Dyeing or painting furniture fabrics can be a challenge at best, and a risky endeavor at worst. It's vital that you choose the appropriate options for treating your furniture so you get the result you want, and so your new fabric color is pleasing as well as durable and lasting.
Your best and safest bet when dyeing furniture fabric is--if possible--to remove the fabric from the furniture in order to dye it. This will enable you to use traditional high-end fabric dyes that can be rinsed, and ensure that you create an even and long-lasting new color for your furniture. While this is easy to do with a simple chair seat covering, couch cover, or slipcover, it's not always possible to remove the fabric covering your furniture, leaving you with the option of slipcovering, or of dyeing the fabric without removing it. In this case, your best option is either a spray dye or a fabric paint, either of which is applicable to the furniture without removal of the fabric, and each of which offers its own pros and cons.
Before you dye your fabric, whether you're using a traditional cloth dye, spray dye, or fabric paint, you'll need to test the application on your fabric in a spot that can't be seen, to ensure that the dye will work the way you expect. Follow the application instructions, and make sure your fabric readily and evenly absorbs the paint or dye. For fabric dye, it's vital you ensure that your dye rinses well, and that your fabric does not shrink, so test for shrinkage beforehand wherever possible.
For the best paint or dye for your particular furniture fabric or upholstery, consult your local DIY store to ensure you make the best possible choice for your fabric and texture. Fabric paints can be sprayed, brushed, or airbrushed on a wide variety of fabrics. If you choose to spray paint your fabric, make sure to do so in a large, well-ventilated area (outside is your best option). Spray paints give more even coverage than dyes, and can be "set" through the use of a heat setter or heatless spray fixative. Make sure you let the piece dry for at least 5 to 6 days--a week is even better. Another alternative is airbrushed ink, which works well, covers evenly, and allows you to achieve a deeper, richer tone. However, ink can run--get expert advice before using ink, so you know the risks as well as rewards, and can minimize the chance it will run or stain in the future. Brushing your fabric by hand is another possibility, but it's often your least attractive option, because it is very difficult to achieve even coverage brushing by hand, while airbrushing or spraying results in more even coverage and texture. However, another surprisingly effective technique for dyeing your fabric is to use sponge painting instead of spray painting or airbrushing. The effect is softer, and it's best to sponge paint something with a color meant to be shimmery and uneven.
Safeguarding Your Dyed Fabrics
Pay close attention to whether your dye or paint choice will require simple air-drying, heat setting, or fixative to safeguard the color process, and choose the proper finishing element accordingly. Test liberally at each step of the process to ensure that your application is covering evenly and absorbing as expected, and never take shortcuts where the drying or setting process is concerned.
Ultimately, fabric paints or spray dyes are not your best bet, because you are always essentially applying a layer of color to the outside, and the risk is that this layer can be rubbed off over time by repeated contact with the furniture. Never dye anything you aren't prepared to lose. Fabric paints, while occasionally extremely workable and effective, can also end up uneven in the outcome. Testing first is vital. Keep in mind that if your fabric or upholstery is "stain-resistant," this will also make it resistant to dyeing or painting. Don't forget to wear a mask when spraying or airbrushing, to ensure that you don't breathe in the paint or dye droplets, fixative, or other elements.