How to Add Transparency to a Gradient in Photoshop CS6
By default in Photoshop CS6, a gradient has 100-percent opacity in the start color and progresses to 100-percent opacity in the end color. If you like, you can have the gradient fade out to transparency so that the portion of the image under the gradient shows through. To add transparency to a gradient, follow these steps:
Create a gradient.
Select the left opacity stop.
This stop is located just above the gradient bar.
Use the Opacity slider to specify the amount of transparency for the gradient at its start point.
You can also type a value into the Opacity box.
Select the right opacity stop, and then slide the Opacity slider or enter a percentage in the text box to specify transparency for the gradient at its end point.
The lower the percentage, the less opaque the color.
Move the opacity stops to the right or left to adjust the location where Photoshop applies each stop’s opacity setting.
Move the midpoint slider (a diamond icon) to adjust how the color and the transparency mix.
Click above the gradient bar to add more opacity stops if you want to vary the transparency of the gradient at different points.
For example, you could fade transparency from 100 percent to 50 percent and back to 100 percent to produce a particular effect.
Gradients ordinarily proceed smoothly from one color to another. If you want a less homogeneous appearance, adjust the Smoothness slider to a value of less than 100 percent (click the right arrow to access the slider).