5.4.2 Clouds

Prototype Information

In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space.Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature.
 

While clouds appear in infinite shapes and sizes, they fall into some basic forms. From his Essay of the Modifications of Clouds (1803), Luke Howard divided clouds into three categories: cirrus, cumulus, and stratus, plus a fourth special type, nimbus.

	Cirrus (Cirro-form) The Latin word "cirro" means curl of hair. Composed of ice crystals, cirro-form clouds are whitish and hair-like. There are the high, wispy clouds to first appear in advance of a low-pressure area such as a mid-latitude storm system or a tropical system such as a hurricane.
	Cumulus (Cumulo-form) Generally detached clouds, they look like white fluffy cotton balls. They show vertical motion or thermal uplift of air taking place in the atmosphere. They are usually dense in appearance with sharp outlines. The base of cumulus clouds are generally flat and occurs at the altitude where the moisture in rising air condenses.
	Stratus (Strato-form) From the Latin word for "layer", these clouds are usually broad and fairly wide spread, appearing like a blanket. They result from non-convective rising air and tend to occur along and to the north of warm fronts. The edges of strato-form clouds are diffuse.
	Nimbus (Nimbo-form) Howard also designated a special rain cloud category which combined the three forms cumulo + cirro + stratus. He called this cloud "nimbus", the Latin word for rain. The vast majority of precipitation occurs from nimbo-form clouds and therefore these clouds are generally the thickest.

The WWSL
 

In an online clinic I watched, the lecturer remarked that “there are no bad clouds”, suggesting that a modeler can’t really screw up a cloud – just look skyward at the huge variety of clouds. That lecturer certainly didn't know me !

The WWSL scenery rule is simple: I see the trees not the forest. Scenery is primarily close up. The majority of my sky is not seen, particularly on the lower level of the layout and what is seen is the look of a cloudless, sunny September day in western Washington. This suggests my cloud modeling would be either nothing or at best cirrus type. 

 

There are three locations on the WWSL that have backgrounds that have distance, and require some type of cloud formations:  Satsop River, North River and Headquarters Junction.

Satsop River. The Satsop River Section is on the upper deck of the layout. It is a 'vignette' section and it will have a stratus and nimbus cloud types suggesting inclement weather. I will be using the stencil technique.

 

Headquarters Junction. Headquarters Junction is on the upper deck of the layout. The open space of this section shows distance and will need some distant, cirrus cloud types. I'll try my luck with the Bob Ross method.  

 

North River. The North River Section is on the lower level of the layout. The open space of the river valley will need some distant, cumulus cloud types. I will be using the stencil technique.

 

Modeling Information

There are several modeling techniques when it comes to creating clouds.

 

Hand Painting Technique. The Bob Ross method. Bob uses a palette to hold his paints and for blending the sky blue colors, darker towards the top and lighter towards the bottom.

 

Stencils. Miles Hale published an article in the Railroad Model Craftsman. He designed and cut stencils from poster board of various cloud top and bottom formations. These stencils are then held about 2" in front of the backdrop and clouds are lightly misted-in using a spray can of flat paint. stencils. The stencils can be creatively used (for example overlapped) to get interesting effects. 

Rules of Thumb. The references I've used suggest the following for cloud development:

• The closer to the horizon the cloud is, the smaller it should be. Addditionally, the closer the cloud is to be to the horizon, more blue should be added to the cloud white paint.
• Clouds are objects, so they generally have a shadow on their underside unless they are high altitude clouds or thin and very wispy. That suggests multiple colors for good cloud shadowing, and learning to blend colors using the Bob Ross 'wet on wet' technique.
• Use photo references to make the clouds more realistic. I am using a number of photographs to assist me in the development of the WWSL, particularly for several 'vignette' locations. I have sky/cloud pictures for each section as photo references.
  

Project Process

Satsop River

 

 

1. I created two stencils. See 5.4.2.1 for my stencil construction design and construction technique.

2. Colors. I am using rattle can paints for this cloud build. The colors are Krylon Titanium White for the whitish stratus clouds, and combinations of Krylon Deep Gray, Shadow Gray, Misty Gray, Ivory and Dull Aluminum for the nimbus rain clouds.

3. I used a spray can handle, available at paint stores.

 

4. Cloud painting starts on the premise that you work from back to front and top to bottom,that is from the farthest clouds to the nearest .

North River

1. I used the same two stencils created for the Satsop River Section.

2. Colors. I am using rattle can paints for this cloud build. The colors are Krylon White, Brilliant White and White Onyx for the stratus clouds. 

 

3. The technique is identical to that used on the Satsop River section.

Headquarters Junction

1.

2. Colors.


3. Using a sheet of pallet paper and a pallet knife I thinned out a large amount of Titanium White with Matte Medium and a bit of water. I then applied the paint to the backdrop with a large soft bristled brush in long horizontal strokes. I placed most of the clouds near the bottom of backdrop and created fewer, larger clouds as I worked my way up the backdrop. This helps to simulate depth in the sky.

After the paint dried, I went back with a slightly thicker mix of Titanium White and Matte Medium and added a few puffy areas on the tops of the clouds to add a bit of definition. Supplies

Modeling Information

First paint the sky blue. In both my skies I added deep grays to create the ominous approaching thunderstorm using both the roller and a 4″ paintbrush with bold random strokes.

 Modeling Information

Clouds are very difficult to do well. But a very successful method is to use cut out profiles and spray tones of white and gray using aerosol flat acrylic paint. This method has been described in the Gazette. In my first layout, I used white on the roller, pressed most of the paint out and applied it in a dry brush method using the outer edge of the roller, maneuvering it around to create cloud outlines. Experimenting a little first on a piece of scrap material helps. On my new layout, I used sponges to daub the cloud formations using a fine sponge for makeup.