How do colors of vegetable-tanned leather change?
We would like to introduce a report that outlines a research study aiming at verifying, on a scientific basis, the color transformations of the leather produced by the tanneries associated to the Genuine Italian Vegetable-tanned Leather Consortium.
The leather – natural and biological raw material- tanned with vegetable extracts according to the operating standards of our Consortium, can be left natural or can be dyed with various chemicals after tanning. In any case its color will slightly change over time.
The research study, proof of the strong importance the Consortium places on research and development, produced interesting results for the stakeholders of the leather sector with an ever-growing sensibility towards concepts of quality, eco-friendliness and product’s origin.
The colors of veg-tan leather: the results of our test
The image below shows the results of the test; The aim was to obtain a series of samples which were aged artificially and quickly (using a light source) in order to obtain an immediate visual comparison of the various stages of chromatic variation.
The Objective of the study was to test various leather samples by exposing them to light for a certain number of consecutive hours, attempting to reproduce in the laboratory the conditions wich correspond to months or years of use of a handmade leather product.
While analyzing the results, however, a number of variables with regards to usage has to be considered: frequency of use; the amount of ambient light; the number of hours of continuous exposure to light; the number of hours of continuous exposure to heat; humidity absorbed by the handmade product; use of products such as wax and polish.
The results have proven the influence of temperature, heat and light on the color variations. Different changes were noted in the different colors: The color brown showed the most stability, the natural uncolored leather showed the most change, and varying gradual transformations were observed in the yellow, green and blue samples.
These changes, resulting by the aging process, testify that chromatic deterioration diminishes with the passing of time and yet, it is primarily notable during the first two years of use of the leather product. In any case the strong character of the vegetable extracts used in the tanning tends to re-emerge with the time and to affect the color variation of leather towards the brown shades.
Any article made with vegetable-tanned leather – whether a belt, a handbag, a wallet or a shoe – during its slow, natural chromatic change, reveals its charm and its identity, its value and its prestige.