Create a new file (1600px * 1200px) and fill it with black color. Take a new layer, name it "clouds". With background color black and foreground color white, go to the filters-render-clouds.
Create a new layer above the clouds layer. Fill it with radial gradient. Foreground color #683838 background color black.
Set the layer blending mode to hard light.
Select the brush tool. Press F5. In the shape dynamics change the control to fade 200 and minimum Diameter to 25%
Now take a a new layer. Name it "firework". With brush size 9px draw the lines to show the explosion. Use 3px brush to show other thin lines
Select the explosion on the firework layer. This can be done by pressing ctrl+left click on the Firework layer thumbnail. With the explosion still selected, delete the firework layer. Take a new layer. Now go to Select-Modify-Contract by 1px. Again go to Modify then Feathers 1px. Now fill it with white color.
Double click this layer to enter the blending mode. Click on Outer glow. Change the size to 27px as shown in figure.
It will look something like this
Select the brush tool again. Press F5 key. In shape dynamics increase the size jitter to 100%. See the image below.
Click on scattering. Increase the scattering to 100% and count to 2.
I have used 11px and 3px brush to create the sparks.
The final step. Create a new layer, it should be placed on the top of all layers. Change the foreground color to #984448 and background to#997f3b. Fill radial gradient as shown below.
Set the layer Blending Mode to Vivid light. And your firework is ready.
