THE USE OF GELATINE FOR MOLDED PROSTHETICS
(c) 1998, Mitch Boudrot
All Rights Reserved
The information contained within the context of this article is presented in good faith. The responsibility for the use of any material in special make-up effects rests solely with the user. The author assumes no responsibility for the use, or misuse, of any material, technique, or the informational content, discussed within this article.
In the first installment to this series, you were introduced (or depending upon skill-level, reintroduced) to the medium of gelatine (a.k.a. gelatin), and it's historical and current use for three-dimensional make-up effects. The historical aspect of gelatine is essential for an understanding of the medium, and it's eventual evolution and development in the field of special make-up effects. Additionally, the inherent advantages of gelatine over foam latex and other mediums were presented, including its relative safety, cost and ease-of-preparation. For the neophyte or experimenting make-up artist, these attributes make gelatine an ideal medium for gaining invaluable understanding and technical skill for working with three-dimensional prosthetic media. The technical processes involved in life-casting, sculpting, mold making, etc., are beyond the intent and scope of this series. For information regarding the "how to" of these skills, I refer the reader to the resources listed at the end of Installment 1.
In this installment, I will present specific gelatine formulations, a discussion of formula components, and an example of molding gelatine for the production of prosthetics. Again, this series of articles is by no means the most complete treatise on the use of gelatine for molded prosthetics. Rather, it is intended to provide information to make-up artists and enthusiasts, interested in experimenting with the medium of gelatine. It is presented with the fervent hope of creating an interest in the minds of a few readers, who will take the information and "run with it," exploring, refining, using and sharing the full potential of this medium within our craft.
GELATINE FORMULATIONS, COMPONENTS, AND MOLDING FOR PROSTHETICS
We recall from the first installment, that gelatine is obtained from protein collagen, which is widely found in nature, and is a major constituent of skin, bones and connective tissues. Because it is derived from a protein, it is essentially composed of amino acids. While this is a positive attribute for make-up artists (considering the frequently encountered and potentially dangerous chemical compounds found within the components of foam latex, urethanes, and similar industrial-rated prosthetic materials), it also identifies the inherent weakness of gelatine - it is "natural," and as such, susceptible to decay from the natural elements. This will become a key factor when we discuss gelatine formulations for molding prosthetics. But first, let me offer some terminology for working with gelatine.
In describing gelatine, manufacturers often refer to "bloom" strength. This is an industrial standard which "grades" or measures the strength of the gelatine. Essentially, it describes the relative "hardness" or "rigidity" of gelatine when cured. Higher "bloom" numbers correspond with stronger gelatines. Gelatine with a "bloom" of 300 can be obtained from most special effects suppliers, including Burman Industries, Inc. (www.Burmanfoam.com), The Monster Makers (www.Monstermakers.com), and others, and is considered to be the strongest for use in three-dimensional make-up effects. The Nabisco™ Food Service Company produces Knox(r) unflavored gelatine, which is readily available in the United States. An equivalent to Knox(r) in the United Kingdom is Davis(r) unflavored gelatine. Both brand names can be purchased from grocery stores, pharmacies or food service companies (in addition to its use as a nutritional supplement, it is also used in confectionery recipes - including those wonderfully molded gummy bears, fish and worms). Both Knox(r) and Davis(r) brand gelatines are believed to have a "bloom" strength between 200 and 225, and can be used during experimentation in three-dimensional gelatine effects.
Another term used to describe gelatine is "hygroscopic." Hygroscopic refers to the property of certain materials (like gelatine) to absorb moisture from the atmosphere. Hygroscopic is a necessary property for gelatine, because it allows the gelatine to become soluble (the capacity to liquify or dissolve). With the addition of water, as in most traditional (non-special effects) applications, gelatine particles begin to swell and actually absorb between five to ten times their weight in water. Because of the hygroscopic property of gelatine, traditional gelatine formulas for molded prosthetics and effects, swell in proportion to changes in humidity, and shrink with the onset of evaporation and time. This instability of gelatine formulas is another inherent weakness, and will become evident to anyone who uses a formula similar to the following:
1 package of Knox(r) unflavored gelatine granules to 2 tablespoons of very hot water.
(NOTE: A Knox(r) package of gelatine granules is equal to approximately two level teaspoons)
This formula works well in simple, quick, three-dimensional effects, but is not suited to our needs in using gelatine for molded prosthetics.
In addition to being artists, we must also become scientists, and base our experimentation in observation. If the addition of water is responsible for these changes, we must keep our "water to gelatine" ratios low, or eliminate water from the formula entirely. The goal is to have stability in the formula, without sacrificing flexibility or elongation of the gelatine molecules. Fortunately, we don't have to "reinvent the wheel" in this aspect. Make-up artists like Dick Smith, Kevin Haney, Frank Rogers, Matthew Mungle, and a host of others, have pioneered the way, and provided invaluable insight into the chemistry and nature of gelatine for use in three-dimensional make-up and prosthetics.
