Embedded Files
Luminance
Luminance
As usual, I've loaded the luminance, RGB, and star masters into Photoshop and placed them in separate layer groups, with global adjustments in between.
The lum group gives us our detail and brightness. We can enhance the data by large-scale sharpening, darkening the bright nebula core, and lightening the dark clouds.
The Iris core is bright, which will wash out color later on. We'll use a paintbrush, in soft light blending mode, to darken (or burn) the details. Use black and a very low opacity (5%).
Details of the Lum group.
Unsharp Mask can be an effective way to enhance both large-scale contrast and small details. Here, we're using a large radius to make large nebula structures stand out.
Before burning.
After burning.
Before adding a levels adjustment layer.
After brightening with levels.
Color
Color
The RGB layer will get similar treatment: some burning and a levels adjustment, with the addition of increased saturation.
We'll also apply a filter to the base color layer. HLVG, or "Hasta La Vista Green", is an old astrophotography filter for removing green color casts, useful since green is rarely seen in space. It also works well with images from one-shot color cameras, which often exhibit a strong green bias due to their filter matrix.
The color layer with a bit of green removed.
When the color layer group is set to "color" blending mode it will take its brightness from the luminance group.
Darkening the colors can enhance the richness and saturation of the resulting combination.
Lum and color combined. What a difference!
Global Adjustments
Global Adjustments
This group of adjustment layers will affect both the color and brightness. Very little adjustment is necessary.
Let's add some contrast with Curves, along with some minor adjustments to the saturation of the reds, cyans, and blues. The Color Dodge layer provides additional contrast and a slight increase in brightness, while the Lighten layer brightens any extremely dark pixels. This results in a nicer, more natural-looking background.
Only a light curves adjustment.
A solid fill layer is exactly what it sounds like. RGB values of 19, 19, 19 will work well. Setting this layer in Color Dodge blending mode adds pop.
Finally, we'll copy this layer and set it to "Lighten" blending mode. This will raise the value of any pixels below it that are darker than the fill color. In this case, it will raise any pixels below 19 to a value of 19. It's a subtle change, but an important one.
Before.
After global adjustments.
Stars
Stars
The star layer gets the standard treatment. A minimum filter (at 0.4) eliminates some of the tiny, distracting stars, and a levels layer shrinks them further with a mid-tones adjustment. Finally, increasing the saturation restores some of the color that is lost when we put the group in "Screen" blending mode.
The Result
The Result
A single luminance image.
15 hours of data combined and processed.
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