AMPt Darkroom:
Enhancing Ambient Light and Contrast Using the Luminosity Blend Mode

Device/Platform: iPhone, iPad / iOS
Featured Apps: Noir, Filterstorm, Image Blender
Topics Covered: Layers, Blending Modes, Tuning, Contrast

Intro
If you’re looking to take your editing to the next level you’ve probably started to explore layers, masking and blend modes. While you don’t need to know everything about blend modes to benefit from their use, having a solid understanding of them can expand your editing arsenal considerably and give you more precision and control over your final image.

Lesson Focus
In this Darkroom lesson I’ll be focusing on a technique that utilizes the Luminosity blend mode to enhance the dynamic light and contrast in an image. While there’s no right or wrong time to use this technique, you’ll notice it’s especially effective when used to enhance images that feel flat, lack depth or dramatic ambiance. I’ll focus on one example in this lesson but keep in mind that this technique can be applied (with varying degrees of impact) to almost any photo.

Background
Now before I walk you through the step-by-step I want to quickly touch on what the Luminosity blend mode actually does. Don’t care for the technical details? Skip to the next paragraph to jump right into the step-by-step. Still with me? Cool. So Luminosity is in the “Composite” group of blend modes along with Color, Hue and Saturation and is the exact opposite of the Color blend mode. While the Color mode blends the color values of the two images and ignores the lightness values, Luminosity mode blends the lightness values and completely ignores the original color values. In other words, if you blend two images using Luminosity mode, the color won’t change at all but the brightness and contrast values will. This is the fundamental point that makes Luminosity blend mode ideal for the technique shown below.

Technique
In this example, I’ve selected a shot of some trees (feel free to save this image to your device and use it when following along with this lesson). Notice that the shot feels busy, repetitious, lacks depth and a general focal point. This is a great candidate for this technique.

Start by opening the image in Noir and select the first preset (far left) to position the reticle over the entire image. Now dial the contrast (far right dial) down to between 5-10. Essentially, we’re trying to remove as much of the original contrast from the image as possible so we have a somewhat flat gray image to work with. You can dial UP the outer brightness (far left dial) or dial DOWN the inner brightness (middle dial) as you see necessary from here but I’ll be leaving it as is. Now Save this image and immediately reload the saved image back into Noir.

With the flat gray image loaded back into Noir hit the second preset (blue spotlight) and switch from the blue tone back to black and white again. The default contrast of 65 (right dial) can be a little intense for some shots so I’ve dropped it down to around 30. Save this shot and we’re ready to start blending.

Now the blending can be done using almost any app that has the Luminosity blend mode but I’ll be focusing on blending using Filterstorm and Image Blender.

Filterstorm:
- First, load the original color image in Filterstorm
- Tap Filters > Add Exposure and select the final b&w image created in Noir
- Change the blend mode to Luminosity and tap the “Fit to Image” button
- Once loaded tap the Opacity mask option (circle split in half vertically)
- Adjust the Opacity slider to your liking (I used 75% below), Apply and Save

Image Blender:
- Load the original color image in the left image holder
- Load the black and white image in the right image holder
- Tap the Blend button and change to Luminosity
- Adjust the Opacity slider to your liking (70-75% again) and Save

If after blending you find that the contrast/spotlight is a little off you can just open Noir from your multi-task bar and move/adjust the reticle or contrast, save and re-blend again.

Final Image
Here is the blended image saved out of Filterstorm. You’ll immediately notice that the final edit is much easier on the eyes than the original shot. We’ve created more of a focal point within the image, reduced the repetitious and busy feel and enhanced the lighting to bring out a warmer and more dream-like ambiance.

- Adam Conner @derblutenkat

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