string sourceFileName = "WithoutVibrance.psd";
string outputFileNamePsd = "out_VibranceLayer.psd";
string outputFileNamePng = "out_VibranceLayer.png";

using (PsdImage image = (PsdImage) Image.Load(sourceFileName))
{
    // Creating a new VibranceLayer
    VibranceLayer vibranceLayer = image.AddVibranceAdjustmentLayer();
    vibranceLayer.Vibrance = 50;
    vibranceLayer.Saturation = 100;

    image.Save(outputFileNamePsd);
    image.Save(outputFileNamePng, new PngOptions());
}

string sourceFileName = "VibranceResource.psd";
string outputFileName = "out_VibranceResource.psd";

using (PsdImage image = (PsdImage)Image.Load(sourceFileName))
{
    foreach (var layer in image.Layers)
    {
        foreach (var resource in layer.Resources)
        {
            if (resource is VibAResource)
            {
                var vibranceResource = (VibAResource)resource;

                int vibranceValue =  vibranceResource.Vibrance;
                int saturationValue = vibranceResource.Saturation;

                vibranceResource.Vibrance = vibranceValue * 2;
                vibranceResource.Saturation = saturationValue * 2;

                break;
            }
        }
    }

    image.Save(outputFileName);
}