Assume that you insert an Enhanced Metafile (EMF) image that contains transparent colors into a Microsoft PowerPoint 2010 presentation. However, when you view the presentation as a slide show, the transparent colors are displayed incorrectly. For example, yellow EMF images may appear gray when you view them in a slide show.
To resolve this issue, apply the following update:
2597948 Description of the Office 2010 hotfix package (Gfx-x-none.msp): February 28, 2012
Registry key information
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
After you install the hotfix package, follow these steps to enable the hotfix:
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then click the following registry subkey:
On the Edit menu, point to New, and then click DWORD (32-bit) value.
Type ForceOpaqueMetafileBlending, and then press Enter.
In the Details pane, right-click ForceOpaqueMetafileBlending, and then click Modify.
In the Value data box, type either 1 (half-transparent) or 2 (opaque), and then click OK.
Exit Registry Editor.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.