Dude did you read where i described what i meant by blending? Superimposition of course is used when there are similarities to further drive those similarities home. It doesn't lend itself to noticing the differences. Science seeks to eliminate possibilities to find results not seek things that match. This is why things like bite mark forensics can be so easily attacked In court. And even as good as fingerprint evidence can lead to someone like attorney Brandon Mayfield in Washington being falsely identified as being suspected of terrorism across the world because his fingerprint “matched” the actual terrorist. Sorry bud its just not a good way to determine two people are related absent other evidence