Our house has several large trees that drop their leaves over the course of a month, making raking them up a multi-weekend project. They start off bright yellow and red but quickly turn to brown. I wondered if I could find a way to have them keep their bright colors but alas it didn't seem possible when using real leaves (ground up colored construction paper might work though). Since most leaves you see on the ground have turned brown, this seemed the best color choice for a basic layering.
Lou Sassi in his book Basic Scenery for Model Railroaders described the process he uses to process real leaves into scenery materials. He starts by taking a handful of leaves and removes the stems and any debris. It doesn't matter if they are already dried leaves or "fresh" ones that have just fallen, but if they aren't dried you better do this quickly or they may start to mold on you. Fill the blender half way with leaves, add water to just color, and set it to medium/high for a minute.
Obviously, don't use your good blender, a good shirt, or a good cookie sheet. My wife found me a nice blender for free on Facebook though it took several months of looking to locate one with a canister bowl. I did it outside on a really warm October afternoon to minimize the mess.
Then, strain the mixture to remove most of the water.
Last year when I did this I used an old T-shirt which worked well but really made a mess and took forever. This year, I just set the watery mash in a metal strainer for a couple of minutes to drain, and then dumped the still-damp leaves into another metal pan.
Next, the recipe says to bake the chopped leaves on a sheet pan in a 200 degree oven. No cook time is listed, but you should move and flip them occasionally to ensure even drying. Leave the oven door ajar a couple of inches to let steam escape.
This year I upped the temperate to 400 and it still took a couple of hours. My house smelled weird (not bad, but sort of like walking through the woods) and my wife didn't really appreciate that. If I had used a t-shirt to wring most of the water out it would have helped.
Once dry, let cool and then filter through your strainers. I have several different sizes which I use when I process real dirt so I used them here too. I found that only one, which has about 12-13 squares per inch, was perfect. The stuff that fit through was just right to look like a leaf in O scale.
The amount of stems left in the leaves is annoying and you don't end up with much of a finished product, but they do look good and are cheap. I just don't have the will power to process a ton this year (and I didn't last year either), so perhaps I will do just a little bit every year and slowly acquire a stash.
