Treatment of glossy cardboard boxes

[antonroland]

Hello all

Calling on all latent print lab technicians willing to assist...

I have noticed that many cardboard boxes in the retail sector have very nice and glossy exteriors but porous insides which soak up the Rhodamine and this causes the exterior to react with an unusually high uniform degree of background noise luminescence.

I have thought of and experimented with several alternative workflows and would like to hear how others do it.

Option 1 would be to dust the exterior carefully and treat the inside with ninhydrin.

Alternatively, to fume the exterior and do a visual inspection of unstained CA prints before applying ninhydrin.

Even doing so carefully, I cannot see that spraying ninhydrin on the insides could work before fuming as I believe that there is a strong possibility of damaging latents on the glossy exterior.

Any input appreciated.

Cheers all

[Gerald Clough]

As a fingerprint evidence processor, I'm just a country boy who mostly worked with the basics. But if I were presented with the typical product packaging with the slick coated printed side and a porous inside surface, and I considered both sides likely to bear impressions, I'd consider contact ninydrin, the "sandwich" or "dry" method using impregnated paper, for the porous back and CA for the slick front. I've not actually done that combination, so I'd do some test runs on control samples to work out any protections of one surface while treating the other.

[sharon cook]

Superglue first--it won't hurt any latent prints on the inside cardboard part--then magnetic powder on the outside glossy surface. That glossy cardboard still has a tendency to soak up regular powder and kind of "paint" the surface, so I always use magnetic powder. You might also want to try "huffing" as you ply the magnetic powder. I've have had good success with that method. Then ninhydrin the inside surface. Good luck!

[antonroland]

Thanks very much folks.

Will give it a go. Sharon, must admit not to know what huffing is...please enlighten me

[sharon cook]

"Huffing" is when you blow a deep lungful of warm moist air (mouth open, NOT pursed lips), on the surface and then quickly draw the magnetic particles across the surface ONCE only! If there is ridge detail there, it will show up in the first sweep, but may disappear if you sweep back across the print. I have developed great prints on plastic bags, PVC pipe, glossy cardboard, and other surfaces that tend to be painted when using regular powder. You need to wait a split second after blowing and before sweeping the particles to let most of the moisture, (but not all of it), dissipate. It will take some practice. Good luck!

[Neville]

Hi Anton

When we first started using the Laser at Auckland Uni we made a habit of checking the best wave length to use on a given item before applying staining, this followed through when we got our first Rofin Polilight. The idea was that we would then know at what wavelength the background would fluoresce, then choose a stain that fluoresce outside that wave length.

You could try DFO and have the best of both worlds, just make sure you use very clean trays. I guess you are talking serious crime. There is Safronine-O (not sure if I spelt that right) and basic yellow to mention some common ones. These three all fluoresce at different wave lengths.

Don't forget the dry ice treatment as it can bring up those faint prints. And of course very long exposures, sometimes we got up to 5 minutes, but with digital we took mulitiple shots and added them together using the software.

If its basic stuff and fresh latents go with the magna powder, magna ruby works on fresh prints on plain cardboard.

Happy hunting.

[antonroland]

Thanks again folks.

I should be on a bit more regularly now again as I have just finished a week on the road.

Have a great week all!