I've had a few of my backdrops in place for a few years, but this month I am installing them en masse. I thought I would share the process.
There are a number of companies that have offered long backdrops on vinyl and other materials, but they tend to be very expensive. Over the past few years, a few companies have come out with CD's or DVD's of backdrops that you can print yourself. Though they require piecing together, the price is right!
Several years ago I discovered LARC Products at a Great Scale Model Train Show at Timonium, Maryland. LARC has six volumes available thus far, and each contains dozens (sometimes hundreds) in each category of landscapes, industrial scenes, buildings, interiors, etc. Some of the landscapes are 10-13 feet long. The first couple of disks were in Microsoft Word format, but I had no problem using Open Office or Apple Pages to open and print them. The last few disks are in Adobe Acrobat (PDF) format.
I print my backdrops on 80-100 pound cardstock on an HP color laser printer. Ink jets may work, but they often have issues with heavier stock. Smearing may also be a concern. If you don't have access to a color laser, it may be worth paying for prints at a Staples, Kinko's, etc. I'll add that the choice of laser over ink has nothing to do with resolution. The fact of the matter is, you don't want your backdrops to be overly sharp, or it draws a viewer's attention away from the railroad.
The prints take into account the border required by most printers. The first step is to trim off one side and the bottom. I only trim one side so that I can overlap the joint between pages. If your hardboard is painted blue, like mine, and there is any gap in the prints, there will be a very obvious slit of blue through the backdrop! The overlap removes that liability. As for which side to remove, I base that on the most common viewing angle. I trim the side away from the viewer. When you overlap the pages, the edge of the top page will face away from the viewers.
I use a paper trimmer for taking the edges off. You could just as easily use a sharp knife and straight edge.
The next step is to trim away the sky. Use a brand new knife blade! For my early backdrops I cut very close to/on the tree line. I have found that precision is not required, at least given my choice of paint color on my hardboard. I cut to within 1/8" to 3/8" of the treeline and that seems sufficient.
I lay down a few paper towels to use as a drop cloth for applying adhesive. I add another paper towel for each new page. You certainly don't want glue on the front of a page! With a page facing down, I give the back side a generous application of 3M spray adhesive. I then pick it up carefully by the edges and take it to the layout.
The adhesive is extremely sticky and there is little play for placement once the two surfaces meet. I carefully align the overlay edge at the bottom, then the overlay top, then confirm that the bottom edge is level. I only press lightly with my fingertips. I then take a crupled paper towel and wipe/patt down the image. This keeps toner off the fingertips, which could transfer to the next page. I replace this paper towel every two pages.
The lead image shows 10 feet of backdrop applied in about 30 minutes along my Lewistown yard.