One of the solutions that grew out of early experimentation with gelatine for three-dimensional make-up, was to replace a percentage of the water content of traditional formulas with glycerin (glycerol). Glycerin, available in local pharmacies and grocery stores, is obtained from natural fats and oils, and is used in everything including cosmetics, inks, perfumes, certain glues, in automotive antifreeze, as a skin emollient and is used in the preservation and sweetening of food. In addition to its use in the make-up industry to produce "perspiration" and "grease" effects, glycerin entered into the basic gelatine formula, as in the following:
1 part gelatine, 2 parts water and 2 parts glycerin.
This formula resulted in gelatine with properties similar to many of the pre-packaged "gelatine effects kits" available on the market, but not specifically suitable for prosthetic work. With the addition of minute amounts of food coloring (red, blue or yellow), a multitude of injury effects could be created utilizing this formula - ranging from cuts and swellings, to bullet hits and burns - especially if the injury was created through the artful application of colored gelatine in layers (e.g., one red layer, one yellow layer, one clear layer, etc.). The gelatine could be mixed, colored, and stored in plastic squeeze bottles. When it came time to create the effect, the bottle could be placed in hot water (or while on set, in a hot cup of coffee), and allowed to liquefy. To assure that you didn't burn the actor, you always tested the temperature of the gelatine BEFORE application. The effect could then be sculpted directly on the actor, using a finger, brush, spatula, cotton swab or craft stick.
Interestingly, glycerin is also "hygroscopic." Kevin Haney, who has done considerable research for the use of gelatine in three-dimensional make-up, made a valuable observation* regarding this "hygroscopic" characteristic, during his use of gelatine burn appliances on the set of THE BELIEVERS. Kevin was working in rainy conditions, when one of the actors informed him that a nose appliance was loosening. When Kevin attempted to secure it, the appliance appeared larger than it should be. After successfully re-gluing the prosthetic, Kevin went back to his trailer to check his spare appliances and found that they were 10% larger when he compared them to the negative molds. His observation led him to believe that the appliances were swollen as a result of the high humidity. As a result, he began to replace some of the glycerin in his formulations with sorbitol, which is less affected by humidity changes, and is another component we should examine.
*(As submitted by Kevin Haney, published in Dick Smith's Advanced Professional Make-Up Course, Update #3, page 4. Kevin also notes that sorbitol makes gelatine firmer and less elastic. At the time of THE BELIEVERS, Kevin used a formula which included 7 grams of gelatine (275 to 300 bloom), 38 grams glycerin, 2 1/2 grams water, flocking, face powder and zinc oxide.)
Sorbitol is obtained from the breakdown of dextrose, and is used in the manufacturing of Vitamin-C supplements, candy, varnishes, synthetic resins, and as a sugar substitute for diabetics. While it occurs naturally in certain fruits, it may also be derived from corn syrup. Sorbitol increases the structural rigidity of gelatine formulas, thereby improving its tear resistance (an essential element for prosthetic work). There are two forms of sorbitol - liquid and powder. The inherent problem with the powder form is that you have to "tweek" the proportions of water to cause the sorbitol to dissolve into a solution - and water brings us back to "instability" in a prosthetic formula, with regard to changes in humidity. I have been successful with concentrations as high as 70% water to 30% sorbitol powder - with the expected drawback of appliance shrinkage over time (the process of evaporation). The liquid form of sorbitol usually contains higher concentrations of sorbitol to water, just enough to form the sorbitol solution. Liquid sorbitol can be obtained from Burman Industries, Inc., Michael Davy Film & TV Make-up (www.classichippie.com/davy/) and other suppliers (you may also be lucky enough to find it in your local grocery store or pharmacy). The powder form can be obtained through The Monster Makers. (Just a quick thought - you might also try mixing the sorbitol powder into glycerin to form a solution, eliminating water from the formula entirely).
One of the last formula components I would like to discuss is zinc oxide. To resist the breakdown of gelatine due to body heat and perspiration, make-up artists have found that the addition of zinc oxide to the formula actually results in a stronger gelatine prosthetic, with a greater tolerance to temperature changes. Zinc oxide is a water-insoluble powder (i.e., incapable of being dissolved in water), and may be available at a local pharmacy. However, the addition of zinc oxide will begin to effect the translucency of the gelatine in the final product - be careful of your proportions.
Because I was unsuccessful in locating powdered zinc oxide in a pharmacy, during my initial experimentation with gelatine, I utilized the next best thing... zinc oxide ointment. The particular brand of zinc oxide ointment that I used contained 20% zinc oxide, light mineral oil, white beeswax and white petrolatum. It produced very promising results. In fact, I have gelatine pieces in my studio that have survived the Florida heat and humidity for over six months now, without any sign of mold, mildew or rot (remember what I wrote at the beginning of this installment - gelatine is "natural," and as such, is susceptible to decay from the natural elements). The only change in the pieces is the development of a slight yellow tint, coupled with shrinkage (due, in part, to the 70% water to 30% sorbitol powder solution).
