Monthly Archives: July 2014

Will synthrapol remove color from fabric that has been photo-printed?

Name: Ann
Country or region: USA
Message: Will synthropal remove color from fabric that has been photo-printed?

Which kind of photo printing are you talking about? Synthrapol will not remove any properly-fixed fabric photo print.

Photographic images produced by cyanotype, also known as blueprinting, must not be washed with an ordinary phosphate-containing detergent, because the phosphate turns the blue to yellow. Synthrapol is ideal for washing blueprinted fabric, because it is free of phosphates and has a neutral pH. Any laundry detergent that is free of phosphates, soda ash, borax, or bleach is okay, though, if it is used gently and as infrequently as possible. Do not line-dry cyanotype-printed fabric outside, because sun exposure will eventually cause fading.

If you are photoprinting with light-sensitive vat dyes, such as Jacquard’s SolarFast dyes or Lumi’s Inkodyes, then washing is an important step in developing the images. After exposing the dye-painted fabric to light, you must wash away the unfixed dye with soapy water, to make the photo image appear. Jacquard actually sells a product especially designed for this purpose, called Jacquard SolarFast Wash, while Lumi is now selling a product called Inkowash, but Dharma Trading Company’s instructions for washing out Inkodyes after the light-fixing step call for Synthrapol or their generic equivalent, and the extensive instructions for Inkodyes in Suda House’s book Artistic Photographic Processes call only for warm soapy water, rather than any special detergent.

Fabric that has been sunprinted using a transparent fabric paint, rather than dye, should not be washed right away. The paint must be allowed to dry thoroughly before heat-setting, either using a hot iron or a commercial clothes dryer. (Home clothes dryers are usually not hot enough for ideal results.) After heat setting, wait at least 48 hours before washing the fabic. At that point, any laundry detergent you like will be equally appropriate.

Heat-transferred photos on fabric, produced using a product such as Avery Iron-On T-shirt transfers, can be washed with any detergent without removing the image, but abrasion must be avoided. Prints made with either iron-on transfers or any sort of fabric paint should be turned inside-out before washing, and it’s a good idea to place each item in a large mesh laundry bag of the sort used for washing delicates. This helps to protect the image from wearing off. Fabric with heat transfers should be line-dried, rather than being dried with heat.

For more information about different methods of photo-printing fabric, see my page, “How to Dye and Paint Fabric with Light“.

(Please help support this web site. Thank you.)

-Paula

Can you suggest a dye fixative for a dye bleeding problem with a black and white polyester dress?

Hello and thank you for all the helpful information you provide on your blog.

Can you suggest a dye fixative product I might try for a dye bleeding problem I have with a black and white (color-block style) polyester dress I recently purchased? Background: I bought the dress and machine washed it as specified, but ended up with the white turning gray-ish. Fortunately, I was able to exchange it and get another, but I want to “fix” the dye prior to washing to avoid the white turning to gray on the new dress. Unfortunately, I don’t know what type of dye was used to dye the fabric so I am unsure as to what fixative might work; the dress is an inexpensive dress so the dye used is likely inexpensive as well. Is Retayne a product that might work? Or Synthrapol? Something else? Also, would either product work in cold/cool water (I believe using warm/hot water is only going to exacerbate the white to gray bleeding problem)?

Thank you.

I’m afraid there is no fixative that you can use on a polyester dye.

We do know the general kind of dye that was used to dye your dress, because it is made of polyester. The only kind of dye that works on polyester is disperse dye. (See my page, Dyeing Polyester with Disperse Dyes.) Disperse dye does not bond directly to polyester, chemically; instead, it more-or-less dissolves into it.

We don’t know exactly which disperse dye was used for your dress, but we can guess that either it is a less-washfast type of disperse dye, or that some steps may have been skimped on in manufacture. Some disperse dyes are described as being high-energy, while others are medium- or low-energy. Higher-energy disperse dyes require more heat to move within the fiber, and as a result are likely to be more washfast in hot water, though they are less suitable for use as transfer dyes. Proper dye application is important, too; in commercial dyeing, loosely bound disperse dye on the surface of the polyester is removed by a process called reduction clearing. Perhaps something went wrong there. Not all disperse dyes stain when they run; some disperse dyes tend to turn into colorless compounds when they migrate out of the fiber, under the weak alkaline conditions of most laundry detergents, resulting in far less trouble with staining. None of these are factors that we can control now. They are only reasons to speculate about, when wondering why some dyed polyesters are more washfast than others, as supplied by the manufacturers.

