può essere 'solventi concentrati diluiti'?
Cut = anche diuito/tagliato con acqua ad es.
narrow = stretto anche in senso di concentrato

Hi Ilde
I took a look around and found a few references to "narrow cut solvent" in English, one of which linked up to a Mobil site. Investigating further in Italian I found the link I am posting, which may or may not be relevant.
Cheers
Derek

Non so se ti può aiutare :

DISTILLATION TEST - method for determining the full range of volatility characteristics of a hydrocarbon liquid by progressively boiling off (evaporating) a sample under controlled heating. Initial boiling point (IBP) is the fluid temperature at which the first drop falls into a graduated cylinder after being condensed in a condenser connected to a distillation flask. Mid-boiling point (MBP) is the temperature at which 50% of the fluid has collected in the cylinder. Dry point is the temperature at which the last drop of fluid disappears from the bottom of the distillation flask. Final boiling point (FBP) is the highest temperature observed. Front-end volatility and tail-end volatility are the amounts of test sample that evaporate, respectively, at the low and high temperature ranges. If the boiling range is small, the fluid is said to be narrow cut, that is, having components with similar volatilities; if the boiling range is wide, the fluid is termed wide cut. Distillation may be carried out by several ASTM test methods, including ASTM D 86, D 850, D 1078, and D 1160.

Ciao, Jean-Marie