The following tip works in Photoshop CS3 & CS4.

If you have ever merged multiple layers (Layer > Merge Layers) that have different blend modes you may have noticed that the blend mode effects are not maintained and the merged version looks different than the un-merged version.

Try this method instead:

  1. Make sure that the layers you want to merge are the only ones visible.
  2. Create a new blank layer and select it.
  3. Use this keyboard shortcut: Ctrl + Shift + Alt + E. This merges all visible layers onto the selected layer.
  4. That’s it! You can now delete the layers that were merged and all of the blend mode effects should be maintained.