I have been scanning objects for years. Using a photo manipulating program (Photoshop if you have big bucks, ACDSee for small budget, Gimp for no budget, you can easily outline the leaf, plus you get to choose the individual leaf or cluster of leafs you want to use, then you can resize them to match the holster, purse, project. Print the leaf on regular paper, lay a piece of plastic wrap on the damp leather, put the design on top of the plastic wrap and use a ball point pen to trace the design onto the leather. You can use the printed image to place vein detail in the leaves. Do the scanning in greyscale. I have scanned the cut leather, then placed the scanned leaves on the holster to see what the final design will look like. This helps with the position of the design for locating snaps and borders.
Seems like a lot of work but the results are worth it. First few times are tough but it gets easier.
