How can I be sure a new article of clothing is colorfast and what is the test when using color safe bleach?
This is mostly common sense, but there are also some simple tests that take very little time to be sure your clothing is not damaged when washing or bleaching.
With a new article of clothing, especially on vibrant colors, always do this quick test before washing for the first time. Moisten an inside seam, and rub with a white cotton towel or a cotton ball. If any of the color transfers to the white cloth or ball, treat this article of clothing like dynamite. It has the potential to turn sports socks pink, make blue jeans purple, and other wise ruin perfectly good clothing.
Wash separately, according to the manufacturers label. One garment can be easily laundered in a sink to save energy, instead of running your washer with only one piece of clothing in it! Wash in cold water to prevent the dye from running out, and follow the label for drying. If the clothing cannot be placed in a dryer, wrap it up in an old terry towel, to remove as much moisture as possible, before laying flat to dry. Hanging a non-colorfast garment to dry, may leave dye run marks. For articles of clothing that can be placed in a dryer, the heat will usually set the color, making the piece colorfast, but to be certain, re-test before the next laundering.
As for bleaches, the two most common types are chlorine (whites) and oxygen (all-fabric) based. For either of these you will mix a small amount to use as a tester. For whites mix a tablespoon of chlorine bleach in a cup of water, for colors mix 1 teaspoon of all fabric bleach to a cup of water. Place a drop on an inside seam, or on a shirttail. Allow the drop to sit for 5 to 10 minutes, and check to see if the color has lightened. If it does not change color, it is safe to treat with that type of bleach. You can add the remaining test mixture into the wash water, but always be sure to follow the manufacturers directions for dilution rates.
The complete list of what all those laundry symbols stand for can be found at http://www.textileaffairs.com/lguide.htm