I assume the letters are supposed to be transparent? Could be the color in World Properties, if there’s nothing behind the picture then the ambient color will be rendered. Set it to full white or set strength to 0 if you want no ambient color.
Edit: you may also need to set Render Properties > Film > Transparent if you need it rendered as empty where the gray letters are.
If it doesn’t work you should provide more details about what you’re trying to do.
The letters should be pure white, while the background is transparent.
I have set film to transparent and I have set color management to standard.
When I hit render, the image appears “WHITE”, then when I save the image as RGBA and view it, it appears gray. However, the same image from the render result window appears all WHITE when saved as RGB.
Here is the same image from the render result window, just saved as RGB. Notice how the letters and logo are pure white… but as soon as I hit save as RGBA, it turns gray