| It is particularly advantageous to blend judiciously the two main types of material, the pyrogallol and catechol tans. |
| It is the only pyrogallol tannin which does not deposit bloom, or ellagic acid, on the leather. |
| Esculin will not luminesce with peroxidase and H2O2, but pyrogallol or gallic acid will. |
| Also, dilute pyrogallol will luminesce with a dilute solution of oxidizer but not with a concentrated solution of oxidizer. |
| Because of the tanning effect of catechol on emulsion gelatine, it has many of the properties of pyrogallol, including high acutance and low fog. |
| Catechol and pyrogallol may be substituted for hydroquinone, but are not as suitable. |
