Luminosity Mask & Glows
After a little sharpening and noise reduction, we’re ready to Right-Click our image and select Edit In > Adobe Photoshop.
In Photoshop, go to your Channels Tab. Command (Mac) or Control (PC) click the RGB channel. This will create a Luminosity selection around your highlights. Now go back to your Layers tab and with your base layer selected, Cmd + J (Mac) or Ctrl + J (PC) to create a duplicate layer of your highlights. Call your new highlight layer “Glow.” This is where I also like to rename by bottom layer to “Base,” “Bottom,” “RAW,” or something like that. IMPORTANT: Turn off the visibility of your “Base” layer.
Next, with your Glow layer selected, go to Image > Apply Image. Make sure your Blending Mode is set to Multiply. Hit ‘Okay’ and now set your Glow layer’s Blend Mode to Screen and turn your Base layer’s visibility back on.
Go to Filter > Blur > Gaussian Blur. The radius will depend on how large your light source is, but I usually recommend somewhere between 5 and 20. Then set the Glow layer Opacity to 50%.
Finally, duplicate your Glow layer and rename it “Glow 2.” Apply another Gaussian Blur with a much larger radius, probably somewhere between 25-100. Now you can adjust the Opacity of your two Glow layers to adjust your Neon glow to to taste.