For crime fiction writers, you won’t need all of this information. However, if it’s tucked away in your mind, what you do need on paper is available to you.
So… fingerprinting. You see it all the time on TV, watched as times have changed. I have trained in the ‘How To Collect Prints’ (the old fashioned way in a rural setting).
Here is an overview of the ‘new’. Technology has changed; a new standard of equipment is the portable scanner over one or more fingers. If you know anything medical, it’s not unlike taking someone’s finger oximetry (which I also know how to do).
The CSU team in the field or medical examiner does this work. The finger of the dead or live victim/suspect is placed into or on a scan, much like your biometric safe where we know you keep your guns… And there are several new techniques even for scanning.
The scan is saved and uploaded to a computer, where the very accurate image is sent to local, state databases to send to AFIS, the Automated Fingerprint ID System (local, county or state) or IAFIS, which is nationally maintained through the FBI. Both AFIS and IAFIS store not just fingerprints, but criminal history.
So, you’d better have a spotless background check before you purchase a gun and/or concealed carry weapon… The DMV is now also sending your picture into state databases by the way, to match you and your prints together.
Yes, we all know that DNA trumps everything (except in identical twins, only fingerprints finalize identity). Circumstances, environment, clothing, and… the smoking gun. We love that smoking gun. Especially in reality. The ‘interview’ involving anyone around the crime scene, knows the victim, or saw everything can be recorded on tape and video without consent because after all, it’s just an interview, no Miranda rights needed (some interview policies are state-based). Good baseline gathering for your evidence.
Back to old-school prints still being used today.
Collecting old-fashioned prints is an art. It can take some time to master how to print, lightly dip into the powder of choice, and lightly twirling the ‘brush’ (I must make my confession. When I was in the learning process, one night after midnight … I printed the kitchen with black carbon powder. My kitchen. I then face planted into bed a good two hours later, and my early riser husband had… a … fit… it gets everywhere, on you, your skin, your dog, etc.).
First… inking the fingers. Use an ink pad and fingerprinting paper. Get the entire pad of each finger blackened and roll each—right after each finger printed. There’s a method to this messy madness.
Your suspect or victim must have clean hands/fingers so dirt particles and grease do not interfere with the process. Hold each finger for both ink and print paper. With the same, light pressure, roll the thumb from the outside to the inside. Fingers, roll onto the paper inside to outside. Outside to insideà if you aren’t sure what I mean, stick your thumb in the air like a thumbs up. Turn it to palm up, other fingers curled. Press the outside first and gently roll to the inside. The opposite for each finger. Make sure they are numbered correctly. Your nerves count. So does the suspect’s. A smudged print is pretty much useless. Palms can be printed, feet, even lips.
After learning to ink and clean fingers, you get to twirl the brush in one hand lightly. Trust me when I tell you , learn to twirl before you have powder on it. Then, dip the brush (for real) into your powder of choice (not too much). Powder of choice is that which you need to dust, and where in the house/scene to print. That’s just part of the job, because trainees practice on their friends, family, co-workers. You’ve got it down, right?
But wait! Before you leave, I have a free special!
Yeah. No, you’re not done. Not even.
Now comes the fun part. You have learned to print an individual walking through your door for a CC license, realtor license, etc. Even a suspect (if they are now in the interrogation and highly suspect… so to speak). Hallelujah.
Now Ms. and Mr. CSU, you’re characters are working a real scene with the printing powder, dusting for latent prints (invisible) and the more *obvious* prints that develop best on porous areas and greasy and dirty hands. Windows, cups, paper. Different powders…
What is print powder made of? Oh, great question. Because there are many types of powder and guidelines on what powder, what to do before the powder, and what to use chemically to enhance a print (to scan when done).
Keep this in mind: A lot of powders (okay, most) require a different, dedicated brush, some black, some white, some feathered. If you are going to use two different types of powders make sure you have a brush for each and a method to keep them separate, not contaminating another. Simple plastic wrap will do fine. Mark them lest you forget which is which.
First and before powder, your scene had better be marked, measured and a numbered placard place next to said print. Then, you photograph … twice. From above and a 45 degree angle, using a 35mm camera and a thumb drive to upload to your computer. Don’t worry about getting extra pictures …. just not of you and your friends at the site.
