After Effects white background changes colour

[ugniusk55578824]

Hello all,

I am really new to AE and I'm learning the basics.

I have just created an online website AD and everything was good until I started to export. After exporting the background became black. I realised that I needed to add a SOLID layer of white at the bottom of my composition for it to act as a background which is fine however, I have a glow & hue & saturation effect above my background with accommodates to other layers above my background. So during the ad, my background starts changing colour.

How do I keep the background white? So its not affected by the glow & hue and saturation?

[Roei Tzoref]

How do I keep the background white? So its not affected by the glow & hue and saturation?

pre-compose all the layers but the background.

[Omar.Fathy]

There is another way to make a white background; when you make a new composition, you can change it's BG color:

But making solid layer is better for more cases.

In this case, You can make nested composition (or pre-composition) by making all your layers with effect but without the white Solid layer.

Then, Make new composition with the solid layer and drag the previous composition above the white one.
If you provide a screenshot for your layers, I can help you more.

[Rick Gerard]

Changing the background color of the composition will only give you a colored background in the final render if you render to a few specific formats. A composition always has an Alpha Channel with a value of 0, which is black. Black Alpha = transparent. Rendering to most formats will give you black everywhere there is transparency.

The only real reason to change the background color of a composition is to premultiply the comps background when you render a video with an alpha channel for further production. Sure, you can change the background color, and with some formats, it will show up, but adding a solid to the bottom layer does not increase render time, guarantees you will not have any render problems with any format and takes about 2 seconds, so unless you are an expert in video formats and compression and you know that your project will render properly, why bother changing the background color of a composition.