Just like prepping and priming your models, when hobbyists and mini gamers first start to paint miniatures, one of the largest mistakes they make is not thinning paints. Acrylic paints, the most common of all the hobby paints and the ones readily available from your game company of choice, are nothing more than a pigment suspension in acrylic polymer emulsion. Basically, they are colored pigment mixed into a medium. Depending on the company and the color, the consistency can range from a milky thin liquid to a gelatinous glob of paint. While you can save a lot of time by applying paint directly from the pot, you can take steps to improve the quaility of your paint job with a relatively easy process. Regardless of where you get your paint from, thinning your paint is a good idea for many reasons when painting miniatures.
The first reason is that non thinned paint can wind up chalky and showing brush strokes. While this can be a good effect that you can use on miniatures sometimes, it shouldn’t be how it is all the time. Lighter colors, such as white and yellow, tend to suffer from the chalky effect, and it can ruin the color and make it even harder to make the color achieve proper coverage. This also occurs as the paint dries while using it. Thinning your paint also provides an additional amount of liquid to keep the paint, for lack of a better word, lubricated while you use it to keep it from drying out longer. While some may balk at that concept, keeping your paint as pliable as possible is important as it allows you to maintain control of the paint longer. This helps to produce better lines on your models as well as ensure that you keep the paint where you want it to be. I know that it can seem counterintuitive that the thinned down paint would stay where you want it to go easier than thicker paint, but that’s part of why you primed your miniature to have nearly sandpaper texture before. Thinned paints apply smooth even coats of paint, resists brush strokes and can be used to define detail, where unthinned pains tend to obscure details. This is particularly evident on things like faces on miniatures. Think of using unthinned paints like those overly done makeup effects in movies where the actor looks more cartoon than human.
The second reason to thin your paints is to assist with layering and blending your colors. One of the goals of a miniature painter is to simulate real life color effects. While you are working with real life miniatures and paints, at the scale in which we model natural highlighting and shading are extraordinarily difficult to see with the naked eye. Because of this issue of scale, we simulate this through layering of colors, highlights and shades. To make color transitions look more natural, you want to gradually build color up from the base coats to the highlights, and this usually means multiple layers of colors. This lets you slowly build your colors from darkest to the brightest and makes the transition between colors look that much smoother and more natural. Non thinned paints can be used, but it makes things like highlights and shading look much starker in contrast to your base colors than it would be otherwise, and tends to be a bit more difficult as the thicker the paint, the less of the previous color or underlayer you are going to see which can create artificial breaks or lines in the color to the eye. Third, thinning your paints allows you get a longer life-span out of the paints you use. Most paints designed specifically for miniatures will run you anywhere between $2 and $10 USD for a rather small bottle or pot of paint. Sometimes colors get discontinued or formulas change, and if you run out of a certain shade you may be hard-pressed to find a match. By thinning your paints you will need to use less over the course of each miniature to achieve coverage and complete your painting tasks. This is probably the most minor of the benefits, but one that will have appreciable impact over time.
At the most basic level, you will need a thinning agent. Something to dilute the paint and change the viscosity. There are several ways to do this, and if I’ve learned anything in my time as a commission painter it’s that everyone has their preferred method and each one is hotly debated. One thing remains the same, though, and that is the desired consistency of your paint. Almost all painters who thin their paints are of the mind that you want the paint mixture to be roughly the same consistency as 2% milk. This allows it to be thin enough to properly blend, and allows it to flow evenly and nicely off of your brushes onto the model without clinging to the bristles and allows you to have a good amount of control over your paint.
The easiest way to thin your paints is with good old-fashioned water. Acrylic paint is a water based medium, so you can simply add more water to this mixture to increase the fluidity of the mixture to the desired consistency. You can use tap water, which is by far your cheapest option, but additives and minerals in the water can alter the paint or affect drying time, so at the very least i would recommend filtering the tap water if at all possible. A cheap but effective option as well is distilled water. You can pick this up at any local grocery store or pharmacy and will only run you a dollar or two for a gallon which will last you for a long time. Now, acrylic paint as we said earlier is pigment suspended in a liquid, in water pigment tends to settle to the bottom of the mixture, and this will manifest itself if your mixture has too much water. While it is a great place to start with learning how to thin your paints, it is something to be aware of. I have heard of painters using Windex or other glass cleaners as well as glossy floor finishes mixed with water as thinning mediums, but they can be tricky and depending on the chemicals in the actual cleaner or polish will have variable drying time and will require some experimentation to get right.
There are also a number of commercial thinning mediums available as well, and most miniature companies who offer a paint line of any type often have one available, the only downside is that these can be quite pricey at times for not a lot of product. A bottle from Vallejo for example can run you anywhere from $5 USD to $20 USD for a small bottle of only 17 millilitres. Another option available is the use of extenders, otherwise known as retarders, that increase the working time of acrylic paints by extending the drying time while diluting the mixture. Professional art supply stores and even your local hobby shop can carry these from companies such as Liquitex, Winsor and Newton or Golden. These same companies also make airbrush flow aid mediums which can be used as a thinning agent as well. They can be quite pricey at times, but smaller bottles as well as items on sale and coupons can help you save some money. You are going to want to experiment to find what works best for you and your miniature painting.
While I’m on the topic, I would like to take a few moments to share with you the mixture I use on a daily basis. I picked up the recipe a while ago from another commission painter, and it is the best I’ve found in ensuring easy mixture and flow of paint as well as extending drying time while keeping the colors of your paints bright.
Here’s the recipe for your enjoyment:
40% Drying Retarder
50% Distilled Water
10% Flow Aid / Airbrush medium
What I do is pick up a 10oz squeeze bottle from Sally’s (or another, regional beauty supply store.) It comes pre marked in ounces, which makes it much easier to measure out. If you can’t find a bottle with measurements on the side, that’s quite alright. Get yourself a bottle of slow dri or another drying retarder, I perfer Liquitex Slow Dri which comes in a handy 4oz bottle, and a gallon of Distilled water from a grocery store or drug store. This small sized bottle of Slow Dri can be picked up at a local art supply store for under $10 USD. Throw the slow dri in the 10oz bottle, then if your destination container doesn’t have measurements, fill the now empty bottle to almost the top with distilled water and then pour that into the 10oz bottle. Fill the rest of the 10oz bottle with flow aid or airbrush medium and you then have yourself a thinning medium that not only will last you a long time, but will increase your paint working time and improve your time as a miniature painter.
The benefit of this mixture is that it will thin your paint while helping to suspend the pigments, increase drying time and normally winds up being cheaper than most stand alone thinning mediums. it also makes mixing easier as mixing it in a 2 to 1 ratio of paint to medium comes out to the perfect consistency. I have painted a few hundred miniatures since the last time I made a batch of this and I’m only barely halfway through the bottle.
Whichever method you use, I highly recommend thinning your paints, even if they claim to be pre thinned or airbrush ready. Your miniatures will come out looking much better and you’ll have a far easier time painting your miniatures.