Finger Print photography when it comes to crime scene's is very important. It has been used to identify many criminals for more than 100 years. They also use it to connect murders between different crimes. some prints aren't visible but some may be. In order to collect the prints that aren't seen, the photographer needs to put a light dust on it and it will become visible or they use a vary vibrant light in order to see it. Once it is visible they put a metric ruler next to it in able to show how big it is.
The reason bloodstains are photographed is for the cops to connect type of murders and collect more evidence. Taking pictures of the crime scene can demonstrate all of the different patterns and untimitely determine how the murder happened.
The value of videotaping blood evidence is that the relationship that blood patterns and splatters can be demonstrated. With homicide videotapings can show how the bloodstains and patterns ar related. It can also connect them between several crimes. Photo documentation is always needed for the feds to be able to solve the crime. If someone tries to clean the blood stains all they have to do is get a high intensity light source and they'll be able to see the stains very clearly, then a picture is taken of it. Bloodstain pictures are taken up close. A good technique for recording a large area of blood spatter on a light colored wall is to measure and record the heights of some of the individual blood spatters. Yard sticks are used to see the actual size of the blood stains. Measurments and projections can then be used to determine where the splatters are coming from.