Depending on the location of the window to be dressed you may not need a truly waterproof fabric. If the blind is very close to the shower then it may run the risk of getting wet. In this case it may be worth choosing a pvc fabric. This is waterproof and wont be damaged if it gets wet.
In all other cases the worst a blind will have to put up with is condensation. As long as the bathroom is well ventilated by either an open window or an extraction fan then most fabrics would be fine in this environment. Try and avoid a fabric with a flock such as faux suede material as this would hold moisture for longer that could possibly encourage mould growth over time.
If the location of your bathroom demands privacy then you may want to consider a privacy blind. Typically a blackout fabric or even a venetian blind will offer a window covering that will offer the most privacy even when the bathroom light is on in the evening. The PVC blind that we mentioned as being waterproof is also blackout so this would serve both functions.
Type Of Blinds
What type of blind that you choose is down to personal choice, roller blinds and vertical blinds are available in all the fabrics that we've mentioned, both are ideal as bathroom blinds, in a dark bathroom then a roller blind will allow more light in during the day whereas vertical blinds will offer better light control on larger windows or windows that have the sun during the day.
Venetian blinds can look great in the bathroom, It may be advisable to avoid real wood venetians but aluminium or wood effect venetian blinds are ideal.
Pleated or Roman blinds, aren't really ideal in the bathroom as they would be affected by moisture.
Vertical, roller and venetian blinds then seem to be the best choice for a bathroom, all are available in a wide range of colours and shades that will blend or harmonise with your colour scheme. Click here to see a range of affordable blinds ideal for bathrooms.