Cargille PCB-Free Immersion oils were introduced in 1972. Today, no other immersion oil meets FDA criteria.  Now four standard types are available with the introduction of Type NVH, a very high viscosity oil. All Cargille Immersion Oils meet DIN 58 884 (Deutsche Institut Fur Normung e.V.).

For normal light mcroscopy: Types A and amp B, with viscosities of 150 and 1250 cSt respectively, meet these requirements. The greater the gap between cover glass and objective, or condenser and slide, the more desirable high viscosity becomes. For extremely large gaps, type NVH should be used. All cargille immersion ols can be blended for intermediate viscosities.

37 °C Immersion oils: A number of research projects require microscopic studies at internal body temperature.   Since the index/temperature relationship is inverse, increasing temperature significantly reduces the index of the immersion oil and consequently the imagery deteriorates.  This problem has been resolved by the formation of Cargille 37 °C Immersion Oils, which have an index of 1.515 at 37 °C. Consideration of these oils is also suggested where stage temperatures are elevated by sub-stage illuminators and high wattage projection equipment.

Immersion oil type 300: Automated hematology systems depend on accurate, precisely controlled physical and optical properties of immersion oil for successful imaging and mechanical processing. Type 300 is designed and manufactured to meet the stringent requirements of this equipment, which include specialized viscosity and exacting controls for its consistency.

High viscosity NVH: For horizontal, inverted and inclined instruments and projection equipment higher viscosities are generally required.  Type NVH meets the requirement, having a viscosity of 21000 cSt.