private void createLeftQuad() {
        Material material = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");

        // This color creates a blue value image. The effect will have a strength of 80% (set by the alpha value).
        material.setColor("Color", new ColorRGBA(0f, 0f, 1f, 0.8f));

        // Result.RGB = Source.A * Source.RGB - Source.A * Destination.RGB
        // Result.A   = Destination.A
        material.getAdditionalRenderState().setBlendMode(RenderState.BlendMode.Custom);
        material.getAdditionalRenderState().setBlendEquation(RenderState.BlendEquation.Subtract);
        material.getAdditionalRenderState().setBlendEquationAlpha(RenderState.BlendEquationAlpha.Add);
        material.getAdditionalRenderState().setCustomBlendFactors(
                RenderState.BlendFunc.Src_Alpha, RenderState.BlendFunc.Src_Alpha,
                RenderState.BlendFunc.Zero, RenderState.BlendFunc.One);

        leftQuad = new Geometry("LeftQuad", new Quad(1f, 1f));
        leftQuad.setMaterial(material);
        leftQuad.setQueueBucket(RenderQueue.Bucket.Transparent);
        rootNode.attachChild(leftQuad);
    }
Adds a "transparent" quad to the scene, that shows an inverse blue value sight of the scene behind.
jme3-examples/src/main/java/jme3test/renderer/TestBlendEquations.java