By Craig Bisgeier
(This article is currently under development, check back for updates soon.)
Backdrops are a tough subject in model railroading. There are as many ways to approach it as there are modelers, from a basic blue skyboard to elaborate photo-realistic collages and low-relief background structures. A sparse backdrop won't harm a layout's appearance much, but a really nice one can help make it come alive -- or even overpower it by becoming a distraction. Choosing what to do, how much to do and how to do it are perennial questions every layout builders faces.
My personal preference is between the extremes, a suggestive approach that represents the sky and countryside without being super-detailed. I like a backdrop that gives you an idea of the setting where you are without being distracting. My goal is to keep my operators focused on their trains and not examining the backdrop to find the endless details hidden in it, and at the same time give them a feel for the land and the era as the pass through it.
As I planned my layout some years ago I kept an eye open when I went to visit other layouts, to see what I liked. Over time I realized I liked painted backdrops the most, as they came closest to my ideal criteria. But I had never learned to paint artistically, and thought the process would be beyond my talents. But one lazy Sunday afternoon as I channel surfed the television, I came across a program that changed my outlook and convinced me that I - and likely anyone else - could do a creditable job painting backdrops.
Nearly everyone has seen the Bob Ross "Joy of Painting" show on PBS at some point, everyone jokes about the "happy little clouds" and "happy accidents" cliches he talks about. But beneath the silly aspects of the show, the man actually has developed a technique to teach useful painting skills that nearly anyone can master with just a little practice and a few basic, inexpensive tools. Not everything he does in his paintings is useful to us for backdrop painting, but if you watch several episodes you will start to take bits and peices that can be used to make some amazing backdrop images that will impress everyone.
It is my aim in this article to try and 'bootstrap' you to a place where you can get started trying to paint your own backdrops as I have learned to do. It requires only a minimal investment in paint, supplies and brushes to get started, and you can be creating wonderful vistas on your backdrop in a very short time. Let's get started by talking about the materials you'll need:
Let's start with the brushes first. You'll want to get a few decent-quality brushes to start with. Don't just try this with chip brushes or the leftover paintbrush you used to paint the bathroom last year, you won't be happy with the results. Craft stores like A.C. Moore or Michaels have everything you will need, and you can get all the brushes you must have for around $25 - 30. If you prefer to shop online, Jerry's Artarama has everything you will want at good prices. You don't need the best, lower tier will do, as long as they are made for oil painting.
You will need:
a 2" straight brush,
a 1" or slightly smaller round brush,
a small to medium sized fan brush,
and a small palette knife.
If you have a little extra to spend get a second 2" brush or a 1" straight brush, it will come in very handy for some things. If you find you like the technique you can always add better brushes to your art box later. A 3" brush can also be handy during the prep stage, as you'll see below
If you aren't sure what to buy, most craft stores have a small Bob Ross section where they sell his books and brushes. They are good but expensive. See what they look like, then go down the aisle and buy something similar for less.
You'll need some sort of palette to hold your paints and mix them on. I use an old piece of Masonite, you can use a plank of wood or whatever. If you want you can buy a real artist's palette.
The paint you select is important. The technique works best with firm oil paints, runny ones won't work so well. There is a line of Bob Ross paints you can use as well as the tools. They will work great but are very expensive. For a less expensive alternative, I've had good luck buying the Windsor & Newton 'Winton' brand of paints. They are moderately priced and work well for me, but I do not have a great deal of experience. Ask someone at the store for a recommendation, or another customer shopping in the aisle.
You do not need every color Bob Ross uses to start off. Get small tubes of the following colors:
Prussian Blue (for Sky)
And any others you feel you might need or want.
You may want to buy a larger tube of the Titanium White, because you will be using a lot of it if you do more than 3-5 feet of backdrop. It's cheaper to buy the large tubes per ounce than the smaller ones, but for the other colors a little goes a long way. A second advantage to having these paints around is that they are great for weathering structures and railcars. Google the name Mike Rose and check out the work he does with these paints. You'll find them useful for more than just your backdrop.
