The FX tool includes gradients tools, a warping tool, novas and lens flares, an alpha fading tool, and a lightning tool. Clicking on the icon holds a few surprises. You can also select all its options from the context bar that appears at the top.

Here are examples of the linear and circular gradient tools.

These tools have a number of uses.  For example, you can use a linear gradient to make a sky, or you can use a circular gradient to make a 3d shape by using a spherical alpha selection.

These tools will use whatever gradient is set in the fill/gradient panel, and you can edit your own if you want.

To select a gradient, just drop down the gradient selector from the context strip for any tool that supports filling, such as the floodfill tool, the rectangle and ellipse tools, and the curve tool.

Combine modes can be used with gradients to create unique effects like the one to the left.  Select them from the Gradient modes sub menu.

This effect was created with the linear gradient tool, and the 'greater than' combine mode.

The Linear Alpha Fader tool is one of the most useful tools in Howler for a number of different uses.

It will fade out part of the alpha channel, making it possible to apply neat gradient effects to the alpha.

Here, you see the Linear Alpha Fader as it has been applied to a blank alpha channel.

Here, you can see how it is used with another tool, in this case, the color adjustment filter.

And you can see how it can be used with images (selections) already in the alpha channel.

Warping lets you create a bulge or pitted area in an image.  The best way to make use of this is to experiment, as the effects can be very interesting and fun to manipulate.

Novas are similar to lens flares.  They are effects like you might see from an intense pinpoint light entering a camera lens.

Novas are always additive, and they use the current primary color.  You won't see anything if you work on a white image, or use black as your primary color.

You can add multiple novas of different colors to get more interesting effects.

Novas are always additive and use the primary painting color!

Lens flares

Lens f;ares are effects created by an intense light shining into a camera's lens assembly.  The light reflects from lens to lens, creating a sometimes beautiful effect.

While lens flares are undesirable in photography, they are used quite often in special effects simply because they look neat, and they help simulate the way footage from an actual camera would look.

Many dramatic lighting effects are possible with lens flares.

It is possible to edit every parameter of a lens flare, including the size, shape, and color of each lens reflection (The shapes that are actually a reflection of a cameras shutter, reflected within the cameras lenses. It is possible to simulate many types of cameras, or many types of dramatic lighting effects as well.

By applying a gradient to a lens element, it is possible to even create a rainbow, as seen to the left.

Because it can be tedious to setup a lot of indevidual elements, there are a number of tools to help automate the process.

PD Pro has a lightning utility built in.  It can be used to create electrical storms or special effects.  The effect is additive, and always set to a blue shade.  You can use a layer, and additional tools if you desire to change the color.