à ma connaissance tu as deux marques de colophane qui pourraient te convenir.
La Larsenqui est sensée être testée dermathologiquement pour ne pas provoquer d'allergie.
et la Super sensitive Clarity qui est une colophane de synthèse donc qui ne contient pas de résine d'arbre.
on trouve la larsen bien plus facilement que la clarity ces deux colophanes sont assez chères en particulier la larsen..
edit: plus d'info (en anglais)
Clarity a écrit : Traditional Bow Rosin Compared to Clarity®
from Super-Sensitive Musical String Company
Gum rosin has been used for centuries to create friction between stringed instrument bow hairs and the strings of instruments like violins. Rosin is typically supplied in a small cake form that is rubbed onto the hairs of a bow in order to give the bow hairs enough tackiness to cause the instrument strings to vibrate when rubbed across the strings. It is the vibration of the strings that causes the sound of the instrument.
Rosin is a hard, brittle, naturally occurring substance derived from the distillation of oil of turpentine, which is itself derived from pine trees. It is primarily comprised of abietic acid, isomers of abietic acid, and numerous other naturally occurring compounds. Because it is naturally derived, and because of its organic acid chemical structure, rosin has at least five distinct drawbacks:
1. Rosin is hydrophilic and absorbs water. This causes the tackiness of the rosin to vary according to ambient humidity, which affects the sound of the instrument.
2. Rosin is susceptible to oxidation. Rosin becomes a fine powder when applied to bow hairs. This powder has a high surface to volume ratio and rapidly reacts with ambient oxygen. As rosin oxidizes, it loses tack and essentially loses its effectiveness.
3. Rosin is a naturally occurring material, derived from pine trees, and causes allergic reactions in susceptible people.
4. Rosin is primarily an organic acid and potentially corrosive. Rosin dust typically accumulates on the surface of the instrument and bow and can corrode the wood’s varnish.
5. Being a natural product, the properties of rosin vary significantly from season to season and from one geographic location to another. It is very difficult to control the quality and consistency of gum rosin based products.
Clarity® bow resin (patent pending) has been formulated to overcome these drawbacks. It is based on a blend of synthetic polymers that are derived from petroleum based hydrocarbons. The materials in Clarity® are extremely pure, highly controlled, and benign polymers. The Clarity® materials are from a family of polymers that are commonly used as components in adhesives for medical applications, baby diapers, and feminine hygiene products. They have been extensively tested for skin irritation and allergenic effects and have been found to be generally safe.
These substances improve upon the properties of rosin in at least five ways:
1. They are hydrophobic. They resist the absorption of water and their tack is nearly unaffected by ambient humidity. This results in a more consistent sound regardless of humidity.
2. They are saturated hydrocarbon compounds that are resistant to oxidation. They are virtually non-reactive with ambient oxygen, even in a finely powdered form, and thus resist losing their tack or effectiveness over time.
3. They are synthetic materials, significantly less prone to being allergenic than rosin, and can be considered hypo-allergenic.
4. They are chemically inert with regard to instrument varnishes and do not corrode the varnishes.
5. They are manufactured under tightly controlled conditions with negligible lot-to-lot variation. Products based on them have very high consistent quality.