If you've ever watched the Bob Ross program, you'll know he always starts off coating his canvas with something he calls "Magic White", or Liquid White. Don't bother looking for it because you won't find it anyplace except in the paints with his name on them. But all is not lost, it turns out that Magic White is nothing more than good old Titanium White mixed with Linseed Oil to thin it down. Buy a small can of this and use it to make a batch of Magic White when you are ready to start painting. This is also why you'll be using a lot of Titanium White, as I mentioned above.
You will also need to buy some odorless mineral spirits. This can be found in the paint aisle of your home center or at the craft store. You'll need this for brush cleaning both during and after the painting process. An old coffee can works nicely to store some in while you work and can be sealed with the plastic lid when you are done. If you can fit a bit of chicken or mesh wire in the bottom to scrub the brush as you clean it, so much the better. You'll also want a tall trash can to shake the brush off in, and some paper towels handy.
Prepare for Painting
Few of us will actually be painting on canvas. We use all kinds of backdrop surfaces on our model railroads, from Masonite to styrene to metal. Whatever you use, you'll want to get at least one coat of white primer up onto it before you start, and let it dry thoroughly. Porous surfaces like Masonite will probably require two coats to seal it. Use real primer, not leftover white paint from your kitchen. It makes a difference.
Get your materials ready before you start. Pour some mineral spirits into the coffee can, lay out your tubes of paint and your brushes where you can get to them easily. Get a roll of paper towels, your palette and your trash can handy. I put everything on top of a roll-around plywood cabinet so it's accessible. Make sure you open a window or two and get some ventilation going. The fumes aren't toxic but some people find them objectionable, fewer still are actually allergic. I also paint with a pair of latex rubber gloves on and a smock because I tend to get messy even when I'm trying not to.
Start out by mixing up your Magic White. Squeeze out a bunch of Titanium white paint into a dish and add about 10-20% by volume of linseed oil to it. Mix it us with a Popsicle stick or your palette knife until the chunks are stirred out of it and it is a smooth and creamy consistency. You'll need enough to cover the entire section of backdrop you will be painting in this one sitting. I usually only work on one section about 8-12 feet long at a time. Don't mix up too much, it will go to waste. This stuff takes a LONG TIME to dry, so if you don't mix enough the first time just go back and make some more. It'll wait.
The last step of prep it to start laying the magic white on the backdrop. Use your largest brush, probably your 2" or bigger if you bought one. A larger brush will make this task go faster. Start in one corner and apply the magic white in long horizontal strokes, covering the area completely with paint but not leaving any thick wet spots. When the horizontal strokes are done go over it again with vertical strokes to ensure the surface is completely covered. I usually work an area about 2' wide at a time, them move over and do another 2 feet.
When the entire area is covered with magic white then you are ready to start painting.
