Taenzer-Unna Orcein
for Elastic Fibres


Orcein solution
Orcein 1 g
Ethanol, 70% 100 mL
Hydrochloric acid, conc. 1 mL
Acid ethanol
Ethanol, 70% 100 mL
Hydrochloric acid, conc. 1 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory.


  1. Bring sections to water via xylene and ethanol.
  2. Rinse with 70% ethanol.
  3. Place into orcein solution for an appropriate time.
  4. Optionally, treat with acid ethanol until collagen is unstained (a few seconds).
  5. Wash with water
  6. Counterstain if wished.
  7. Dehydrate with 95% and absolute ethanols.
  8. Clear with xylene and mount with a resinous medium.

Expected results


  1. Gray specifies 0.8 grams orcein, most others specify 1 gram.
  2. Gray specifies 50% ethanol, Culling 70% and Carleton 80%. Others have recommended concentrations ranging from 65% to 100% (Lillie).
  3. Staining times specified include 6-12 hours (Gray), overnight (Culling) and 30 minutes to 2 hours (Carleton).
  4. Elevating the temperature (37°C Carleton, 56°C Culling) decreases staining time.
  5. Recommended counterstains are van Gieson, methylene blue, H&E.



Gray, Peter. (1954)
The Microtomist's Formulary and Guide.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.
    von Kahlden, C., and Laurent, O. (1896)
    Technique microscopique.
    Carré, Paris, France

Drury, R.A.B. and Wallington, E.A., (1980)
Carleton's histological technique Ed. 5
Oxford University Press, Oxford, UK.

Culling C.F.A., (1974)
Handbook of histopathological and histochemical techniques Ed. 3
Butterworth, London, UK.

Mallory, F. B. & Wright, J.H., (1904)
Pathological technique, Ed.3
W. B. Saunders, Philadelphia, USA.

Lillie, R.D., (1954)
Histopathologic technique and practical histochemistry Ed.2
Blakiston, New York, USA.




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