On almost every jeans manufacturer's web site or brochure you will read the term "washings". What does it actually mean and what kinds of washings are there?
To list all the washings that we have been asked to do before would probably take a few weeks and several pages to list, so we'll just talk about the most well know washings first.
Rinse (water) wash: Speaks for itself mostly. Like in the good old days the jeans will be washed at about 50 degrees Celsius. High risk of color bleeding, so ideal to use for brightening up your old faded jeans by washing them together. Make certain to wash separate from other garments the first few times. Some Jeans brands will even not use sanforized fabric, so that you can shrink them to fit in a hot bath. This was (again) very popular back in the 80's.
Stone wash: Still the most famous of all washings. The jeans are washed with oval or round pumice stones which should all have roughly the same format. The pumice stones are very light with a rough surface. Sometimes, when the final quality inspectors at the jeans factory forget to clean the pockets, you may even find some residue of these stones in the pockets of your new jeans. During the washing process these stones will scrap off a thin layer of the denim does showing some of the white threads from the part of the cloth where the indigo dyeing stuff was not able to penetrate. It also creates and effect called brilliance. You may also encounter words like deep stone or super stonewash, which are an indication of how long the jeans have been stonewashed. Ergo:
The longer the wash, the lighter the jeans.
Overdye: An additional dying after the jeans have been sewn. This ensures a very deep dark or black color and makes the sewing thread blend in with the jeans color.
After stonewashing the jeans or denim jackets, they will be dyed with special chemicals thus creating a look in which the jeans will appear to be dirty.
Destroyed / Damaged / Used / Whiskers:
There are several different techniques to make the jeans or denim jackets look old, worn and /or used. Most of these techniques involve actual sandblasting or abrading by some kind of power tool. Whiskers, which normally appear around the hip to crotch area of the pant, are usually made by using a grinder. Another popular way to make jeans appear damaged is to cut the edges at bottom, (back-) pockets, fly and knee area before the (stone)washing.
Laser marking / spray painting / etc:
From the high-tech side there has been a renewed interest in the jeans and garment industry in general. A few of the very cool new inventions are: the jeans laser marker and the Jeans spray robot, as shown below. However, due to the relative high cost of these machines they are hard to find in these parts of asia.