Photography
FLUORESCENCE
When utilizing a fluorescent chemical or dye stain on scene or in the processing laboratory, photographs can be used to document any reactions that are observed and/or any evidence that develops such as latent prints.
Documenting Bloodstains
These bloodstain reagents are most often used for searching for stains that are not readily visible. When using these bloodstain reagents, finish steps 3, 4 and 5 and have the camera fully set up and ready to photograph before the application of the reagent:
These bloodstain reagents are most often used for enhancing minute details like those present in latent print and shoe impressions. When using these bloodstain reagents, the camera can be set up before or after the application of the reagent:
Choose the appropriate lens and camera settings for the area that you are photographing. You will likely be transitioning to your manual camera settings for these photographs.
Some fluorescent/luminescent bloodstain enhancement reagents will be visualized best in the dark. That being the case, you will want your camera to collect as much light information as possible by setting the shutter speed so that the shutter is opened for a prolonged period of time.
For these photographs, you will want to use a tripod. The tripod will give the camera stability, while hand holding the camera can lead to blurry images.
If the reagent you are using is for the purpose of searching for bloodstains, set the tripod up so that the camera lens is pointed toward the area that you want to photograph.
If the reagent you are using is for the purpose of developing bloodstains for possible future analysis/comparison, set the tripod up so that the camera lens is perpendicular to the item you want to photograph. Before taking photographs, you will want to check that your camera is truly perpendicular using a bubble level. Set the bubble level on the camera and adjust as necessary until the camera is perfectly perpendicular to the item being photographed.
If the enhancement reagent requires you to wear a certain type of barrier filter googles to see it, then the camera needs the same barrier filter to see it as well. Choose the appropriate filter for the reagent you have chosen and attach it to the camera lens.
If the reagent you choose requires a light source to visualize it, you will want to have your light source ready to go.
All one-to-one photographs should include a scale. The scale should be placed next to the item being photographed on the same plane as that item.
If the reagent chosen is a searching reagent, document the results of the application of the bloodstain enhancement reagent to the entire area immediately with digital photographs since the initial reaction tends to fade over time.
If the reagent chosen enhances minute details, fill the entire frame of the photograph with the item you are wanting to capture. The scale should be visible at the edge of the photograph. Take multiple photographs of the item, moving the light source around to capture as much detail as possible.
Before moving on, check the photographs you have taken to ensure you captured what was needed. If you did not, go back and photograph again while you have the chance to. Bloodstain enhancement chemicals that are used for searching can typically be reapplied if photographs did not capture the results the first time. Be careful, however, not to oversaturate the area and dilute the stains.
Documenting Latent Prints
Apply dye stain of choice to the surface. For more information on which dye stain to use, refer to this resource: Processing Surfaces.
Choose the appropriate lens and camera settings for what you are photographing. You may need to change to a macro lens for these photographs (depending on what you are photographing). Make sure you are taking one-to-one photographs in a TIFF or RAW format. You will likely be transitioning to your manual camera settings for these photographs.
For one-to-one photographs, you will want to use a tripod. The tripod will give the camera stability. Hand holding the camera can lead to blurry images, which you want to avoid when the minute details are important. Set the tripod up so that the camera lens is perpendicular to the item you want to photograph.
Before taking photographs, you will want to check that your camera is truly perpendicular using a bubble level. Set the bubble level on the camera and adjust as necessary until the camera is perfectly perpendicular to the item being photographed.
Before you take your photographs, you will want to have your light source ready to go.
All one-to-one photographs should include a scale. The scale should be placed next to the item being photographed on the same plane as that item.
Fill the entire frame of the photograph with the item you are wanting to capture. The scale should be visible at the edge of the photograph. Take multiple photographs of the item, moving the light source around to capture as much detail as possible.
Before moving on, check the photographs you have taken to ensure you captured what was needed. If you did not, go back and photograph again while you have the chance to.
REFERENCES
Dutelle, Aric (2020). An Introduction to Crime Scene Investigation. Jones & Bartlett Learning.
Fish, Jacqueline et al (2014). Crime Scene Investigation. Routledge.
Fisher, Barry & Fisher, David (2012). Techniques of Crime Scene Investigation. CRC Press.
Gardner, Ross & Krouskup, Donna (2018). Practical Crime Scene Processing and Investigation, Third Edition. CRC Press.
Maloney, Michael & Housman, Donald (2014). Crime Scene Investigation Procedural Guide. CRC Press.
Ramirez, Christine & Parish-Fisher, Casie (2011). Crime Scene Processing and Investigation. CRC Press.
Standard Guide for Crime Scene Photography. OSAC Video/Imaging Technology & Analysis Subcommittee (2020, June). Retrieved August 15, 2021 from OSAC Site.