Retatyne is a cationic dye fixative. It works by using its positive molecular charge to “glue” negatively-charged dye particles to negatively-charged textile fibers. Its best use is to make direct dye, as well as all-purpose dye (which contains direct dye), attach more permanently to cotton and other cellulose fibers. Without Retayne or another cationic dye fixative, all-purpose and direct dyes bleed badly whenever they are washed, often ruining other clothing if the colors are not washed separately, and they tend to fade quickly as a result. However, in contrast to cotton dyes, disperse dyes do not have an overall molecular charge, positive or negative, so a charged molecule like Retayne will not have any effect on them.

Synthrapol is a detergent, which means that it can help to suspend oily particles in water. It’s nice for dyeing because it is free of added dyes, perfumes, and other additives, and because it has a neutral pH. Most laundry detergents have a high pH, but, since high pH is effective in helping to fix fiber reactive dyes, and also since high pH tends to be damaging to protein fibers such as wool and silk, using a detergent with a neutral pH avoids complications. It also avoids problems in discoloring cyanotype-printed fabrics, since it is free of the phosphates that are found in many laundry detergent formulations. None of these valuable qualities of Synthrapol will make it any more useful than any other detergent at removing excess dye from your dress.

(You are right to wonder about whether Retayne or Synthrapol can be used in cold water. Both should be used in hot water. Retayne requires hot water in order to be applied, and using any detergent to wash out dye works best in hot water, since hot water is better at removing dye even without detergent. Not that it matters in this case, since neither will help, anyway.)

If you had a solid black dress, you might find that washing, especially in hot water, would be helpful at ridding it of excess dye. Black dyes of any class are more difficult to wash thoroughly enough to get all loose dye out, because more dye must be used, no matter what type of dye it is, to make a good deep black. Lighter colors are obtained with smaller amounts of dye, so there is not nearly as much excess dye to wash out. The fact that your dress is a mixture of black and white means that it is too late to try to wash out excess dye. Anything you do to remove excess dye from the black parts of your dress will endanger the white parts. The excess dye should have been removed before the dress was ever assembled.

It is possible that your new dress might have been made in a new batch, with better dye than the previous one, or with better dyeing techniques, but I would be afraid to assume so. It seems unlikely.

Perhaps you should refrain from washing the new dress at all, and have it dry-cleaned, instead. Many dyes that run in water washing will stay put in solvent cleaning. There is no guarantee that you won’t have the same problem of dye running with dry cleaning that you had with water washing, but it is something to try.

If you used warm water when you washed the first dress, whose dyes ran, then you might be okay with instead washing only in cold water. Dyes in general run more in hotter water than in cooler water, because heat reduces the property of dyes called substantivity, which is their tendency to associate with the fiber. This is why we are careful to wash less-washfast dyes only in cold water. The same dye that may be almost washed out in hot water may stay put for quite a long time if washed only in cold water.

If the dye in the second dress runs even if only dry-cleaned, or if only washed in cold water, whichever you are willing to do, then the dress is hopeless. There’s nothing else you can do at home to keep a non-washfast disperse dye application from running.

(Please help support this web site. Thank you.)

-Paula

Is it possible to reuse Procion dye vats, to reduce salt disposal?

Name: Leah
Country or region: USA
Message: I am planning on dyeing a lot of yarn (5/2, 8/2, and 10/2 warp twist cotton, in 1/2 lb hanks) a wide range of colors for weaving purposes. I’m shooting for a range of 45-60 individual shades. I’m planning on using Procion dyes, and I’m wondering if there is a way around using all the salt that would be required for 45-60 individual vats. If I am dying several shades of the same color, could I reuse the dye vat? Meaning, load the tub with water and salt, add the amount of dye needed for the color intensity I’m shooting for, add the yarn, when the dye is exhausted, remove the yarn, add dye again for a stronger intensity, add yarn, etc. Also, how would you recommend I handle adding the pH up if I do this? Any suggestions would be helpful: If I end up dumping 150ish cups of salt into my septic tank, I’ll kill it, ditto if I pour out in the garden, etc.

