LED Photography Light: Adjustable Colour Temperature

A good LED photography light can transform your photos and videos, and building one yourself saves 60-80% over commercial panels. By combining warm white and cool white LED strips with a PWM controller, you get adjustable colour temperature from 2700K to 6500K — covering every photography scenario from warm portraits to crisp product shots.

Why LED Panels for Photography

• Adjustable colour temperature: Match any ambient light or creative mood
• High CRI (90+): Accurate skin tones and product colours
• Dimmable: From subtle fill light to full brightness
• Portable: Battery-powered for location shoots
• Cost: Rs.500-1500 DIY vs Rs.3000-10000 commercial

Understanding CRI and Colour Temperature

Two critical specifications:

• CRI (Colour Rendering Index): Measures how accurately colours appear. CRI 90+ is essential for photography. CRI 95+ is professional grade.
• Colour Temperature: 2700K (warm, like sunset) to 6500K (cool, like overcast sky). 5500K is standard daylight.

Always check the LED strip CRI rating — cheap strips are CRI 70-80, which makes skin look grey and colours look muddy.

Dual-Colour LED Design

Mount two strips side by side on an aluminium panel:

• Warm white (2700-3000K): Warm, flattering light for portraits
• Cool white (6000-6500K): Clean, bright light for products and outdoor matching

By varying the brightness ratio of each strip, you smoothly adjust the combined colour temperature anywhere between 2700K and 6500K.

PWM Mixing Controller

#define WARM_PIN 5
#define COOL_PIN 6
int totalBrightness = 200; // 0-255
float mixRatio = 0.5; // 0=all warm, 1=all cool

void setColourTemp(float ratio) {
  int warm = totalBrightness * (1.0 - ratio);
  int cool = totalBrightness * ratio;
  analogWrite(WARM_PIN, warm);
  analogWrite(COOL_PIN, cool);
}
// ratio=0.0 -> 2700K, ratio=0.5 -> ~4500K, ratio=1.0 -> 6500K

Use two potentiometers: one for overall brightness, one for colour temperature mixing.

Diffusion and Light Quality

• Bare LEDs create harsh, point-source lighting with sharp shadows
• Add a diffusion layer: tracing paper, frosted acrylic, or professional Lee diffusion gel
• Increase diffuser distance from LEDs for softer light
• A larger diffuser area creates softer light — the key principle of photography lighting

Battery-Powered Portable Panel

• Use 3S 18650 battery pack (11.1V) with a step-down converter to 12V
• At 20W total LED power, a 3000 mAh pack provides 1.5-2 hours of runtime
• Add a voltage display module (Rs.50) to monitor battery level
• USB-C charging with TP4056-based 3S BMS for convenience

Mounting Options for Video and Photo

• 1/4-inch thread mount on the back for standard tripod/light stand compatibility
• Cold shoe mount for camera hotshoe attachment
• Barn doors (3D-printed) for light direction control
• Magnetic mount option for flexible placement

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