Done? No. You have your handy field guide to fingerprinting or your cheat sheet… and FBI manual in your kit. What powder to use. After the photos. After all the on site processes take place. Some require sprays or ‘superglue’ on a hot plate in a box… literally sticking to the print (basically this is how it works without all the fancy terms. Got those, too, but processing is another article.).
Do not forget your print tape to lift and a designated placard number. I have two types of tape, but guess what? 3M tape works, not perfect but try it. You place your tape against the appropriate colored background paper and voila! Print in the field is collected–not the process required in the lab. You’ve processed the crime scene for prints. This is just one of the many things that CSU teams go through.
Some officers /CSU use the black, carbon based powder on just about everything, including porous surfaces. Meh, I like to go FBI-style. I have a full kit and every powder available. I have an extensive cheat sheet I made, and FBI handbook. My kit is almost twice as big as the sheriff’s office… and I saw them slathering. White powder is available and useful for windows, dark surfaces such as very dark countertops, chrome, plastic bags. Some are made with aluminum or titanium. Wear your masks for all powder prints, please.
Carbon-based black powder has been the standard until cooler stuff came along. Magnetic powders are my hands down favorite for porous, non-porous surfaces, plastics, Styrofoam and rubber (eyes wide open… don’t forget the tossed condom). For magnetic powder, no brush required, and is easy clean up. Magnetic powder (made from iron) sticks to the oily portions of a fingerprint. It’s truly outstanding. You use a magnet designed for the dropping the powder, and then cleanup… No muss, no fuss, not a lot of left over like carbon powder twirled onto the kitchen walls, plates, cups, wood, counters… ahem.
Special dyes are used for colorants in fluorescing powders to use your Alternative Light Sources with, but take care, these powders can over-process in the field, and yes, the prints are ruined. Got one print, and you just over-processed it? You will be called Dusty the rest of your days. And maybe a kick in the butt. The UV lights require yellow or orange tinted glasses, unless you want cataracts before you reach retirement. Yes, I have two light sources and two sets of glasses… just in case my husband thought one was a flashlight (he did). It’s lost. Do not use fluorescent powders on large surfaces.
Photograph. Occasionally the fluorescing powder requires two people to photograph, and the reason should be obvious. One to shine the light the correct angles and one to get the photos.
Red oxide powders and magnetic oxide powders are used for either dark or light background surfaces, and work well on non-porous surfaces. These are cool because of their versatility. Messy.
Coin box powders. Another fun animal. Use these on metallic surfaces, vending machine, pipes. They require one or two types of ‘smoking’ which are dangerous during lab processing. Leave this to the processing team. By the way, let the processing team work all the prints you’ve collected. Lifting possible ammunition, full or partial prints are best left for the processing team. However, for your fiction, you may get a partial print, thumb and forefinger prints that need special care. You only get one chance.
Brushes: using your feather brush, (different that your carbon based and magnetic brushes). These do well on countertops, wood, and household woodwork (like unpainted doorjambs, decks and lightly painted wood).
Uneven surfaces suck. But that’s where that handy dandy 35mm comes in after you’ve brushed or dropped the right powder. Sometimes they can be processed well with little or no warp.
I haven’t invested in spray powder but the powder spray covers the print more accurately and evenly. It doesn’t replace your powder, but is another cool tool for your kit. If you’re dipping too much powder onto your brush, it’s a mess and your print will be well, useless. That’s when the spray comes in handy.
What about wet surfaces? You see a print in condensation or a wet counter. Use a small particle reagent. This is a liquid powder, sprayed onto the print and the reagent will stick to the print.
The latest powder I do not have are supernano powders made with very fine silica that according to processors, improve print demarcation by 30%. They are processed differently, with lasers. These pick up so much more information than any other print powder that you will want it. Me, too.
My next article will be on processing, including superglue… For now, get an ink pad, print paper (or your home ink pad, regular paper) and start twirling that brush with a bit of powder or dropping a wee clump of magnetic powder to play with. I recommend aprons, gloves and never past your bedtime.
Well, boys and girls, we got a lotta work to do in coming days, weeks, months.
Why is this in Romance tags? Because … what if your characters are in love but er, don’t know it? Bicker?
If you know of more printing techniques and / or glaring errors, that I have not covered, errors, do give me a comment on my website blog. I’ll hit up the stores for more to put in my kit, correct my work and give you the credit. 🙂