Sebaceous Residue
Definition
The oily secretion from sebaceous glands, containing triglycerides, fatty acids, squalene, and waxes, that makes up an increasing proportion of aged latent print residue as the aqueous fraction evaporates.
- Source
- Sebaceous gland secretion
- Composition
- Triglycerides, fatty acids, squalene, waxes
- Aging behaviour
- Proportion increases as the aqueous fraction evaporates
- Relevance
- Latent fingerprint residue composition and lifting method choice
Common questions
Why does the aging of a latent print favour sebaceous over aqueous residue?+
Fresh fingerprint residue is a mixture of watery eccrine sweat and oilier sebaceous secretion, but the watery component evaporates within hours while the sebaceous fats and waxes persist far longer, so an older latent print is proportionally richer in sebaceous material even though the total residue amount decreases.
How does knowing a print is sebaceous-dominant change which development technique an examiner picks?+
Sebaceous-rich residue responds well to powder methods and to techniques that target lipids, such as certain fuming or dye-stain processes, whereas methods optimized for the amino acids in fresh eccrine sweat, like ninhydrin, become less effective as a print ages and loses its aqueous fraction.
Does sebaceous residue composition vary between individuals in a forensically useful way?+
There is measurable person-to-person and even body-site variation in sebaceous output and composition, which researchers have explored for chemical profiling alongside ridge detail, though this remains a supplementary line of evidence rather than a standalone identification method.
Related terms
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- A two-component powder mixture containing both black and white particles that produce visible contrast on substrates of mixed or uncertain reflectance.
- Eccrine Residue
- The water-based secretion from eccrine glands in friction-ridge skin, containing water, amino acids, salts, urea, and lactic acid; the primary component of...
- Gel Lifter
- A tacky gelatin sheet used to transfer developed fingerprint impressions from textured or three-dimensional surfaces where conventional adhesive tape would not conform;...
- Hinge Lifter
- A pre-assembled lifting unit in which a clear acetate film hinged to a backing card is folded over a developed print, pressed,...
- Magnetic Powder
- An iron-oxide-based latent print development powder applied with a magnetic wand rather than a brush, making near-zero contact with the substrate surface...
- Magnetic Wand
- A stylus containing a retractable internal magnet that draws magnetic powder into a cluster at the tip for application to surfaces; retraction...
- Non-Porous Substrate
- A surface (glass, gloss metal, polished plastic) that does not absorb latent print residue, retaining it on the surface and making it...
- Porous Substrate
- A surface (paper, uncoated cardboard, raw wood) that absorbs the aqueous component of latent print residue into its matrix, making powder development...