Basic principles of Wet on Wet painting technique
|Keeping a few things in mind while you start to paint will help you do a good job and paint a realistic and believable backdrop.|
|You will work from far to near. Start with the things farthest from you, and slowly work up to the things in the foreground. Sky and clouds come first, then distant mountains and hills, tree lines, grassy hillocks and groups is indistinct trees, structures, and foreground trees.|
|If you plan to have water, the reflections will go in at the same times the objects that are reflecting do.|
|If you make a serious mistake, chances are you can scrape off the paint with your pallette knife around the actual mistake, then go back and refill the area from back to front again. for less serious boo-boos, it should be very simple to cover it with a cloud or a tree later. The technique is very forgiving.|
|On the Joy of Painting series, Bob Ross often sets his horizon line (where the sky meets the ground) about halfway up his canvas. For backdrop painting, you will probably want to pull that down to less than the bottom third or about a quarter of the height of the backdrop. That figure can change depending on your layout height and type of scenery being represented, but in most cases youíll want it low for better realism. That doesnít mean some hills and mountains canít project above that line, thatís fine. What it does mean is that your viewing angle of the scene should look as though you are|
|As you reach the foreground, you will often be laying down a darker color for foliage than you would expect. Trust the technique. You will be going over it again with brighter highlight paint shortly. The dark areas become shadows under the lighter areas which help pop the colors. It will look good in the end.|
|Overlapping things as you move from back to front gives the impression of distance and depth. Don't be afraid to put in a distant tree line and then cover most of it up in the next step.|
|Many water effects require you to be able to move the brush or tool in a vertical or horizontal line to work well. You may need to practice this a bit before actually trying it on your backdrop.|
|No matter what you are doing, remember that a little less is better. If you are doing something like blending and see how it starts to look good, STOP. Doing too much, even just a little, will often ruin the effect. Resist the temptation to do just a little more.|
Important Differences for Backdrop Painting
|I highly recommend that you make time to watch a few episodes on the Joy of Painting series. It is still shown on some broadcast PBS stations, and regularly on some of the PBS cable stations. TiVO is your friend here, makes it easy to find and record the show so you can watch it later, but a VCR and the internet can turn up airings as well. I describe many of the techniques as well as I can, but seeing Bob Ross do his thing is worth thousands of my words.|
|On the Joy of Painting series, Bob Ross often sets his horizon line (an imaginary boundary where the sky meets the ground) about halfway up his canvas. For backdrop painting, you will probably want to pull that down to less than the bottom third or about a quarter of the height of the backdrop. That figure can change depending on your layout height and type of scenery being represented, but in most cases youíll want it low for better realism.|
|That doesnít mean some hills, mountains and structures canít project above the line, thatís fine. What it does mean is that your viewing angle of the scene should be flatter, as though you are standing on the ground near the bottom of the painting. If you have a high horizon line it will look like the ground behind the railroad is on a steep incline, ready to fall out of the painting onto the layout. For low layouts that may be OK, but the higher the layout gets to eye level the horizon line should dip lower and lower.|
|Itís also important to note that we donít want to use all of Rossí techniques. We want our backdrop to be in scale with the scene it front of it, or smaller. Most of the techniques early in every show are useful in one way or another, but in general anything shown after the first 15 minutes have passed is going to be too large and out of scale for our needs. Keep this in mind as you watch the show, and take notes on the ideas you can use, and those that wonít work for you.|
Sky and Clouds
There are dozens of ways to paint the sky and clouds, just watch Bob Ross on TV for a week or two and you'll see ten different ways to do it. The following is how I do it, based on several ideas I picked up from the show:
Squeeze out some Prussian blue onto your palette, and grab your clean 2" brush. Load the brush with paint by tapping it into the paint vertically about 8-10 times. Start in an upper area and holding the brush perpendicular to the backdrop, start making criss-cross strokes about 3-4" long and overlapping as you get paint onto the backdrop. Do not worry too much about blending it all together at this point. As the blue starts to mix with the white, move the brush down lower and lower down so the blue becomes paler and paler. When you reach the bottom, go back and load the brush up again by tapping it into the paint and work your way over to the side a bit. Again, start at the top and work your way down as the paint gets paler. Clean the brush from time to time in the coffee can, and shake out the excess mineral spirits in the trash can. Wipe the brush on a paper towel, then load it up with paint again.
Water effects: Anywhere you want to have water, take the dirty brush with blue paint on it and streak it back and forth along the lower part of the backdrop where the water will eventually be. Work your way up from the bottom with the color so the horizon line is paler than the bottom. Keep these strokes as horizontal as you can.
If you wish to have clouds in the sky, leave some areas white, do not cover them with blue paint. I try to leave about 20-30% of the backdrop white in random spots and shapes, which will make a fairly overcast sky. If you want fewer clouds, leave only about 5-10% of the backdrop white in random spots.
