General Discussion (Model Railroader)

Texas Zepher wrote:

Here are some clouds I photographed this weekend. They looked like two rows of cresting ocean waves. This photo taken out the dirty windshield of a moving automobile, doesn't do them justice. If anyone had painted clouds like this I would have thought they didn't look real.

Those are called billow clouds.  They're formed by Kelvin-Helmholz instability (that's the instability created by shear across two layers with different stability gradients).  It'd be hard to get into why they look the way they do without delving into fluid dynamics, but although they look like ocean waves they're formed by a different process.

Great shot, by the way.  I'm an Air Force meteorologist working in the field of wave mechanics, and have only seen K-H billow clouds maybe half a dozen times in my life.

Dave Vollmer wrote:

Texas Zepher wrote: Here are some clouds I photographed this weekend. They looked like two rows of cresting ocean waves. This photo taken out the dirty windshield of a moving automobile, doesn't do them justice. If anyone had painted clouds like this I would have thought they didn't look real. Those are called billow clouds.  They're formed by Kelvin-Helmholz instability (that's the instability created by shear across two layers with different stability gradients).  It'd be hard to get into why they look the way they do without delving into fluid dynamics, but although they look like ocean waves they're formed by a different process. Great shot, by the way.  I'm an Air Force meteorologist working in the field of wave mechanics, and have only seen K-H billow clouds maybe half a dozen times in my life.

Ah, you beat me to it!! Another thing I love about being in Colorado on the Front Range are all the great ACSLs we get. The mountain waves can get to be a pain though.

Edit: I was also gonna ask if anybody has attempted a L9 with overshooting tops. I may try this on my backdrop, but not sure yet.

First of all DO NOT PAINT YOUR BACKDROP SOLID BLUE!!!  It varies from blue to almost white at the horizon.  I use two gallons of paint.  One white and one sky blue.  I start the blue from the top and the white from the bottom.  Then you blend them together as quickly as you can.  Streaks are ok.  I then take a four inch brush with  a little white and scrub it into the background to make the cloud.  A two inch brush with a little gray scrubbed in on the bottom and you are done.  It is like evrything else in the hobby. Impossible if you don;t try and fairly easy once you do.  I experimented with a cardboard box to develop my technique.  Easily disposable and good practice.

ndbprr wrote:

First of all DO NOT PAINT YOUR BACKDROP SOLID BLUE!!!  It varies from blue to almost white at the horizon.  I use two gallons of paint.  One white and one sky blue.  I start the blue from the top and the white from the bottom.  Then you blend them together as quickly as you can.  Streaks are ok.  I then take a four inch brush with  a little white and scrub it into the background to make the cloud.  A two inch brush with a little gray scrubbed in on the bottom and you are done.  It is like evrything else in the hobby. Impossible if you don;t try and fairly easy once you do.  I experimented with a cardboard box to develop my technique.  Easily disposable and good practice.

That is a good point. With a weather background (Air Force weather myself), I am thinking about more than just painting some fluffy white "things" on a solid blue background. My grandma hasn't painted in years, but I am going to see if she won't paint me a background. A few paintings she has done is based on the area that I am modeling, and she always had a good grasp of what things should look like "aloft".

I've been researching this very thing, painting clouds... that is.  I painted my backdrop a solid sky blue and that is the first thing I've got to correct.  Skies aren't blue from high overhead down to the horizon.  I'm going back with a can of white paint and paint all of the area near the horizon.  It looks like I'll have to repaint the blue area at the same time and try to blend the two together.  The problem is the fast drying time of flat latex wall paint makes it difficult to do the blending part.

Anyway, after that is done I think I'm going to try the natural sea sponge method of dipping a little of the sponge in white paint and then dabbing it on the background for the cloud effect.  You also keep a piece of cheesecloth handy to lightly dab the clouds to blend them and soften their edges.  Twisting the sea sponge this way and that between 'dabs' supposedly varies the shapes of the clouds and does away with the uniformity I see in a lot of model railroad backdrops.

On the other hand, I've thought about going to the local community college and hiring a starving art student to paint the dang things for me.     

JaRRell

No actual clouds yet, but the first layers of sky blue, light sky blue, and faded blue have been applied. The clouds will be added next. This background is painted on 1/4" hardboard with flat interior latex paints.

I depends on the time of year that you are modeling.  We are doing spring time in the Pacific Northwest.  I painted blue and my husband is the artist.   He painted the clouds.

He started with white using a 1 inch brush and gradually stippled darker gray.  He used the clouds outside the window for a reference.

Sue