All of the layers we've worked in AE so far consist of materials we have imported from other sources - video, graphics, etc. However, you will often find the need for a simple, blank layer - especially when using effects that essentially replace the contents of a layer with the effect itself(i.e. many of the effects in the 'render' submenu). Solids fulfill this role - they are a simple layer, with all the same properties of any other layer, with no content other than the color you choose.
Solids are easy to create using any of the following methods:
- From the main menu choose Layer>New>Solid.
- Control-click(right click on a two-button mouse) on any empty area of your timeline and from the contextual menu that pops up choose 'new>solid'.
- Use the keyboard shortcut Apple-Y.
Regardless of which method you choose you will be presented with the Solid Footage Settings dialogue:
This gives you several options for your solid. The first is the name - you can give it a name if you wish but if you leave this field alone it will automatically name the solid based on the color you choose later (1). Below this you can set the width and height for your solid - this value will default to whatever you used the last time you created a solid (2). The button below will automatically set the width and height values to the current size of your composition (3). Finally, in the lower half of this dialogue you have a color swatch and eyedropper for choosing the color of your solid (4). If you click on the color swatch it will bring up a standard RGB color picker; use the eyedropper to sample a color from somewhere else on your screen (a graphic in your composition, for example). Click 'OK' to apply these settings and create the new solid.
Once you've created the solid it will appear in two places - as a new layer in your current composition and in a folder in your project window named 'Solids'. This allows you to re-use the same solid anywhere in your project without having to create a new one.
You can also change a solid's settings after you have created it - select the solid in your timeline or project window and from the main menu choose 'Layer>Solid Settings' to bring the settings window back (or use the keyboard shortcut Apple-Shift-Y). If you change the color of the solid this way it's name will change to reflect the new color,.
You can manipulate the solid in your composition just like you would any other layer - change it's transform properties, keyframe it to create animation, apply effects, etc. If you need areas of solid color with shapes other than square or rectangular you can apply one or more masks to the solid (see my animated masks
notes for more on masking).
Solids can also be useful for creating solid color backgrounds or fades/flashes to colors. For instance, if you have a dozen layers on screen and you want to have them all fade to black, you could just keyframe the opacity for each layer so that it fades away in sync with all of the other layers...but that's a lot of work. Instead, create a solid black layer and place it above all the other layers on your timeline, then keyframe it's opacity slowly from 0% to 100% until it obscures all of the other layers. Use a white layer instead and make the fade much faster to create a bright flash that obscures everything.
As you can see, creating and using solids is very simple, but you will find you use them more and more as you work with AE.