Once you have your blue paint all over the working area, Start working on blending the sky together. Go back to the beginning and continuing to use the criss-cross strokes, work on blending out the brush marks in the sky and trying to make it more even and fluid. It does not have to be perfect - some variation will look like faint clouds in the distance. It's OK to blend some of the blue into the bottom of the white edges if you have clouds, but leave most of it at the top white.
When you are done blending, clean the 2" brush well and squeeze out some Titanium White onto the palette. Load the brush by tipping it back and only tapping the bottom corner into the white paint. Bring the brush to a white area, holding it at the same angle and following the top edge of the white, move the brush in a tight circular, overlapping spiral motion and paint swirls of white just over lapping into the blue area. You'll only be able to do 3 or 4 swirls before you pick up too mush blue, so go back and pick up some more white and then do some more along the top edge. It's OK to leave a lot of paint at this point to ensure it covers. Clean the brush frequently as you do this to avoid picking up too much blue and only do the tops of the clouds this way. You can do some additional swirls on the middle-top of the cloud to give it some depth.
Once all the clouds have had their tops whitened, clean the brush again and holding it at the same angle, use the same swirling motion to start blending the undersides into the blue. Go into the white swirls and blend, but don't blend the top edges at all. This will give the tops definition and make the middle and underside less distinct. Remember that most clouds are pretty flat on the bottom. They don't have to be perfectly horizontal but odd projections down should be avoided.
When this has been done clean the brush thoroughly again and go back to fluff the clouds. To do this you'll hold the dry brush perpendicular to the backdrop, and in wide circular swooping upward motions, barely touch the backdrop and draw the extra white paint in the tops of the clouds up and around a bit. This is a very light pass, as Bob Ross says, "Two hairs and some air". When that's done, gently and lightly draw the flat brush across the sky horizontally to finish blending the clouds into the sky. Thatís all there is to the sky and clouds.
Mountains and Hills
If you spend any time watching the Joy of Painting show, youíll see that more than half of the paintings have distant, snow-covered mountains depicted. I will not go into the details of how to do that here, it is covered often on the show and the technique never changes. I will only add that for backdrop painting, you will need to make your mountains much larger than he does in the show. You are working with a backdrop that may be anywhere from 6-20 feet long, where he works on a canvas only 24Ē wide. Use the same techniques, but go wider and taller than he does, and be sure to plan to hide the bottom edge behind a closer hill or tree line to give it depth. Itís important to go bigger and not just make many smaller peaks, it wonít look right. Follow a photo for inspiration if you can. And donít be afraid to paint other things like trees and structures over it later.
More useful to many of us than painting entire mountains for backdrops are creating distant rolling hills. Very distant hills should be done with a purplish color with just a tinge of green, closer in go with more green and less blue/purple.
Decide where the ridgeline will go. Mix the paint on the palette, then take a clean 2Ē brush and tap the top corner into the paint. This is the opposite of how you loaded the brush for the clouds with the bottom corner. Bring the brush to the backdrop and, holding the brush vertically with the top corner pointed down start tapping the brush firmly onto the backdrop, moving to the side a little with each tap. Donít overlap your taps very much. You can vary the height a bit but not too much, there should be very little definition at this point. As the paint starts to run out, reload the brush and continue tapping and working your way to the side. When you get to the far end, do not reload the brush with paint, but tap firmly underneath the ridgeline, going back the other way. This spreads the paint more and creates a misty effect as the magic white blends with the ridgeline color. This will help create depth when you put the next layer on.
Water effects: If you will have a pond, lake or river on the backdrop, decide now about where the far bank if it will be. With the brush holding a little of the ridgeline color, give a few taps below the far shore of the body of water. With a clean brush, hold the brush horizontally and place the edge of the brush at the edge of the riverbank. With gentle but firm pressure, draw the brush straight down to streak the paint down vertically. Do this all along the waterís edge. When that is done, turn the brush to the vertical and sweep it across the water horizontally in wide strokes, taking care to keep the strokes horizontal. This will create nice reflection effects later.
