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Whenever you dye any sort of textile fiber, some of the dye will attach to the fiber, and some will not. It's extremely important to remove the unattached excess dye. If you don't wash it out, then the loose dye will "crock", that is, rub off onto furniture, skin, other clothing, and whatever else it rubs against, even when it is completely dry.
You can use hand-washing to remove the excess unattached Procion MX dye. Before doing so, be sure to allow an excess amount of time in a warm place for the dyes to react, so that there is no unreacted dye left at all; unreacted dye could leave permanent staining on lighter parts of the design.
For the first step in washing out, rinse the garments with room-temperature or cool water until you see very little color in the rinse water.
For the second step, you will need hot water, the hotter the better. Use a thermometer to check the temperature of your hot tap water as it comes from the faucet. If it is below 140°F (60°C), then you will need to heat water on the stovetop. Higher temperatures are more effective for removing unattached excess dye; boiling water is the most effective, and will not break the bonds between the properly attached dye and the fiber. This is true only for fiber reactive dyes, when they've been set with soda ash or another high-pH chemical; all other dyes must be treated much more gently.
Allow the dyed garments to soak in the hot water, stirring occasionally. For greatest efficiency, devote a cheap styrofoam cooler to this soaking process, so the water does not cool quickly. Use a small amount of detergent, only about half a teaspoon of Synthrapol per pound of fabric. Repeat the hot water washing until you can press a piece of the dyed fabric dry with a hot iron between two white cotton cloths, without seeing any color transfer.
It's considerably less trouble to wash out a number of dyed items in the washing machine. If you have allowed enough extra time to be sure that all of the dye has reacted, with either the fiber or the water, then you won't have to worry about color transfer from one piece to another; 24 hours at 70°F (21°C) or higher is sufficient. Dye that transfers after all of the reactions have completed can be removed by washing in very hot water. You may still want to wash very delicately-colored pieces separately from very dark-colored pieces.
What I do is fill a top-loading washing machine with cool or room-temperature water, and either a small amount of Synthrapol or no detergent at all, and drop my dyed items directly into the washing machine without rinsing them first. I use a pair of blunt-ended child's scissors to cut rubber bands off as I drop them in. I run the clothes through one wash cycle, then turn the water temperature to high and run two wash cycles on hot.
Some washing machines attempt to save energy by adding cold water to even the hot cycle. Needless to say, this wastes more energy than it saves, if it means that the water is not quite hot enough to do the job, so that many more wash cycles are needed. In order to get water at the recommended temperature of 140°F (60°C), it may be necessary to turn off the faucet for the cold water supply to the washing machine, then turn it back on when you are finished.
If your water is hard, the calcium ions in it may form larger complexes with the dye molecules, making the dye much more difficult to wash out. Adding water softener to dye mixtures and to wash water can prevent this problem. See "Dyeing with hard water: water softeners, distilled water, and spring water".
The number one cause of trouble washing out Procion dye is washing in water that is not hot. Water that is 140°F (60°C) is the US standard, but many people turn their water heaters down to reduce the risk of scald inuries to children. Take an immersible thermometer and hold it under the water as it runs into your machine, so that you know whether it is as hot as you need. If you turn up your water heater temporarily, place a note of warning on every faucet in the house, and don't forget to turn it down again when you are done.
However, if you're dyeing something that must not be exposed to hot water due to shrinkage, you can wash out most of the excess dye with several washings in whatever water temperature the item can tolerate. This will be sufficient to prevent crocking (in which inadequately rinsed dye rubs off even after the item is dry). Be careful to launder such an item separately, so that any excess dye that has not been removed does not run onto and ruin other items.
If you are dyeing non-PFD clothing or fabric, it's possible that it has been sized with starch. Starch is a huge problem because it is so difficult to remove. Not even boiling will remove starch. Since starch contains the same glucose building blocks as the cellulose in cotton, it will be dyed just like the fiber; however, the dyed starch will then gradually bleed out with every washing, making it look as though your dye was not properly bound to the fiber in your fabric. The only answer to this problem is not to dye fabrics that have been sized with starch. You can detect starch in white fabric by applying a single drop of tincture of iodine (available from the pharmacy for use as an antiseptic; don't use betadine, which is different). If starch is present, then the color will change to a deep blue or black, but if there is no starch the iodine will stay yellow or orange.
The biggest drawback to fiber reactive dyes is the large amount of water required for washing out the excess unattached dye. Procion MX dyes, as the first fiber reactive dyes to be developed, require more water than other fiber reactive dyes.
What can you do if you need to conserve water while using Procion MX dyes? Note that hotter water is more efficient at removing dyes, because it reduces the dyes' substantivity. After completing one washing with cool water, use hotter water for washing, and try longer periods of soaking. For greatest efficiency, use a cheap Styrofoam cooler, dedicated for use with dyes instead of food, as a container to soak your dyed fabrics with water that you've heated on the stove. The insulation allows the water to stay hot longer, so you can get the most good out of it possible.
Some dyes never attach very firmly to the fiber, so they must be washed out gently, lest you strip out all the dye. Fabric or yarns that have been dyed with most acid dyes, for example, should be washed in water that is no hotter than 105°F (40°C). Leveling acid dyes, in particular, run very easily in the wash and must be treated very gently, washing only with cool water, and washing separately to avoid ruining other garments with the run-off; even with gentle treatment, these dyes will tend to run in the laundry. The same is true of direct dye. Both leveling acid dyes and direct dyes are found in all-purpose dyes, such as Rit, which is why the makers of Rit advise you to hand-wash all Rit-dyed items separately in cool water. Fiber reactive dyes are much safer in the wash.
Your choice of dye makes a huge difference in how you can wash your dyed items later. Fiber reactive dyes, such as Procion, Remazol (vinyl sulfone), and Drimarene K dyes, form such a strong chemical bond to natural fibers that they do not wash out, even if subjected to boiling water. Only the excess unattached dye molecules will wash out. Once those have been removed, the remaining dye molecules are permanently bound. Good tie-dye kits contain Procion MX type dye.
If you can't use a fiber reactive dye, but instead must use a less washfast (i.e. less wash-resistant) dye, try a cationic dye fixative, such as Retayne. See my page, Commercial Dye Fixatives. Cationic dye fixatives improve washfastness, but often at the expense of reduced lightfastness, resulting in more fading from exposure to the sun. They work on all negatively charged dyes, including most acid dyes, direct dyes, and inadequately bonded or inadequately washed-out fiber reactive dyes.
Last updated: August 2, 2012
Page created: August 1, 2012
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