Add a blissful glow to the highlights of a photo.  This effect works well with portraits.
Bloom Photoshop Tutorial
Preparing the Document

Step 1
Open an image to edit.
Photoshop bloom Effects
Step 2
Duplicate the layer (Layer> Duplicate Layer or Ctrl+J) and change the blending mode of the new layer to Screen.
Photoshop bloom Effects
1.    Add a layer mask to the top layer (Layer> Layer Mask> Reveal All). Make sure that the layer mask is selected.
Photoshop bloom Effects
Creating the Mask
In this section, we’ll be editing the layer mask to mask out the effect from the shadows.
Step 3
Use the Apply Image tool to apply the Background layer to the layer mask. To do this, open the Apply Image tool (Image> Apply Image) and change the Layer to Background and click OK.
Photoshop bloom EffectsStep 4
Hold the Alt key and click on the thumbnail of the layer mask.
Photoshop bloom Effects
Step 5
With the layer mask still activated, use the Threshold tool (Image> Adjustments> Threshold) and adjust the slider to define where the bloom Photoshop effect will be visible.
Photoshop bloom Effects
Adjusting the Effect
We’re now ready to edit the effect. This section is where we’ll see the bloom effect in action.
Step 6
Click on the thumbnail of the layer (not its layer mask) to deactivate the layer mask.
Photoshop bloom Effects
Step 7
Open the Gaussian Blur filter (Filter> Blur> Gaussian Blur). Ensure that Preview is enabled and increase the radius to achieve your desired effect.  Photoshop bloom Effects