Ruler placement for latent prints on curved objects

[DanielleO6283]

Good morning all,

Lately there has been some question on where to appropriately place a ruler to photograph a latent on evidence. Some people put the ruler on the object right next to the latent curving it if its a curved object or flat. Others believe that the ruler needs to be propped next to the object and be flat in order to get the best calibration of the latent. My question is what is the consensus do we put the rulers on the evidence which makes it on the same plane to get the most accurate result for the databases as well as sizing of the latent itself or is ruler propped next to item sufficient enough? Thanks in advance!

-Dani

[timbo]

Dani -

I would submit that for accurate scaling, it is most important to put the scale down flat on the same plane as the majority of the latent. I would place an adhesive scale lightly on the curved item as close to the latent without interfering with ridge detail and on the same plane as the latent, but not sticking the scale down around the curve. Alternatively (if you don't want to use an adhesive scale), you could somehow prop a ruler to do the same, but this would be more difficult.

The only other consideration is then placement of your light source, so that you don't get shadowing from the scale.

My two cents.....

[ER]

It really doesn't matter.

[areitnau]

My opinion would be to place the ruler on the item along the curved length of the latent impression. In order to best maximize the potential for a fruitful search, the 1:1 calibration would be most accurate along the entire latent if the measurement followed suit. While it may not make much of a difference, I would imagine that a scale placed next to the impression would lead to an increased search yield due to a correct measurement/calibration.