Mix a color that is a grayish dark green for the next hill, this one will be closest. We will put in a middle distance tree line. Using the 1Ē round brush, tap the brush into the paint the same as you did with the 2Ē brush above, getting paint mostly into the top edge. Start tapping the brush into the backdrop to establish the tree line just as you did with the distant line of hills using the top corner of the brush and tapping down firmly. This tree line can overlap part the previous ones if you want it to, which will give a great impression of depth. If you prefer tall narrow trees to rounder deciduous ones, use the top corner of the 2Ē brush instead of the round brush, or use the 1Ē brush. Just as before, tap out the area underneath the tree line to make it look more like mist.
Water effects: As above, tap some of this green color onto the top of the waterís edge and use a clean 2Ē brush to streak it down, and then brush a few horizontal strokes over it.
We are now close enough to start to put on more distinct, somewhat individualized trees. These are not the big foreground trees you often see painted on the show, but those in the background, the ones that make up the back edge of the foreground scene. We will use a shadow and highlight technique here to really make these trees pop off the backdrop.
Start with the shadow color, a darker green (mix in some black with some sap green and a little burnt umber). Using the round brush, load it up by tapping it down into the paint, but donít pick up a lot of paint. Tap the brush onto the backdrop at a slight downward angle, and make some generically round tree shapes about 2Ē around. Donít make the shape completely opaque; leave some bits of the background showing through here and there, and at the edges. Place these shapes irregularly wherever you want trees to go, vary the height some and leave some open areas where a bit of the background can show through. This will not look too good as you are doing it, but stand fast, it will look a lot better soon.
If you want to put in any tree trunks, now is the time. If I include them, I use a dark gray color mixed with a drop of mineral spirits to make it flow easily. I use a small fine brush to draw in the trunk and limbs. Do this sparingly, not every tree needs a trunk to make this work. You can even do without it completely.
Now mix a color of brighter green (I usually try to match it to my primary ground foam color). Clean the 1Ē round brush and tap it gently into the lighter green. With the brush tilted down more than before, gently tap the brush here and there on top of the dark areas leaving small crescent-shaped dabs of paint. You will quickly see that this starts to look like the sun reflecting off the leaves at the top of the tree. Tap here and there sparingly, working from the top down, trying to make it look like there are different bunches of leaves out in the sun. LEAVE SOME DARK AREAS VISIBLE underneath the bright green. If you cover up all the dark areas the trees wonít look right. Less is more here, you need some shadows. Clean the brush frequently as you change from tree to tree. You can add color variations here and there (a little yellow, a little red in with the green) to make the trees each look a little different.
Pines are really easy and fast to make. Get your fan brush out and mix up a dark green color (add a little blue for spruce). Load up the brush with paint by dragging it across the paint back and forth. Align the bristles vertically and draw a thin, straight vertical line about an inch or so long from where the top of the tree will go down. Then turn the brush horizontally and start tapping, making short horizontal lines to either side of the vertical one, and getting thicker and wider the farther you go down. Tap down a bit, allowing the bristles to bend up as you tap which will help make the branch shape look better. Add extra taps in the middle to fill the tree out as you go down. To end the tree just stop when youíve reached the bottom of where you want the tree to end. These trees often grow in clusters, so itís fine to paint in three or four close together with differing heights.
The basic ground form in this painting technique is a grassy hillside. It is pretty easy to do and goes on fast. Youíll need your 2Ē brush for this technique. Like the trees this is a shadow and highlight technique, so donít freak out when it looks bad at first. It will quickly look much better.
