Q) I'm still early into my apprenticeship although I am pleased with my progress, im am still looking for a really light gray wash, i want to use a really light gray and get more values into my tattoos.
Could you advise me what gray systems you use and what you mix them with?
A) The answer is deceptively simple- use more water! The more diluted the ink, the lighter the gray. Simple as that.
A number of pigment manufacturers are now marketing graywash kits with a range of dilutions... Silverback was one of the first on the scene. I know that Eternal (whose pigments I use for about 75% of my tattooing) also has a graywash kit. You may enjoy using these kits, as they provide several degrees of dilution and because they are prebottled, you'll get predictable results each time. When you pour your palette, make a gradient arrangement: undiluted black on the far left, next to it the strongest mix, next to that the medium strength mix, etc. and you'll have a basic idea of where to dip your tube for each strength. Without putting them in order like this, you'll have a hard time knowing which is which, as they all look the same in the cap.
But the answer isn't all in using these kits. Personally, I make all my own washes by simply putting a few drops of black in the bottom of each cap and filling the rest of the way with water. I'll pour an undiluted black, then a half cap of black, then a quarter cap next to that, then a cap with only a couple drops in it... the I fill the partial caps the rest of the way with water. So far, not much different from using the kit. I also keep a rinse cup handy that I won't be using for rinsing color or white- just for diluting black. Then, by dipping back and forth between the various different mixes and the water cup, all strengths of graywash are theoretically available... it's just a matter of developing a touch for it.
One thing that's conspicuously absent from all of the graywash kits is a truly dilute wash- an extremely low percentage of pigment. Most folks just don't see the use for these 3-5% mixes, but a lot of the smoothness you see in really good graywash work comes from using them. Mostly you can get these dilutions just by dipping into a light wash mix and then into the rinse cup. In a good black and gray portrait, for example, only a small area- if any- of the portrait will be truly untattooed skin- a lot of the subtle value range you see in the cheeks and forehead come not from using a medium wash with quick brushstrokes, but from a thorough working with extremely light washes. The highly diluted washes allow you to work the skin a bit more, getting things smoother, without going too dark
For the best overall look, you need to aim to use the whole range of values fluently, with gradients starting at the black end of the range, a good sampling of mid-range values and plenty at the very light end, plus everything in between. Some of the weakest looking graywash tattooing comes from artists relying too much on one bottle of wash, and not exploring the whole range.
As with many of these topics, though, it's not all about technique- there's a drawing skill component here as well that can't be ignored. If you can't get a smoothly shaded look with pencil on paper, you'll have a real struggle achieving it on skin. You really need to log a lot of hours on paper to get the best look with your shading- and using the various softnesses of pencil (HB, 2H, 4B, etc.) you can practice using the different values of wash... obviously there are a lot of differences between paper and skin, but the thought process that goes into the shading is as important, if not more important, than the pigments and techniques you use. The concept behind how shading works is far more crucial than any of these relatively minor technical details... with a good idea in your head of how to shade, you can easily get by with a cap of black, a rinse cup and lots of dipping between them. So, not to sound like a broken record or anything: The better you can draw, the better you'll be able to tattoo. Good drawing skills are the crucial advantage in any style of tattooing.