How to Add God Rays to an Indoor Portrait in Photoshop

Add a single shaft of light to an indoor portrait and the mood changes immediately. The method: select the highlights, pull the beams out with Radial Blur, switch the blending mode to Screen, then fine-tune the strength and direction. Free Online PS handles all of it — no install required.

Step 1 Open the image and duplicate the layer

1️⃣ Open Online PS in your browser → File → Open and pick your indoor portrait.

2️⃣ In the Layers panel on the right, select the Background layer and press Ctrl + J (or right-click → Duplicate Layer) to create a copy, then name it Highlighter.

Tip: leave the original layer untouched. Every edit from here on happens on the copy, so you can always roll back.

Step 2 Select the highlight (light source) area

Press Ctrl + Alt + 2 (in Photoshop this maps to Select → Color Range) to open the Color Range dialog.

• Place the sampler eyedropper on the brightest highlight — the subject's face or the window.

• Set Fuzziness (⌀) to 30–45 so the bright areas are selected in full. (If that feels unfamiliar, use the Magic Wand W and click the highlight manually with Contiguous turned off.)

Step 3 Fill with white

With the selection active, choose Edit → Fill (Shift+F5).

In the Fill dialog:

Set Contents to White (or just type #FFFFFF)
Leave Mode at Normal
Set Opacity to 100%

Confirm, and the whole selection turns solid white — the raw shape of the light patch.

Step 4 Duplicate the white layer

Select the layer you just filled with white and press Ctrl + J once more to get the Light‑Blur layer.

Step 5 Radial Blur (to simulate the light)

Select the Light‑Blur layer → Filter → Blur → Radial Blur (Ctrl + Shift + F).

In the Radial Blur dialog:

Set Amount to 100 (adjust to your resolution)
Choose Zoom as the blur method
Drag the center crosshair to the top-right corner (toward the window that provides the light)
Keep Blur Quality at Best

Confirm, and the white patch stretches into rays radiating toward the upper right — the beginnings of the god ray effect.

Step 6 Position the light and boost it (if needed)

Use the Move tool (V) to drag the Light‑Blur layer to where the light actually appears (usually behind the subject or near the window).

If the rays look too weak:

Press Ctrl + J again to duplicate Light‑Blur; stacking the copies makes the light brighter.
Or set the layer's blending mode to Overlay or Screen and drop Opacity to 70%–90%.

Step 7 Merge and fine-tune the whole image

Select every light-related layer (Shift+click), right-click → Merge Layers (Ctrl + E) to produce a single God‑Ray layer.

Final tweaks:

Levels (Ctrl+L) — adjust the white and black points so the light looks more natural.
Hue/Saturation (Ctrl+U) — add a little warmth or coolness to the light (for example, raise Saturation by 10% and shift Hue 5° toward yellow) so it matches the scene.
The Soft Light blending mode is also commonly used to give the rays a hazier feel.

References

Adobe Photoshop official documentation
HTML5 and the principles of modern front-end image processing
Online PS