I'm going to try my first pin wash. I'll spray a model with a Vellejo acrylic glossy coat and apply a wash. I was thinking about using a watercolor wash. However, several posts indicate that an oil wash is more forgiving and essentially fool-proof, compared to other methods.

Can anyone tell me why?

Oils (and enamels to a lesser extent) have very long drying times. Meaning... if you don't like it, you can wipe it off, minutes or even hours after you've applied it.

Acrylics will set up a lot quicker, and become permanent much faster.

If I may... I would suggest wetting the area you're working on first with thinner. Just get some fluid on there. Then add your wash color, and work it into the recesses and details. You want to avoid tide marks, which is why you wet the surface to begin with.

Water colors have a lot of surface tension, meaning they want to bubble up and not spray out. They tend to give very uneven finishes in my experience.

I got it. I assume that a turp won't damage a completely dried acrylic paint (in my case the Vallejo glossy coat).

Well, the last time I used oil paints was 1982 when I was a high school kid!

Chris read thru the painting and weathering sequence in the painting forum it will explain a lot and answer almost all in not all questions. Cheers.

Nothing's fool-proof, not even artist oil washes.

Having said that, though, Jesse's advice is good, and the long-working time is the characteristic that is so forgiving.

Still, you have do have to put some effort into it to avoid tide marks and some practice is in order to achieve the desired effects.

To Jesse's advice, I'd add to work in a small area first to get the hang of it and use a brush dampened with mineral spirits to clean up any tide marks that start to develope as your washes start to dry. These are the "shiny" rings that can form around the washed area like ragged circles.

Tide marks are caused by a combination of capillary action, surface tension, and the binders in the paint (in this case the sun flower or linseed oils). As the wash spreads out (capillary action), surface tension will cause a "hump" of liquid on the outter edges of the wetted area. The middle of the area will just barely be wet, and the center where capillary action and surface tension makes the wash pool around details will also contain more liquid.

Your washed area will usually dry starting in the middle portions between the outter edges and the center pooled areas. Generally, the pigments in the paint will gather in the pooled area (although some will flow towards the "humped" edges). Also, thinned paint, because of its volume on its edges will contain extra binders (oils here).

What all this means is that as the wash dries, the pooled areas around details will get dark from the pigments. The middle areas will dry first without any (or very little) pigments or binders leaving the center pools and an outter ring to dry last. As this outter ring (where the "humped" edges with the excess liquid had formed) dries, it will dry from its outter and inner edges towards its center. This draws the binders and pigments into an ever smaller ring-shaped area and when fully dry leaves behind the "tide mark."

If you catch these "tide marks" as they form or before they dry hard, you can wipe them away with a clean brush slightly damp with thinners (mineral spirits). Sometimes, if all you have are shiny rings from the binders, a clear flat coat will make the tide marks vanish. However, if there was an amount of pigment along with the binders, then a flat coat just leaves darkened rings behind. This depends on how heavy / dark you mixed the wash to start with. The darker the wash, the more pigment there will be in the outter "tide mark" areas.

The reason for all this explanation is that if you understand what's going on with your washes as they dry, and how the tide marks are formed, then you can figure out what to do about them.

Here lies the beauty of using oils for your washes. Once the wash appears dry, and you can see the tide marks (if any have formed), the wash is still not really "dry." The long working time will allow you to go back and wipe the marks away before the dry hard.

Acrylic and enamel paints, when thinned as washes, act exactly the same way, in so far as capillary action, surfance tension, binder and pigment concentrations, and sequence of drying. However, unlike oils, once the binders in the the acrylics or enamels have "set," you're pretty much stuck with the results.

Sometimes enamels will "reactivate" with fresh thinners - but acrylics are permanent once dried. Most inks are also permanent once dried, so proprietary "figure" washes and inks, like used for painting war-gaming miniatures, are just like using acrylics for washes. (They can be used, just with some care and experience.)

And just in case you're wondering, normal artist water colors don't have any strong binders in them, so tide marks can be wiped away with a brush damp with ordinary water. Their drawback, as mentioned by Jesse, is that ordinary water has relatively high surface tension which prevents water color paints from flowing and behaving like other washes.

Oh well, I know this was kind of long-winded, but "Give a man a fish and feed him for a day; teach a man to fish and feed him for his life..."

HTH,

Yes, that's it

Furthermore oil colors tend to be more "transparent" than the acrylic ones so you can achieve finer effects. Anyway you should also use a bit of water based colors to render some located dirty stains on your model

cheers

Thanks everyone. My primary job is to do research. So, I tend to get every single piece of information before doing something. I've read so many articles about washing (including the sticky at this forum) and want to know more. I guess I'll just have to do it and see what happens.

Well, I made up a little sketch to show what's going on and how the tide marks form.



The reason why pre-wetting the area with clean thinners helps to prevent the tide marks is that it encourages the wash to spread out furthur without forming the miniscus around its edges.

Anyways... This shows how tide marks form.

Wow, a picture is worth a thousand words!

I was going to ask the same question. I normally use water-colors for my washes. Copied all of this for my next wash.