Alexander Fehrmann is a Trainer and Technical Support Specialist at Amped Software. With a background spanning police forensics, professional photography, and advanced imaging technologies, he brings extensive expertise in forensic photography, 3D imaging, and video forensics to his role.
Mr. Fehrmann, thank you for joining us. Fingerprints have been a cornerstone of forensic science for ages. Could you shed some light on their significance in modern investigations?
Absolutely. Fingerprints are unique to every individual and remain unchanged throughout life. That permanence makes them invaluable in criminal investigations; they can definitively connect a person to a scene. In fact, in some cases, they provide more conclusive evidence than DNA.
That’s fascinating. I understand that Amped FIVE is widely used to process fingerprint images. How does it help analysts?
Amped FIVE is a comprehensive forensic software suite. It enables analysts to enhance and clarify prints, even when they’re faint or captured under challenging conditions. With filters to fine-tune exposure, contrast, and other parameters, fingerprints can be made clearer and more detailed for reliable analysis.
Could you walk us through the typical workflow?
We begin by importing the fingerprint into Amped FIVE and assessing quality, checking for underexposure or overexposure. Next, we adjust brightness and contrast to make the ridge detail stand out. If the print sits on a colored or patterned background, we often convert to grayscale and apply filters to isolate it. Finally, we ensure accurate scaling with the Resize 1:1 filter, so measurements reflect real-world dimensions.
Why is scaling so important?
Because any comparison must be made at true size. If the fingerprint image isn’t calibrated properly, measurements can be misleading. Amped FIVE allows us to use a known reference length, so evidence is always accurate in court.
And what about prints on complex backgrounds?
That’s where tools like the Channel Mixer and Fourier filters shine. They help reduce distracting background patterns and emphasize the fingerprint itself.
With so much enhancement, how do you preserve integrity?
That’s fundamental. FIVE follows a non-destructive, fully documented workflow. Every action is logged, ensuring transparency and reproducibility.
And when it comes to presenting the results in court?
Analysts can annotate images, add case details, and export clear, professional visuals. Combined with the full report of processing steps, the evidence remains admissible and understandable to a jury.
That makes sense. Now, we always hear a lot about fingerprints and DNA, but what about other types of impressions? For example, are shoeprints really that useful?
Absolutely. Footwear impressions can identify not only a shoe type, but sometimes a specific pair, thanks to unique wear patterns. They also map movement—where someone came from, where they went, and what they did. Every step tells a story.
So, before you even touch the software, what’s the first thing you do when you encounter a shoeprint?
Photography. We capture both overview shots to show context and close-ups of the tread pattern. That context turns a mark into evidence.
And then you document it in FIVE?
Exactly. We use tools like Annotate for labels and Magnify for details. If we want to keep the print clean, we extend the canvas so the text sits neatly outside the image. It keeps everything clear for investigators and jurors.
But what if the print is barely visible?
Lighting is key. Shooting straight-on reduces distortion, while angled light sometimes highlights detail. When glare is the problem, cross-polarized flash—using polarizers on both lens and flash at 90°—eliminates reflections so the print stands out.
Once you have the photographs, how do you process them in FIVE?
It’s systematic and transparent: invert the print with Negative, carefully improve contrast with Smart Adjust, convert to grayscale to focus on shape, scale the image 1:1 for true-to-life printouts, add orientation markers and labels, and then use Video Mixer to compare scene prints with suspect shoes side by side.
And of course, everything needs to be documented.
Yes indeed, FIVE generates a detailed report of every filter, parameter, and step, complete with scientific references. That ensures reproducibility and courtroom credibility.
It sounds like shoeprints can reveal a lot more than people might think.
They really can. With proper photography, smart lighting, and a reproducible workflow, even faint impressions can be transformed into life-size, courtroom-ready exhibits.
And it’s not just shoes, right? In forensics, we often hear the phrase “every contact leaves a trace.” What does that really mean?
It comes from Edmond Locard. Whenever two surfaces touch, they exchange clues. Shoes on soil, tires on asphalt, pliers on paint, teeth on skin—all can leave impressions. Combine that with the “Principle of Individuality,” which says every object is unique, and you see why impression evidence is so powerful.
So these marks can actually point to a specific person or object?
Often, yes. If we document and process impressions properly, we can compare a questioned trace to a known source, say, a specific tire or dental pattern, and evaluate how strongly they match.
Tire marks are a good example. If an officer takes a quick photo at the scene, what happens next in FIVE?
We start by fixing exposure so the mark isn’t too dark or too bright. If the photo is taken in a plane-parallel way and a scale is visible, we calibrate with Measure 1D and can then measure tread width precisely. If the photo was taken at an angle without a ruler, we use Correct Perspective with a known rectangle and then switch to Measure 2D for accurate dimensions.
And how about tool marks?
Tools like pliers leave distinctive jaw patterns. By enhancing contrast and sharpness in FIVE, those fine details can be compared to a suspect tool.
Bite marks sound even trickier. Can they really be used to identify someone?
They can, if documented correctly. A scale is essential. Without it, a photo may be useless. With it, we can enhance details in FIVE, preserve measurements, and prepare side-by-side comparisons.
I’ve also seen cases where investigators bring out writing impressions from sheets of paper underneath. Is that really possible?
Absolutely. It’s called indented writing. The gold standard in labs is ESDA, but if you only have a photo, FIVE can still help. Histogram Equalization boosts subtle indentations.
So the recipe is always the same: start with good documentation, then apply careful, explainable processing.
Exactly. Document with scales, correct perspective, make small, traceable adjustments. Even faint traces become measurable, courtroom-ready evidence.
If you had to leave investigators with just a few reminders, what would they be?
Three essentials:
- Always include a scale if comparison is possible.
- Correct perspective before measuring.
- Make small, documented adjustments while monitoring the histogram. Your future self and the court will thank you.
Thank you, Mr. Fehrmann, for walking us through this fascinating world of impression evidence.
My pleasure. Whether it’s fingerprints, shoeprints, or other impressions, Amped FIVE helps ensure that the smallest trace can speak clearly in the pursuit of justice through science.
To all professionals out there, you can check our blog for more insights on these topics and read the full blog posts on fingerprint analysis, shoeprint analysis and processing impression evidence in Amped FIVE.
Thank you!
