Confused about chemical names of mordants and assistants etc? Check the Chemical Names page!
Dithionite. Can I use Dithionite instead of Spectralite? How should I use Dithionite?
Sodium dithionite is widely used in Europe as a safe alternative to spectralite for chemical dyeing with woad & indigo. You can substitute sodium dithionite where spectralite is mentioned in the text but you will need to double the quantities because sodium dithionite is not as strong. More about dithionite here.
Dust Mask/Face Mask ratings - What is the difference between FFP1 and FFP2 dust masks?
Our dust masks are mechanical filter respirators that retain particulate matter when contaminated air is passed through the filter material. Wool is still used today as a filter, along with other substances such as plastic, glass, cellulose, and combinations of two or more of these materials. Since the filters cannot be cleaned and reused and therefore have a limited lifespan, cost and disposability are key factors.
An FFP2 dust mask will offer greater protection than an FFP1 rated face mask and both will offer safer protection than unrated masks.
An FFP1 dust mask has an Assigned Protection Factor (APF) of 4, and an FFP2 face mask has an APF of 10.
European standard EN 149 defines the following classes of “filtering half masks” or “filtering face pieces”), that is respirators that are entirely or substantially constructed of filtering material, hence the ‘FFP’ in the name of the class of filter:
FFP1 Filters at least 80% of airborne particles
FFP2 Filters at least 94% of airborne particles
FFP3 Filters at least 99% of airborne particles.
Top of page