Fingerprinting

[vlclabbie]

Hi all! We have a fingerprinting prac tomorrow & one uses gentian violet (seeing latent prints) - we don't have any (typical!) so I was wondering what everyone else uses? Thanks!

[ri]

Just stamp pads

[Rowyrow]

Just get them to colour in their finger with a texta and print onto paper, Kept me occupies in school!

[bindibadgi]

Eeeeek!!!

Don't let them use gentian violet! The stuff will turn anything that comes into contact with it, including the kids, purple for weeks
Entertaining, but a real pain to try & clean up.

We do junior forensic pracs & get fingerprints by rubbing a pencil (6B works great) on a piece of paper, lifting the prints off with sticky tape & smoothing the tape onto a white card.

[smiley]

We do a variety. Firstly we rub ordinary pencil on very fine sandpaper, the kids put their fingers on it, then press them onto white paper. We compare that with charcoal (or the old carbon blocks that are in my storeroom). We do stamp pads and white paper. We do chalk on black paper, and finally we do fingerprints on new pieces of OHP sheet, and develop them in a fish tank with ammonia and superglue.

[Lyn]

Latent prints -
shiny black surface or garbag - dust with calcium carbonate
shiny clear surface - use black powder (carbon is a bit of a no no)
filter paper - I have glass jars that students hang strips of filter paper over edge of jar which has a small amount of iodine crystals in the bottom. Screw lid on and watch the fingerprint appear. Make sure they have wiped their finger across the bridge of their nose, forehead or face ie, wherever they have any oily skin before they make their print on the filter paper.
shiny hard surface - super glue will show prints if hard surface is enclosed within a container which has super glue added to it. It's the fumes from the super glue which show up the prints.
Lyn.

[Voice]

If you really do want Gentian Violet then maybe the local pharmacy might have some to sell (they used to). It is also called Crystal Violet.
Maree

[Robdean]

Ha, I remember at uni when we were doing a prac assessment identifying bacteria when the lecturer sidled up to me and advised me not to touch my face again as I'd just put a big splotch of crystal violet on my cheek!! Didn't I feel silly! It did take some time to wear off!!

[vlclabbie]

Thanks everyone

Yup was after gentian for latent prints - you don't put them on your fingers, you use it to develop invisible prints.

Some fab ideas!

Cheers, Kel

[Lyn]

Can you post the procedure for using gentian violet to process latent fingerprints please. I haven't heard of this particular prac and would be interested to try it out and perhaps suggest it to the teachers if it works well.
Thanks, Lyn.