Mix up some dark brown color on your palette and start laying it into the backdrop with your 2Ē brush. You donít have to tap here; you can drag the brush across the backdrop and use sweeping side to side motions to rough in the lay of the land. Bring the land up to meet the trees you painted in earlier so they are grounded. If you have water areas, bring the land up to the banks in diving swipes so it looks like the land dives under the water. Donít worry about prettying up the edges right now.
Clean the brush, and mix up some lighter green paint with some other browns and darker greens on your palette. Do not mix thoroughly; you want some variation in the tones as you pick up paint on the brush. Tap the brush evenly into the mottled paint, and bring the brush to the backdrop. Starting at the top of the land, hold the brush perpendicular to the surface and tilted horizontally so as to follow the edge of the land. Tap gently along the top edge, using the bright fresh paint to establish the crest of the hill. Move the brush horizontally down the edge of the hill, and as the paint starts to fade move lower and firmly tap in some more Ďgrassí below it. The effect you are looking for is a bright top edge and a gradually fading color as the hillside moves down and forward. The darker color below will mix with the brighter paint as you move down. Keep the brush aligned with the lay of the land as you tap in the grass. Again, work with the darker base color you have already laid down, donít cover it all up if you can help it.
An effective technique for adding depth to the backdrop is to paint in slightly rolling hills that pass in front of one another. It may not be feasible, but it is something to keep in mind if you have the right type of landscape to make it work.
Water effects: As you are putting in the grass, you want to begin integrating the waterís edge with the surrounding landscape. This will be another shadow and highlight technique. Mix up a dark brown color with a little black paint. Using the palette knife, hold the clean knife edge flat on the palette and drag it through the marbled paint on an angle, drawing a tubular bead of paint on the edge. Use the knife to paint in the wet dirt around the water area by gently scraping the dark paint around the edges horizontally, but dipping down to meet the water.
When you are done with this, take some of the same color and mix in some lighter brown, and marble in a pit of white paint as well. Clean the knife and drag it through the marbled paint on an angle again to pick up a roll of paint on the edge. For best effect, drag the flat edge of the knife gently across the backdrop, barely touching the paint to the surface. It will streak over the darker surface and give a nice marbled effect at the waterís edge. When you are done with this, take a little bit of the Titanium white and with the clean palette knife, pick up a small roll of white paint on the edge. Holding the edge horizontal and flat on the backdrop, move the knife from side to side along parts of the waters edge to gently define the boundary with a slight line of white. You are looking for a very subtle effect, and only here and there.
When this is all done, continue tapping in grass to cover the back edge of the dirt. You can cover most of it if you want to but leave some visible here and there to enhance realism.
To paint stones poking out of the ground or exposed rock faces, follow the same basic technique described above for dirt around the waters edge, but use a grayer or lighter brown set of colors. The motions will also be more vertical than described for the dirt. Practice a bit to see if you can get a look you like. Be sure to plant the bottom in the ground by tapping grass over the bottom edge after the stones have been painted.
At this point you need to start thinking about where you will stop. Folks in N scale may want to stop right here or risk their backdrops starting to look out of scale. Modelers in HO have the option of putting in a few foreground trees but will want to be careful to keep the size in check. In larger scales, refer to Rossí techniques on the show to make some larger and impressive painted trees on your backdrop.
The process for making foreground deciduous trees is almost the same as the smaller, distant ones we made earlier, but these will be slightly larger and individualized. Take stock of the average size of the trees you would normally place against the backdrop, and make a mental note of how high that is. Generally you will not want to paint any trees higher than this, you will want the actual trees you put on the layout to be taller because they are closer to you, and will look more realistic.
Before I start, I work on trying to mix a highlight color Iíll use last that matches the color of the ground foam I use for my model trees. This really helps to blend the backdrop into the foreground and blurs the line where the layout ands and the backdrop begins. Take notes on what colors and proportions you used to mix the color so you can make the color again the next time you paint.
