Chart Gradient Backgrounds Appear Gray in Internet Explorer
In IBM®
Cognos® Analytics - Reporting, you can define a custom palette for a chart that includes a gradient. When the chart is rendered in HTML format in Microsoft Internet Explorer, the chart background appears gray. This is an Internet Explorer issue.
To avoid this problem, select the chart and define the color white as the chart background.
For more information, see the Microsoft Knowledge Base article # 294714 at http://support.microsoft.com.