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Mar 9, 2011

Chapter 3 - Light Shadow Effect

When finish painting a model, if you want to add more realistic feeling, then special effects are must-have, for instance, adding shadow…

Calculation of Light Source Direction
Before you proceed, you need to measure the facing direction and pose of the model. Giving a simple example, a cube, as showed on the left, if the light source is at the direct front, the surface 1 should be the brightest, and surface 2 receives less light so it’s a bit darker. Next picture illustrates a little more complex case of a shoulder piece, the gray area indicates shadowed area.

You may want to ask: There are natural shadows at those dark areas, so why it’s necessary to create artificial shadows there? The answer lays on the scale of the model, because model is a miniature version of supposedly much bigger figure, hence its shadow which produced by natural light would look quite fake, and so the whole model looks unrealistic like a cheap toy. One solution is to increase the brightness of the light, preferably spot light, to increase the difference between bright and dark surface. However this method is not an easy job, plus the extended period of time intense lighting can cause discoloration of the model painting. Another solution is to make artificial shadow to enhance the bright-and-dark contrast. Insightful readers might have figured it out already: The size plays a vital role here, the smaller the model the darker its shadow making must be.

To find the perfect extent of darkness for a model, obviously you can calculate it out with some rocket science physics equations (Lol~), or more practically, just learn by trying.

Selecting Color
After picking which surfaces needed shadow making, you can move to selecting color. Personally, I often use the base color with a tiny amount of black color paint. Please pay attention not add too much black color, in most cases one or two droplets will do trick, as exceeded amount would lead to great contrast between the shadow and base color, and color saturation (The intensity of specific hue) is also reduced dramatically to the point not appealing to the eyes. If the base color is snow white, you can directly look for [Smoke Gray] to be the shadow color. Because Smoke Gray is a semi-transparent color, by spraying it on the surface, you get yourself a nice shadow effect while preserving the base color. The density of paint should be the same to the most regular cases, please go to Beginner section for more details.

Airbrush Setting
Because shadow creating are mostly on small narrow surface, so adjust paint volume to low and choose small airbrush for better and easier control.

Some would work on the finished model directly to make shadows, others would disassemble those parts first and just paint on each one of them. Whichever approach you prefer, they both work great and better than the other one in some cases. Normally, if the shadow making is done directly on the entire model, the transition of color would look more natural; yet some parts with area that will be blocked after assembled should be painted individually. So you need to plan carefully before you proceed to painting.
Final tip, there should be no clear cut edge of any shadow, so maintain a minimum distance between the surface and your airbrush’s tip (I’d recommend 15 cm at least), and don’t move too slow, otherwise you will leave a apparent trail of shadow boundary.

Chapter 2 - The use of masking fluid

Normally masking fluid is applied to conceal the unpainted model surface. Yet this time I will show its usage in the situation of joining and painting.

First of all, the masking fluid can be used as putty: Since it’s hard to polish any soft plastic surface, both gates and parting lines on this kind of surface can be easily concealed by masking fluid. The joint shield in the first picture looks like covered by a piece of cloth, which is actually done by multiple-layer masking fluid, and the result looks pretty smooth and clean. The other two look like works of a rusty hand, because they were finished as rush jobs by me for showing in this article.

The mixture of Mr. Hobby masking fluid and oil-based paint, it can be used as super dense model paint. This “Special Paint” can easily be mixed to achieve my desired colors, with high stickiness and quite good elasticity, it’s an applicable paint to soft plastic surface. The bottom two pictures illustrates applying the super dense paint onto the protective layer on the griffon’s waist, notice it’s very resilient and doesn’t crack when bent. That’s more than enough for display purpose models. Personally I believe the mixture ratio between masking fluid and model paint can affect the degree of stickiness and softness (The ratio used for illustration was approximately 1:1). And diluted by rubbing alcohol or solvent can change the result as well (As my personal preference, rubbing alcohol is a better option to dilute masking fluid and water-based paint, because masking fluid comes with gloss look, and rubbing alcohol can change the mixture to a dull look, whereas diluted by solvent produces more glossy result).

People asked me about the rub resistance of masking fluid, which I’m still have no solid answer for. It’s because most models I built are for display purpose only, therefore they seldom get changed poses or moved at all, and there is no telling if they are good against rub and scratch.
But I think the mixture of masking fluid and paint (Ratio 1:1) is about equal to regular masking fluid in most quality aspects. Meanwhile thanks to the great density of the compound, applying it normally generates very stick layer, so logically I reckon it should be excellent to be protective against damage. But on the other hand, regular model paint layer can wear off as time goes, or tiny pieces of the layer might fall apart by minor collision. In the case of masking fluid, once tear out a corner, instead of one piece the entire layer will be ripped off.

The griffon model showed in those pictures, the blue paint layer on its waist has been ripped off by my entirely couple of days ago, so it’s back to its original surface again. Just I stated, I started by ripping a small corner, then the whole thing followed, the entire process took no more than 3 seconds. So if you accidentally grind on masking fluid, the grinded area will not become thinner but produce a bubble, and it will spread later. As for scratch, because paint is blended with masking fluid, so it should be good against scratch. Everyone is welcomed to give it a try to see how resistant the layer can be, and the worst case scenario can happen is ripping off the whole layer!

P.S. Special thanks to Jackson for coming up with creative way to use masking fluid. Because this method is still experimental, Jackson admits there is room for improvements, but also it provides an option for model fans to deal with soft plastic surface painting. I recommend everybody to try this, and feel free to let us know if you have better ideas and suggestions!

Chapter 4 - How to use Poly Putty

Poly Putty is a filler frequently used in model building, which mainly serves purpose of filling and pose making.

There are times we try to achieve a certain pose or appearance of a model, that we intentionally change the shape or model parts to make it happen. And that’s why we need poly putty, because its quality exceeds many model putties (For instance Tamiya Basic Gray Putty), in the ay it can be easily shaped and dries very quick. But not without its shortcoming of loosened joining with model parts and also potentially easy to crack.

How to Use:
Before you use the Poly Putty, it needs to be mixed with catalyst. Get Poly Putty (Brown color) out, then add a small amount of catalyst (Red color),
to blend them together, use a toothpick or swab to fully mix them together, after thorough blend it’s ready to be used for adding; Directly apply the Poly Putty onto the designated surface, because it hardens really fast, so don’t have to pause long before start drafting cuts, we use pencil to draw lines to plan the sculpting, wait for roughly 5 minutes then begin cutting, the process is considerable easy because Poly Putty is not fully hardened so it’s still soft,

take advantage of this status to remove all unwanted putty chunks. Another 10 minutes would make it completely dried, it’s the time for polishing, the technique is nothing different from regular polishing for model craft, after this step we can still easily add more texture details on it, tools like etching needle are suitable for this process. And we can recreate all details if we want to change the shape and pose.

Safety Reminder:
Please keep sufficient air ventilation and be careful with fire, because Poly Putty is a slightly volatile substance, and inhale it constantly would be the same as oil solvent, which is potentially dangerous to health. And this putty is also quite inflammable, so keep in mind to stay away from fire for your own safety.

Poly Putty vs. Other Fillers:

Compare with regular putty, Poly Putty hardens much faster and it doesn’t shrink after dried; Compare to Epoxy Putty(Mixed putty), Epoxy Putty is hard to polish on after dried because the hardness, but Poly Putty is easy to polish. As for Polyester Putty & Moli Moli, all three are quite similar in quality and how to use,

the only major difference is that those two are branded specifically for model building, so they are substantially cost more than Poly Putty.
But taking both the price and quality into account, Poly Putty is a pretty good balanced choice of putty.