use for self-tanning.
- Rapid penetration.
2. When T/NT ratio is < 1.
- Low astringency.
- Mellow tanning
- Use for Re-tanning.