Start with your dark green color and load up the 1Ē round brush by tapping it into the paint. Decide where you want your tree and start tapping in the shape of the canopy with the brush tilted downward so the top edge is hitting the backdrop and nor the bottom. Go sparing with the paint so you donít make an opaque blob, you want some of the colors behind to show through some. Continue tapping in tree shapes here and there where you want them.
You can apply tree trunks on these trees now if you like. As I said before I prefer dark gray with a touch of brown as a color. Mix up a small amount and include a drop of mineral spirits to make it flow smoothly, and paint in the tree trunks and a couple of larger limbs. It you want to include any dead trees now is a good time to do that as well.
Finish the trees by going over the canopy with your lighter green color, applied with the 1Ē round brush lightly loaded with paint and held on a downward angle. Donít kill all your dark areas; you want some leaves in shadow to show through to give the tree depth. Apply the paint sparingly and lightly for an airy, light look. Finish by applying some grass with the 2Ē brush to ground the tree trunks and stop them from floating in the air.
Painting in structures is not very difficult, but it may require a little practice. Understand before you start that this is going to be a rough representation and not a photo-realistic image. It will be nearly impossible to include anything but the most basic of details (doors, windows) and attempting to do so will likely make the item look out of place on the rest of the painting.
First, itís best to work from a sketch or photo instead of freehand from memory. Decide before you start how large you want the structure to be and where it will sit, then use the palette knife to scrape off the wet paint where the structure will actually sit. Only scrape areas that the structure will cover. Scrape in from the edges to the center. It does not need to be perfectly clean.
In most cases, youíll see two sides of the building in your painting. Mix up the color of the building and decide which side faces the sun. Load the palette knife with paint by drawing the edge across the paint. Starting at the top edge of the place the building goes with the blade horizontal, draw the knife down spreading the paint evenly down the area. If the structure is wider than the edge of the knife, re-load the knife and move it over, and draw it down again to fill the void.
To paint the wall in shade, mix a little black or blue in with the original wall color evenly and perform the same draw-down technique. To paint the roof, mix your roof color (likely black or gray) and pick up the roll of paint on a clean knife. Starting at the ridge line, draw the knife down diagonally to shape the near edge of the roof. Repeat until the roof is laid in, and then use the edge of the knife to paint in the edge of the far side of the roof by dabbing it gently against the backdrop.
To paint in windows and doors, scrape an opening into the wall colored paint and load the short edge of the knife up with black or dark gray paint by drawing it across the paint on the palette. Fill the openings with the dark color using the same draw-down technique you used for painting the walls. Donít be afraid to experiment, I have also used screwdriver tips and plastic strips to fill in smaller voids where the palette knife would not fit. Be sure to go over the bottom edges of the structures with grass or dirt techniques to plant them in the ground, otherwise they will appear to float over the scene.
If you want your structures to show more detail, watch the Joy of Painting show for more ideas on textures. Personally I believe Rossí weathered wood techniques are out of place for anything but G scale, but to each his own.
The only real downside to oil painting is that it takes time for the paint to dry. Not a couple of days or a week, it can take up to a month for it to completely set. The upside of this is that if you need to stop working, you can go back and continue to work a day or two later with almost no consequences. But when it is finished you must leave it undisturbed for a considerable length of time, and it will stink a bit until it does dry.
But it turns out there are products sold in the craft store that dry the oil paints faster if mixed in with them. I worried It might make the paint slightly less firm which could be a problem for this technique. But I have successfully mixed it in with my Magic White when I make that, and it really does work -- The last time I painted using this drying agent everything I painted was dry within a week. This makes working around recently painted backdrops much simpler without having to worry an errant bump will wipe a streak across your backdrop.
I hope this article has given you the confidence to try painting your own backdrop with wet-on-wet oil paints. It is practically foolproof and easy for almost anyone to do, and the results are very attractive. And as mentioned earlier, oil paints have uses beyond backdrop painting on the model railroad. You can get a lot out of this investment if you look around and make use of it.