My first suggestion would be to use small-volume dyebaths. Dyeing with a small volume of water requires far less salt, and can even be done with no salt at all. This method of dyeing, called low water immersion dyeing, or LWI, is the easiest dye method of all, and, since it does not require salt, produces far less difficulty when it comes time for disposal. (See my page, “How to Do Low Water Immersion Dyeing“.) You can use just barely enough water to cover the material you are dyeing, and, with the smaller water volume, you do not need as much dye per pound of fiber. With such a low volume of water, salt is not required to drive the dye into the fiber to avoid wasting dye, which is its main purpose in a large-volume dyebath. In fact, the purpose of salt in LWI, when it is used at all, is to increase the complex patterning of the different colors used in one small dyebath.

However, low water immersion dying is not suitable when you want perfectly solid colors. LWI produces a mottled effect, often with a lot of color variegation. The results can be more beautiful than solid colors, but of course there are many applications which absolutely require a single solid color for each batch. For the rest of this answer, I will concentrate on high water ratio immersion dyeing for solid color dyeing, which requires twenty or twenty-five times as much water as dyeable material, by weight.

Procion dye does not exhaust on cotton the way that acid dyes exhaust on wool. After you have used a dyebath with acid dyes for wool, most of the dye will be absorbed into the wool, leaving the dyebath noticeably lighter in color. This does not happen when you are dyeing cotton. After you have used a fiber reactive dyebath, there is a lot of non-reactive hydrolyzed dye left in the water, as the result of the reaction of some of the fresh dye with the water. Depending on how long you allow for the dye reaction, and how warm your dyebath is, there will also be active dye remaining, ready to dye the next piece of yarn that gets into the dyebath.

This means that you cannot simply reuse a cotton dyebath in the way that you can reuse a wool dyebath, with relatively little effect on the color of the next dyebath. However, if reproducibility is not a high priority, with careful planning you can reuse a Procion dyebath by starting with a pale hue, then adding more dye to it to make a more intense hue that is not hurt by contamination with the first dye color, or by starting with one color and then adding increasing amounts of one or more colors to make a mixed color.

I do not recommend reusing dyebaths if your goal is to produce the exact same colors as a previous time or the next time that you dye. If your goal is only to make a great many different beautiful colors, you can reuse dyebaths, as long as you don’t find the washout of the larger amounts of unattached hydrolyzed dye that you get this way to be a problem.

After dyeing one hank of cotton and removing it to wash, some of the dye will be in the cotton, some will still be in the water but hydrolyzed so it cannot react again, and some will still be active and ready to go, to form a permanent bond to the next batch of yarn, if you use it right away. If you wait until the following day, nearly all of the dye will have hydrolyzed, by reacting with the water, so that almost none will remain to bond to the fiber in the next round of dyeing, though the hydrolyzed dye will temporarily stain the cotton. The dye reacts with the water much more quickly if the temperature of the dyebath is higher.

All or most of the hydrolyzed dye that is absorbed into the fiber can be removed by washing, since it cannot react with the cotton to form a permanent bond. The procedure is to first rinse the cotton with cool water, to remove salt, soda ash, and much of the loose dye, then to wash as many times as needed in very very hot water, to remove the rest of the unbonded dye. Synthrapol is popular among dyers for washout, and it is a good detergent for this purpose, but the real magic lies in the temperature of the wash water. Even without the chemical bonding of fiber reactive dye to fiber, the hydrolyzed dye has a tendency to associate with the fiber, by the dye property called substantivity, which is the same property that causes all-purpose dyes to attach to cotton in a far less permanent fashion than fiber reactive dyes; water at a high temperature must be used in order to decrease the substantivity of the dye, so that it will wash out. Wash water should be at least 140°F (60°C), but it works even better at nearly boiling temperatures, and it also works better if the fiber is allowed to soak in it for a while. The bond between the cotton fiber and the Procion dye is so strong that it will remain firm even if you boil the dyed yarn. It is important to remove the unattached hydrolyzed dye, because otherwise it will wash out gradually in the laundry, giving the impression of non-washfast dye, and possibly transferring the unattached dye to other pieces, especially when damp, causing unwanted dye stains. It’s a good idea to add the water softening chemical, sodium hexametaphosphate (also known as Metaphos or as Calgon T), to both your dyebath and to your wash water, to prevent hard-water minerals from forming chemical complexes with hydrolyzed dye that are particularly difficult to wash out.

