And then follows a barrage of opinions and answers like "I have been using neatsfoot oil before I dye for decades.....".
This concept originated decades ago when:
- the leather was tanned with different recipes,
- only alcohol based dyes were available and had very different recipes from the alcohol based dyes of today
- they applied the oil VERY sparingly and let it sit at least overnight to completely even out in the leather
There are a few warnings here:
• All the liquids and their formulas have changed numerous times just in the last 10 years.
• What is seldom mentioned in the answers is the time frame of the applications, the type of dyes used, the specific leather they work with, the quantities they work with, etc.. All of these makes a drastic difference in dying leather.
• A beginner leathercrafter might have horrible results results with a method an old saddle maker has been using for 40 years.
So, first use your common sense. Read the labels of the liquids you use.
TEST every procedure on the SAME leather before doing it on your project. And your test should go all the way to testing that piece of leather for the dye coming off on your clothes (I often carry a piece of leather in my pocket with my keys to see how a dye or finish will hold up).
One of the best pair of books you can read on dying was written by Tony and Kay Laier, one was about Fiebings products and the other about Eco-Flo products.
Search for "Fiebing's Fantastic Finishes Book" by Tony & Kay Laier.
They have been discontinued due to the changes in colors and ever changing liquids, but they are still the best way to get a fast education about different methods of dying.
The book about Eco-Flo dyes are available in digital form at https://www.leathercraftlibrary.com/product/1145/coloring-with-eco-flo-by-tony-and-kay-laier