"Why would a brown wash dry as a white residue?" Topic

I've been using GW's Agrax Earthshade for quite some time. I used it to shade many models in my dwarf army and have used it on other models as well.

I noticed that when I was using the past few weeks on some 40k Primaris stuff that was basecoated in Macragge Blue, that in some crevices of the models the brown color of the wash actually dried as like a dirty white color.

Thing is, it didn't happen all over the model, just in a select very few places in different types of crevices on the model. It happened in places where the model had like right angles in armor plating but also happened in places like around rivets.

I tried the wash it at different strengths, it seems to do it at both full strength and when diluted a bit.

I've been working with the same pot for quite some time. I'm wondering if at some point I didn't accidentally dip a brush in it that wasn't totally clean and I added something to the wash to make it do that. But I'm usually very careful about only dipping clean brushes into pots of paint and washes.

I bought a new bottle of which I'm going to able to start using since the old bottle is very nearly used up. I'll try the new bottle and see if it was indeed only the older stuff that was the problem.

In any event this is very strange. I'm wondering if it could possibly be some kind of reaction to the Macragge Blue spray coat? I don't see how, once sprays dry they become "inert" for lack of a better word right? I don't see how any chemical reactions could take place over a spray coat that has been dried and cured for literally several weeks.

Anybody else ever encountered this strange whitish finish when using a brown wash?

I have: but only with an old pot or when I've lathered it on too thickly.

I suggest abandoning that pot for a new one, and keeping the wash as light as possible.

Hope that helps.

yes but in my case I'm pretty sure it was because I diluted it with water from my water pot that wasn't that fresh and had had a few brushes washed out in it. The result was a milky white colour when it dried rather than a nice sepia colour.

The "freshness" of the water is really not an issue, but the degree of dilution with water is. Paints are a suspension of pigments and binder in the solvent (Water in this case). As one dilutes this mixture, at some point the pigments are too widely separated from the binder. The pigments are most often a mix of several different colors of different densities and ground to different sizes. As the solvent evaporates the different size and density of the pigment grains can make them separate form different bands of color. Neutral(Black, gray, white) pigments are often part of the mix to help make the paint opaque.

This is why it is generally wise to add more binder (acrylic media in this case) as you dilute. You need to maintain the suspension to keep the colors from separating. There are many brands of media you can get to add, but I am a big fan of Future Floor Finish, as the cost is so very low and it include a flow agent right in the mix. Future goes by many names now-a-days.
see the Complete Future:
link

A few more references:
link

link

I have had occasional problems with Agrax. The guy at the local GW store says it is absolutely essential that the pot be shaken for a long time and absolutely essential that the brush is dry.

agree with DyeHard,
I've had the same problem when I use too much water on the brush
GW makes a media (lahmia media?) that I use now to dilute
(I've also used Floquil and Reaper Media)

Thanks for this. I've had the same problem. White appearing on black hats!

@Maxshadow,

I realized that indeed the cause of it is using water to dilute the wash instead of using an acrylic medium. The moment I started using the medium the problem went away instantly.

I was using distilled water from a jug, I never use tap water when thinning paints. But even sterile, distilled water can cause that reaction with washes and inks.

As was said above in several posts, water spreads out the color molecules in a way that distorts the original color of the wash. Acrylic medium is designed to help the wash flow and remain in crevices and recesses but without distorting its color properties.

I learned a lot from this one simple problem that ended up being essentially a problem of basoc paint chemistry!