Translucence In Nature and Fly-Tying
Kurt Shaffer- PGH Fly Co
Translucence is one of the most common things in nature, yet it's an often underutilized visual trigger in fly design. In nature, many of the organisms trout feed on—fish eggs, larvae, worms, and certain baitfish—are not opaque. Light penetrates the body, interacts with internal structure, and exits differently depending on angle, depth, and movement. This creates contrast and subtle flash that can trigger a strike in stubborn fish.
When you begin designing flies with translucence in mind, material selection and application become far more important than color alone. The fly-tying world is full of materials that produce translucence when applied in thin layers. My favorite material for this effect is McFly Foam. It's especially effective because it diffuses light rather than blocking it. Thickness control is critical—too thick, and the material becomes too solid; therefore, it must be thin enough to allow internal components to remain visible once the fly is wet. McFly Foam has become my primary material for worm bodies and egg patterns, primarily because of this reason. A good example of this approach is the development of the Husky pattern. During periods when Walnut Husk Fly Larvae are present, translucence is a defining characteristic. As the larvae feed on decomposing husk material, their digestive tract is often visible through the body wall. Replicating this meant building the fly from the inside out. The body begins with a thin, reverse-tied layer of foam. Underneath that, tinsel and thread are used to suggest internal mass rather than surface flash. This internal layering creates depth without overpowering the profile. Once the foam is pushed forward and wetted, it puffs up and clarifies, allowing the internal materials to show through in a way that nearly matches the natural. The result is a fly that maintains realism under varying light conditions rather than looking like a solid object.
The same internal-structure approach is used in the NKC Egg. While McFly Foam egg patterns have existed for years, most rely on surface color placement. For the NKC Egg, the goal was to create a "fertilized egg" pattern that was just more than a mix of McFly Foam colors. I wanted it to have depth, to see inside the shell. This was achieved using a layered tinsel core, which has been used externally on many of PGH FLY CO patterns. On its own, the tinsel is extremely bright, but when filtered through a semi-transparent foam shell, the light is diffused rather than reflected directly, which gives it a completely different effect. As the egg moves in the current or reacts to turbulence, the loose foam shell will move slightly and allow the tinsel to shimmer internally, producing a three-dimensional effect instead of a static flash.
The NKC Blood Dot follows the same logic. The entire goal was to have the illusion of a substance being contained in a shell. Rather than placing a red hotspot on the exterior of the egg or just using a strand of red foam, a small amount of very fine, stringy red flash dubbing is buried at the center of the pattern. Once covered with foam and wetted, the dubbing spreads out and creates a suspended blood effect that appears internal rather than painted on. The metallic flash of the red dubbing is almost fully absorbed, creating an amazing, realistic blood color and texture. What was once bright becomes surprisingly subtle. This subtlety becomes especially important in clear water or pressured fish.
Translucence also plays a role in streamer design, particularly in the Liquid KO variations. The fly uses contrasting materials to control how light interacts with the pattern. The inner section of the fly is a wrapped holographic tinsel. The bottom of the fly is built with a stiff and dense craft fur, which holds shape and limits light penetration. The top uses white Polysilk, which is significantly softer and more translucent. This material contrast creates two distinct behaviors. While free-floating or dead-drifting, the Polysilk absorbs and diffuses much of the tinsel's shine, keeping the fly subdued. Once the fly is moved or disturbed by water current, the Polysilk will move, allowing the tinsel to flash aggressively. This on-off flash effect closely mimics the way real baitfish reflect light when they change direction.
From a design standpoint, translucence isn't about making flies brighter—it's about controlling light. By allowing light to pass through a pattern, interact with internal materials, and change with movement, you add depth, realism, and trigger points that most flies simply can't replicate. When flies are built from the inside out, they start looking like food!
