User Guide - Film Halation
Make images look like film with halation
Film Halation adds realistic film-like glow to the highlights of your images. You can control the brightness threshold at which halation occurs. The halation algorithm in the color.io app improves the glow core with exponential light falloff and color gradation to very accurately simulate real film halation for your photos. Adjust strength, radius and threshold with the sliders in the UI and fine tune saturation and hue of the halation for even more control.
You can find the Halation effect in the Material Panel at the bottom of the Color Grading Section in Color.io.
Understanding halation
Have you ever noticed a warm, red-orange halo around overexposed areas or contrasting boundaries in film photographs? That glow is called halation, a visual phenomenon that's unique to film photography. With Color.io, you can apply this effect to your digital images to make them look and feel like true analog film. Let's delve into how halation occurs.
The physics of halation
Think of film as having three layers: Blue, Green and Red. The layer closest to the light source is the blue layer, the middle is the green, and the left layer is the red. Now, when you take a picture, light moves through these layers from blue to red. Without something to stop the light, like an anti-halation layer, the light goes all the way through and hits the back of the camera. When this happens, the light bounces back and hits the film layers again, but this time in the reverse direction. The red layer is hit by the reflected light first. This reflection creates the distinct red glowing effect or 'halation'.
When the light is super bright the reflection can be even stronger and reach even further back through the emulsion, penetrating the 'green' layer too. When this happens, the halation effect takes on an orange tint. Why? Because mixing red and green light gives us yellow light, and the yellow mixed with the red halation we started with gives us orange.
Simulate halation in digital photos
So how can you replicate this charming, vintage effect in your digital images with Color.io? Color.io is a web based photo editor and film emulation tool that has settings that closely align with the physical phenomena that produce halation. It provides controls for managing the intensity, radius, hue, saturation and threshold, giving you control over the brightness level at which halation occurs. Color.io recognizes that while halation spreads freely within the emulsion, red-orange halos are typically discernible only against darker backgrounds and automatically emulates this behaviour. By providing users with this understanding and the means to adjust individual parameters, Color.io enables digital photographers to closely mimic the aesthetic properties of film.
With Color.io you can edit images and build 3D LUTs with a powerful online raw developer and analog film look designer for photographers and filmmakers. Craft stunning film color in record time that works for any camera, in any software and on any device, directly in your browser.
