One of the questions posed to me frequently is “how did you get it to look so old? I know that this piece is new, but it looks like it’s been around forever!”
A lot of the techniques listed previously in regard to applications of dyes will weigh heavily on how much you are able to speed the aging of a piece. For example, if you apply a wax or protectant, it will protect your piece from weathering as one would expect. If you do not want your piece to age, do not use a protectant or sealer.
In its simplest form, aging a piece is forcing upon the leather the same situations that would happen to it throughout its lifetime in a shorter period of time. With the water based dyes that I use today, I have noticed that there is natural fading that can occur rather rapidly. To fade the color that has been applied, or to reintroduce damage from ultraviolet light, you can take a finished piece of leather and simply leave it in a sunny place during the day time. If it is damp outside, but still warm and sunny, you will also see some natural curling of the edges of the piece.
To add a bit of crunchiness to leather, you can baste it in salt water. This will give you a sea worn look that is difficult to emulate by dye alone, as the darkening of the leather in lower recessed areas will begin to take on a more rugged feel. When combined with sun, it will also accelerate the discoloration process to mist or baste every half hour or so during peak heat. The leather will begin to take on a work appearance within a couple of days that emulates years of use on the field or in daily use.
For solid pieces, I generally will throw the leather on concrete and stomp on it, pick it up and move it to a different place, then repeat the process. This gives a beaten appearance to the leather prior to tooling so that it will have more pitted recesses and scars to it initially with minimal effort. Antiquing a piece that has been beaten up prior to tooling will pick up these low lying indentions quite nicely. Hitting a finished piece with a stick will gradually give indentions, but they will not do very much for you, since the dye has likely already been applied.
Regardless of the aging of the piece, make sure to seal and condition it after it has gotten the appearance that you were trying to emulate. Conditioning and sealing the piece will ensure that it will get less damage through use after you are done working with it. Make sure to let the piece set for several days prior to actual use, especially if additional exposure to moisture has been used in the process.