THE HANEY FORMULA FOR MOLDING PROSTHETICS
To produce those pieces, I used a variation on the following Kevin Haney* formula:
9 to 11 grams gelatine (275 to 300 bloom)
(Remember: the higher the "bloom," the greater the tear resistance)
21 grams sorbitol (70 %)
20 grams glycerin
up to 1/4 gram zinc oxide
*(As submitted by Kevin Haney, published in Dick Smith's Advanced Professional Make-Up Course, Update 3, page 5. NOTE: the components of colored flocking and colored face powder are not included in the referenced formula, as these topics will be addressed in the final installment to this series.)
A SIMPLE MOLDING PROCESS FOR GELATINE PROSTHETICS
PHOTOGRAPH 1 - ULTRACAL NOSE MOLD
Most make-up artists who "run" gelatine prosthetics, usually utilize (positive and negative) epoxical molds (Matthew Mungle), silicone or urethane (negative), or Ultracal (gypsum) molds. Because I run foam latex in Ultracal-30 molds (with Acryl 60 added), my initial experiments with gelatine appliances were conducted using Ultracal molds (positive and negative). For example, Photograph 1 illustrates an Ultracal-30 nose mold. The positive (left) is a "snap" relief from a life cast. The negative (right) is a mold of a sculpted (Roma Plastilina) nose. You will notice the "cutting edge" and "overflow" area on the negative, indicative of a mold made for foam latex work.
Although I have successfully run gelatine prosthetics without a separating agent, most sources recommend a microscopic layer of petroleum jelly on both mold surfaces. If you use vent holes in the mold, be sure to apply the petroleum jelly in these areas as well.
I heat the formula (provided above, with slight modifications) in the microwave, stirring occasionally to avoid uneven heating and literal cooking of the gelatine - if the formula gets too hot you may never be able to use it. You can also use a double-boiler to melt the formula. While I would love to give you a time for either technique, that will depend largely upon how many "batches" you are running, your components, and the power of the heat source (microwave or conventional cook top). So, I'll leave that to your observation. When the formula liquifies, and all of the components mix together, the formula is ready for pouring into the mold. When pouring, pour close to the mold to prevent splashing and the trapping of air bubbles.
CAUTION: THE FORMULA IS HOT AND WILL BURN!
FOR THIS REASON, IT IS RECOMMENDED THAT YOU WEAR LEATHER GLOVES AND EXERCISE EXTREME CAUTION!
After pouring the mixture into the Ultracal-30 negative, I carefully place the positive over the negative, and apply slow, constant pressure until the positive is seated firmly into the negative. Excess gelatine will overflow from the negative, and pool in the overflow area of the negative. Set the mold aside to cool (perhaps as long as thirty minutes to a few hours - depending upon the size of the mold). To decrease the cooling time, the mold can be placed in the freezer.
PHOTOGRAPH 2 - THE MOLDED PROSTHETIC
Photograph 2 depicts the cooled prosthetic, ready for demolding. Be careful when prying the mold apart that you do not tear the appliance or crack your mold. In Photograph 2, you may be able to see the prosthetic "flashing," which is just as fine as that produced by a foam latex appliance. To prevent the gelatine from adhering to itself, I powder the piece with corn starch baby powder (it's less expensive than neutral set powders). The overflow (or flash) of the piece should remain with the prosthetic until the time of application. The nice thing about gelatine is that it "forgives" - if you make a mistake during the molding process, or you don't like what you see - just re-melt the gelatine and try again.
PHOTOGRAPH 3 - A MOLDED AND DE-MOLDED (COLORED) GELATINE PROSTHETIC
The process of molding a gelatine prosthetic described in this installment, produces a strong, elastic, semi-translucent appliance, which is flexible, has inherently good resistance to perspiration and heat, and retains superb definition of detail from the mold. In fact, many artists who use gelatine remark that the retention of detail is another positive factor for using gelatine. Experiment for yourself and see the results first-hand.
In the final installment of this series, I will focus on the utilization of molded gelatine prosthetics, including adhesives, blending, sealing, intrinsic and extrinsic coloration, flocking, etc., and the future of gelatine in three-dimensional make-up.
CREDIT WHERE CREDIT IS DUE
Like many make-up artists of my generation, I stand on the shoulders of giants in the industry - those courageous souls who have pioneered the research, formulas and techniques of special make-up effects. I am eternally grateful to Dick Smith, who granted me permission to publish sections from The Advanced Professional Make-Up Course*, specifically for this article. All references are protected under international copyright laws. I am also thankful for the work of Kevin Haney, Frank Rogers, and Matthew Mungle, among many others - for their inspiration and generosity in sharing what they have learned with the rest of us.
*Smith, Dick. The Advanced Professional Make-Up Course. Connecticut: The Smith Family Trust, 1985-1996 (Including UPDATES).
THE FINAL INSTALLMENT OF
THE USE OF GELATINE FOR MOLDED PROSTHETICS
(c) 1998, Mitch Boudrot
All Rights Reserved