dry brushing - scientific explaination?

[usurpator]

Sometimes when I drybrush (I rarely do it these days but I\'m painting 250 dwarfs so for the beards....) I get a clean result, sometimes a very powdery one.
In both cases I have taken all the paint out of the brush in the same way.
BUT I\'ve noticed that many times the dust effect happens when I use a brush that was in water during the past hours - of course I dry it thouroughly before using it, but it seems some dampness remains.
Can anyone confirm this of give a scientific explanation?

 

[usurpator]

or can anyone tell me why the chalk effect appears?

 

[Talion]

It maybe because the brush is damp and clumpping together on the wet bristles before it gets applied, so you\'re kinda brushing on larger particals.

I don\'t actually know, but that\'s what i guess.

When drybrushing things like beards, I then add a watered down virtually inky layer of the drybrushing colour, this helps with bringing the shaded area and drybrushing together. Then add final highlights painted on.

 

[usurpator]

ooooh that inky idea is great!!! many thanks!!!:beer::beer:

 

[Tinweasel]

I\'m no scientist, but if I had to make a guess, maybe the remaining dampness of the brush comes off along with your paint and evaporates, causing the drybrushed paint to dry quicker than it normally would and thus turn \"firm\" and \"chalky\" instead of settling and conforming to the figure slightly as it normally would during the natural drying process.

The only thing I could compare this to mentally, is when you\'re spray priming in slightly humid air and you end up with an \"orange peel\" effect due to the combination of primer + water particles in the air and on the figure. Alternately, spray priming from too far away so the primer dries in mid-air and you end up with already-dried primer particles stuck to your figure.


As mentioned above, if you put an ultra-thin wash of any color over the top of drybrushed surface it\'ll smooth out the graininess a bit - you could maybe even drybrush a shade lighter than what you intend for the final finish (like a slightly brighter highlight color) and then use a shading wash to both shade and take the edge off the drybrushing at the same time... Likewise, if you seal with a layer of gloss prior to sealing with matte varnish, the gloss will smooth out the surface while the matte causes things to \"blur\" slightly due to refraction.

 

[usurpator]

It makes sense!!!
I\'ve painted several beardes today and found out another thing: it seems that when the brush is vaguely wet or seems dry but might not be some paint goes up higher in the bristles. When I wipe the brush I only wipe the tip... and if I press too much = chalk from the upper regions (gosh, this last expression sounds like the title of a movie with Doug McClure!!!:drool::drool: arg)
do I make any sense at all???

 

[supervike]

It makes very good sense.

So in essence...to use drybrushing without chalkiness, one has to have a completely dry (not just dry looking) paint brush to start with?

Interesting.

Hi, I\'m Doug McClure, and you may remember me from such films as \"Bill, the friendly Carcigen\" and \"Chalk From the Upper Regions\"

 

[Tinweasel]

One other suggestion, I guess, in terms of tips learned through trial and error - if you drybrush and your paint source is already thinned slightly, you\'ll end up applying less color overall than if you just use straight paint. (It might cut down on the chalky effect?)

I don\'t know if this\'d help you one way or the other trying to get color onto dwarf beards, but I guess it might if you\'re going for subtle coloration changes.

 

[usurpator]

Originally posted by Tinweasel
One other suggestion, I guess, in terms of tips learned through trial and error - if you drybrush and your paint source is already thinned slightly, you\'ll end up applying less color overall than if you just use straight paint. (It might cut down on the chalky effect?)

I don\'t know if this\'d help you one way or the other trying to get color onto dwarf beards, but I guess it might if you\'re going for subtle coloration changes.

BUT that introduces some water in the brush... chalk effect again?
Doug McClure stars in: \"Dwarf-polisher versus Mr. Surfacer\"

 

[Tinweasel]

BUT that introduces some water in the brush... chalk effect again?

Guess it depends how you get paint onto your brush? I usually have mine on a separate palette where I add thinner and mix colors. I don\'t dip my brush into the pot at all, and when I wipe paint off to drybrush, it\'s usually pinched between paper towel to wick as much moisture and paint off as possible. (Then again, I also use dry time extender and a flow improver in my paint thinner mixture, so that might avoid the \"chalky\" look, too.)