After you remove the hank of yarn from the dyebath, all of the salt and soda ash will remain, except for what soaked into the yarn along with the water it was dissolved in; the concentration of both salt and soda ash will remain the same, since the volume of the dyebath will be decreased by the amount of water that the first hank of cotton takes with it when you remove it. (Squeeze the hank gently with gloved hands, or in a stainless-steel strainer with a large spoon, to remove as much of the dyebath from it as possible.) For simplicity in calculations, you could top up the dyebath with a few ounces from a fresh pre-mixed dyebath, without dye, that contains the same concentration of salt and soda ash as the first, to return the total volume to the same amount that you started with. Other than this topping up, there is no need to add more salt or soda ash when reusing a Procion dyebath. Adding more cotton to a dyebath will very slightly reduce its pH, but, since we generally use more soda ash than is strictly needed, you don’t have to worry about this at all. (Since soda ash is not a strong base like lye, we can add more than is needed without having it increase the pH hugely.)

When reusing a dyebath, you always go from a lighter color to a darker one. For example, if you want a number of different shades of blue, let’s say that you start with a 1000-gram hank of fiber (I’m choosing this weight to make the calculations simple, but just multiply each of these dye amounts by 0.227 to get the amount for 8 ounces, which is 227 grams). It is typical to double the strength of a dyebath for each increment of color intensity, when dyeing a gradation. So, for an extremely pale color, you could dye this to a 0.3% depth of shade (DOS), by using 3 grams of dye. When reusing the dyebath, you could then aim at a DOS of 0.6%, by adding 6 grams of dye (without being sure how much of the original dye remains active, which could make it darker). For the third reuse of the dyebath, you could aim for a DOS of 1.25%, by adding 12 grams of dye, then for a fourth use you could aim at a DOS of 2.5%, by adding 25 grams of dye. Finally, for a pretty dark DOS of 5%, you would add 50 grams of dye, for dyeing a 1000-gram quantity of yarn. (For dyeing eight-ounce hanks of yarn, these amounts of dye calculate out to be 0.7 grams, 1.4 grams, 2.8 grams, 5.6 grams, and 11 grams.) If you do this whole progression, you will end up with a lot of hydrolyzed dye in your used dyebath, as much as if you were preparing a single dyebath of dark black, which is sometimes used in depths of shade of up to 10%, but you will save a considerable amount of salt.

Measuring very small weights of dye, such as 0.7 grams, is tedious and requires a highly precise and expensive scale. Instead of measuring out small weights of dye, you can use stock solutions, weighing out twenty grams of dye or more, dissolving it in water, and then measure out small volumes of this. A kitchen-type scale that can reliably measure 20 grams is much less expensive than one that can reliably measure out 0.5 grams. If you make a 10% stock solution, by dissolving 20 of dye in 200 milliliters of distilled water, then measuring out 3 grams of dye is as simple as measuring 30 milliliters of the dye-water stock solution, using a plastic syringe with milliliter marks in the side (remember if necessary that 1 CC equals 1 milliliter), or a measuring pipette, or a graduated cylinder (a more accurate version of a measuring cup). Using weight in this way is the best way to measure small amounts of dye, for precision. Different batches of dye powder may be more dense and heavier per volume, or less dense and more fluffy, depending on how the manufacturing went for that particular batch, so measuring by weight, and using stock solutions for small quantities, is always the best. If you use distilled water to make your dye stock solutions, and do not let them contact any soda ash, they will stay good for weeks if refrigerated. (Place sealed dye bottles inside a closed plastic box if you temporarily use a refrigerator that is also used for foods.)

The stock solution method also makes it easier to mix dye colors. Instead of adding a certain volume of one color of stock solution, you can add half as much of each of two colors, for example turquoise plus fuchsia to make purple. To make in-between colors, it is easy to use more of one color than another; for example, you might use 20 milliliters of fuchsia plus 5 milliliters of turquoise to make a true blue. For more ideas for mixing colors, see my page, “How can I mix Procion MX dyes to get specific colors?“. Another advantage of working with stock solutions is that you don’t have to wear a respirator when measuring dye in liquid form. You should always wear a well-fitting respirator or dust mask while working with dry dye powder, to prevent allergies.

When reproducibility is not a priority, though, and if they are not preparing a large number of dyebaths, many dyers find it easier to use small measuring spoons. One teaspoon of dye equals 5 milliliters, which, depending on the dye color and dye batch, will usually contain between 2 and 5 grams of dye. Assume an average weight of 2.5 grams or dye per teaspoon, for the sake of rough conversions. Keep in mind that some colors are much more dense than others, so you can’t expect a gram of lemon yellow, say, to have as much effect in your color mixing as a gram of navy.

(Please help support this web site. Thank you.)

-Paula