CROWLE'S DOUBLE STAIN

Return to: Main Page   ||  Non-Porous Surfaces  ||  Blood Enhancement Techniques  ||  Metal Surfaces  ||  Glass Surfaces  ||  Plastic Surfaces  ]

Chemical Name:
CROWLE'S DOUBLE STAIN
Surface Used On:
Non-porous surfaces.
Sensitive To:
Latent print residue and Blood components.
Development Color: Method to Record: Hazard: Protective Clothing: Fume Hood Use:

Blue

Yes
Reagent Characteristics

Development Complete When:

Source of Error:

Incompatibilities:

Precautions:

Storage Container:

Safety:

Recommendations:


Similar Reagents



Sequential Reagents
(Not necessarily in this order.)



Abridged Reagent Sequence


Visual Examination
|
Forensic Light
|
Ultra-violet light
|
** Crowle's Double Stain **
|
Forensic Light
|
Amido black

CROWLE'S DOUBLE STAIN FORMULA:
DEVELOPER SOLUTION:
(Mix until dissolved)

 2.5 g Crocein scarlet 7B
150 mg Coomassie brilliant blue R
 50 ml Glacial acetic acid
 30 ml Trichloroacetic acid	

Dilute above mixture into 
1 Liter of distilled water.
Use a stirring device until
all the dye is dissolved.

RINSE SOLUTION:

 30 ml Glacial acetic acid
970 ml distilled water

PROCEDURE OF APPLICATION
1.
Spray, immerse, or use a squirt 
bottle to apply the Developer 
solution to the item.

2.
Wait 30 to 90 seconds.

3.
Apply the Rinse solution.

4.
Repeat these steps if 
necessary to obtain 
maximum contrast.

5.
Photograph the final result.


Ridge Detail Visualized by:

Visible chemical/stain reaction.


Reagent Applicabilities:

Porous surfaces
Non-Porous surfaces
Blood Enhancement


Other Chemical Name(s):

None


Working Solution Shelf-life:

Indefinite

Process Summary:
A stain reagent used to enhance bloody impressions that are visible, and to develop latent prints. The technique consists of a developer solution and a rinse solution. Water is used as a final rinse.
Accepted Deviations:
Tap water may be substituted for distilled water in the Rinse solution if necessary.
Supporting Reference Materials:
1. "Chemical Formulas and Processing Guide for Developing Latent Prints", U.S. Dept. of Justice, pg. 47-48, 1994.

Return to: Main Page   ||  Non-Porous Surfaces  ||  Blood Enhancement Techniques  ||  Metal Surfaces  ||  Glass Surfaces  ||  Plastic Surfaces  ]