 

[Trevor]

I\'m no scientist, but if I had to make a guess, maybe the remaining dampness of the brush comes off along with your paint and evaporates, causing the drybrushed paint to dry quicker than it normally would and thus turn \"firm\" and \"chalky\" instead of settling and conforming to the figure slightly as it normally would during the natural drying process.

I am a scientist, that sounds backwards, if there is more water the paint will take longer to dry.

I add water to the paint to thin it to drybrush to make it smoother.

I can\'t think of any good scientific reason why a wet brush would make the paint chalky.

 

[misterjustin]

I remember reading somewhere, ages and ages ago, that a damp brush will give you exactly the drubrushing results you\'re talking about.

I had the problem myself so I went out and picked up a pile of super cheap square head brushes. Now I use a different brush for each drubrushing -- until each one is completely dry.

I haven\'t had the problem since I started doing it this way.

Where\'s the science? I have posited a solution -- see if you can replicate it

 

[Trevor]

Of course I have been known to be wrong...

 

[usurpator]

Originally posted by misterjustin
I remember reading somewhere, ages and ages ago, that a damp brush will give you exactly the drubrushing results you\'re talking about.

I had the problem myself so I went out and picked up a pile of super cheap square head brushes. Now I use a different brush for each drubrushing -- until each one is completely dry.

I haven\'t had the problem since I started doing it this way.

Where\'s the science? I have posited a solution -- see if you can replicate it

Yes it works! I keep dry brushes for drybrushing (silly formula??) but it means not washing the brush at any stage which kills the brush even faster

 

[usurpator]

Originally posted by jondalar
Adding water to acryllic paint causes it to dry quicker. Try putting a blob of undiluted paint next to diluted paint and watch what happens!

this is counterintuitive!!!!!
arrrgh:cussing: and it\'s true toooooo!

 

[Einion]

I don\'t do drybrushing much any more but in the past when I used it more regularly I found the results were always better with what all the basic painting guides say to use: a totally-dry brush.

Just off the top of my head I thought that the powdery look would be more common the normal way ???

Experimenting over the years with thinner paint or a brush that was very slightly damp I got different results (not worse though, just different) and I don\'t remember that I got a powdery results at all this way, since in fact what you\'re doing is more akin to scumbling rather than drybrushing which is a \'smoother\' technique. Maybe the paint type is important here?

Originally posted by jondalar
Adding water to acryllic paint causes it to dry quicker. Try putting a blob of undiluted paint next to diluted paint and watch what happens!

This is a bit misleading, although it can be technically accurate (varies a bit with diff. paints).

Adding water to paint and you get thinner paint. Thinner paint goes on more thinly, and hence tends to dry faster than thicker (more viscous) paint.

To really look at this you have to compare equal volumes of paint, with the same surface area

Einion

 

[EArkham]

You guys seem to be getting the exact opposite effect I get.

When I want dusty, powdery, & chalky, I make sure the brush is dry as possible, going so far as to not even rinsing the brush off before using the next drybrush colour (especially for rocks and weathering). When I want something smoother, I make sure the brush is moist.

Bizarre.

Kep

 

[Rodnik]

Yep..I\'m with Kep on this one.
If I want powdery---I keep my brush extra-dry.
If I want smooth, I make sure the brush is moist (and ultimately use a \"wet-brush\" technique).

As odd as it sounds--I suspect your powdery result is *not* from leaving it in water for an hour, but rather the fact that you dry it off thoroughly when you remove it from the water-----probably using a paper towel to do it, with a slight \"pinching\" of the bristles between your fingers.
Which, ironically enough, is exactly how I achieve a powder effect with a drybrush (for stone, as Kep was saying).

When I want smooth---I dampen the brush, and don\'t use a paper towel to dry it--rather, I just wick off the moisture on the side of my palette, so as to not get a \"paint bomb\".
I then use the side of my brush to get a good, smooth, texture ( I do hair this way, for instance).

Kev