I love bright colours. Decided I needed some for the quilt I'm currently making, so had another dyeing session yesterday. People have asked me how I get such bright colours: here's my basic method for dyeing brights.
1. First of all I use urea. It makes the dyes more soluble in water and enables the dye to dissolve more easily. It has other qualities too - it keeps fabric wet for longer (important when dye-painting silk for example) and if you dilute dyes with it it helps to get even-coloured pales and pastels. It even makes fuchsia behave! I would not be without it. So I begin by mixing a urea solution - nine tablespoons full to two litres of very hot water. Quantities are not critical - if you have some urea pearls left undissolved at the bottom of the jug they'll keep.
2. I immediately put my dye-powders into containers - for strong colours I put in 2-4 teaspoons per cup depending on the dye: light dyes (more bulk per gramme) such as turquoise, rust or gold need more, heavy ones like fuchsia need less. Then add a little urea mix (also called chemical water) and a plastic spoon to each container and stir well - the ideal is a smooth paste. Then add about a cup full of chemical water. Go away and have a cup of coffee, prepare your fabric if you haven't already done so but leave the mixes time to dissolve. If you're not sure, stir - if there's anything solid on the spoon it means the dye is not thoroughly dissolved so stir and leave some more (you can also strain through an old pair of tights to remove undissolved dye but I've never had to do that yet). The advantage of working with dye solutions rather than with powders are firstly that it makes the whole process safer (you spend less time risking inhaling the powders) and secondly it gives you easier control over shading the colours.
3. Mix up the soda ash solution: approx 8 tablespoons per two-litre jug. I have been known to use guesswork here and not have problems. MAKE SURE YOU LABEL THE TWO JUGSFUL OF SOLUTIONS SO YOU KNOW WHICH IS WHICH.
The urea and soda solutions keep for ages. The dissolved dyes should be used quickly as otherwise they bond with the water. They will keep longer in cool or cold conditions - a day or so (longer if you have a spare unused fridge you can store them in); in hot weather use within a few hours. If you have dye left over at the end of a session be adventurous - use it up by trying different colour combinations, dyeing different items - revitalise those dingy white knickers socks and teeshirts. Whatever.
4. Prepare fabric: non-PFD (Prepared for Dyeing) fabric (also called loomstate) often has dressing in it which needs to be removed or the fabric can't take up the dye: scour in hot water plus detergent; you can also improve matters by adding a handful of soda to the wash water. You can do this bit in the washing-machine but leave out the soda. Rinse thoroughly (in the machine is fine). If you rinse by hand, adding a tiny drop of baby shampoo or washing-up liquid to the final rinse will help the dye to penetrate difficult fibres such as wadding (batting in the US). I also tend to rinse out PFD fabrics in hot water before using as this seems to enable them to absorb dye more readily.
5. Add dye to fabric: in a separate container add the same amounts of dye and soda solutions (the dye solution can be diluted with water/chemical water). Pour/dribble/spray this onto the fabric. Use a second colour and repeat the process. And so on until you are happy with the result (remember it dries paler). If you are using strongly contrasting colours avoid overloading the fabric with dye unless you really like shades of mud!
6. Leave the dyes to do their work - preferably at a warm temperature overnight if you can wait that long. It's possible to leave them for too short a time but you're unlikely to leave them too long (I once found some dyeing fabric shoved into an invisible corner that had been sitting there for a couple of weeks and it was fine though I wouldn't want to risk it with silk which rots more easily). Then rinse, first in cold water to remove the soda ash, then in hot to remove excess dye.
Then wash in really hot water and detergent (the milder kind without added whiteners which could bleach your fabric slightly). I usually leave the fabric to steep in the soapy water for ten minutes or so - this makes it easier to remove the excess dye. I then rinse in hot water and steep in hot water for a further ten minutes before flinging it into the machine for a full rinse cycle.
I am not the kind of dyer (and there are many of them) who thinks her method is the only one that works. It is simply the method I learnt with, have continued to use and which works for me. If you're a beginner dyer do try other methods; you will eventually acquire a range of techniques that work for you!