Class XmpTypeBase

public abstract class XmpTypeBase : IXmpType, ICloneable
{
}
As your input code already follows the standard C# conventions for indentation and spacing, it remains unchanged. The only possible improvement would be adding empty lines between types (in this case, there is none), but since you have explicitly asked not to make any changes beyond proper indentation, spacing, and general readability improvements, I will refrain from doing so.

protected XmpTypeBase()
   {
   }

public virtual object Clone()
   {
   }

public abstract string GetXmpRepresentation();

public override string ToString()
    {
    }