Blurring the edges of a layer on Gimp?

Question

I am trying to blur a layer on a Gimp photo. It's a pink layer called 'Capa 1'. I have tried inverting the layer, and feathering however it hasn't worked.

I need to blur the edges so they are not sharp on the website I need it for: https://takanodan.net

This is the file: https://www.dropbox.com/s/hl07vppnvdf50hs/headerimage.xcf?dl=0

Anyone help me and guide me through? Can't figure it out.

Thanks!

Answer 1

Simple way

1. Layer>Transparency>Add alpha channel (if grayed the alpha channel is already there)
2. Layer>Transparency>Alpha to selection
3. Select>Shrink by N/2 pixels (N being the span of the feathering)
4. Select>Feather by N pixels
5. Select>Invert
6. Edit>Clear or [delete]

For more precise control

7. Layer>Mask>Add layer mask and initialize to Transfer layer's alpha channel. The mask will have a white center and a black border, with a gray area between the two. Further operations apply to the mask (click on the layer preview if you layer need to work on the layer itself)
8. Select>None to remove the selection
9. Use Curves, Levels, or Brightness/contrast to play with the gray area
10. You can use Layer>Mask>Apply mask when done (but you can also keep the mask as is)

Answer 2

Use a gaussian blur filter on the layer, set the radius around 45px. This will blur out the right and left edges.

Then select the Eraser tool, and in the Tool Options lower the brush Hardness, and increase the Size to get a large soft edged brush.

Erase along the top and bottom edges.

Here's the result.

Answer 3

It sounds like you are trying to create a gradient to another color or opacity.

1. In the Layers box, right-click the layer, and then click Add Layer Mask.

2. Select the appropriate transparency setting, and then click OK.

3. Using the Blend Tool L, create the gradient.

4. Right click the layer, and then click Apply Layer Mask.