Does this happen to you?

[Bongo]

My oil paintings often glisten in spots when finished. This can last several days. Photographed they come out looking similar to what happens when you over sharpen in PS and get little bright dots all over.

At first I thought it might be the liquin medium doing it. So I made a painting without using any medium -and still got the glistening effect. On closer inspection, I found they are tiny bubbles (not in the wine, in the paint), you can actually pop them with a sharp pencil point or the like. But there are too many plus some are too small and in wet paint so popping them isn't an option. I have to wait one or two or three days before I can photograph the painting

 

[Hermes2020]

No, I have never seen that phenomenon. If, for some reason, you have to take photos soon after finishing a painting, perhaps you could invest in a polarizing filter and turn it until you find the sweet spot that has minimum reflections.

 

[AES]

That's weird. Almost sounds like a paint separation issue. Or the reverse of sinking in. What brand is the paint, and do you paint straight from the tube or premix everything?

 

[snoball]

My oil paintings often glisten in spots when finished. This can last several days. Photographed they come out looking similar to what happens when you over sharpen in PS and get little bright dots all over.

At first I thought it might be the liquin medium doing it. So I made a painting without using any medium -and still got the glistening effect. On closer inspection, I found they are tiny bubbles (not in the wine, in the paint), you can actually pop them with a sharp pencil point or the like. But there are too many plus some are too small and in wet paint so popping them isn't an option. I have to wait one or two or three days before I can photograph the painting

It is likely the fact that the paint is not sinking into the weave of the canvas. You could solve this by giving it a coat of gesso before you apply the paint.

 

[P. Barrie]

That's weird. Almost sounds like a paint separation issue. Or the reverse of sinking in. What brand is the paint, and do you paint straight from the tube or premix everything?

I agree with this possibility. Also, there may be a surface tension problem which can cause beading of paint. This happens often when glazing over a layer that is already somewhat “fat”, or possibly painting on a oil base grounding that has little or no texture/grit.

 

[Bongo]

I mix on the palette/straight out of the tube/and wet in wet depending on what I'm after. I use Lukas 1862 on gessoed panels. Barrie could be on the right track about surface tension It seems to occur mostly in areas where there are many layers of wet paint. I might trying using a hair dryer to see if that does anything. I know it won't speed up drying time since oil paint dries by oxidation, not evaporation - but the heat might expand the air in the bubbles enough for them to pop.

Aes - I tried your idea with the polarizing filter - didn't work - I think because the problem is that the bubbles are a physical object on the painting, and not stray light bouncing off the surface

 

[AES]

Aes - I tried your idea with the polarizing filter - didn't work - I think because the problem is that the bubbles are a physical object on the painting, and not stray light bouncing off the surface

lol i think you meant Hermes2020. I'm no credit thief!

I have Lukas paints too, and have not noticed any excessive oiliness, so using it straight from the tube ought to be fine. I want to do an oil soon anyway. I'm gonna see if I have the same isssue. I think the lots of wet layers is probably your answer though. As you're probably aware, some pigments are naturally "drier" than others, and all those wet layers are probably just taking their sweet time in "equalizing". And the more you agitate anything, the more bubbles you get, so...

 

[P. Barrie]

William F Martin once posted that a solution to solving surface tension was to rub the dry shiny surface with a slightly abrasive cloth prior to applying oil paint. I tried it and it worked for me.

 

[Bongo]

Breaking News -this just in!

I tried using a hair dryer and it pops the bubbles right before your eyes. But I had to use quite a bit of heat and it didn't seem to work on some of the smaller ones. The painting has been sitting for a day - it would probably work (even) better on a fresh painting.

 

[fedetony]

Just a thought: Chemical reaction producing gas? accelerated by heat?

 

[ntl]

William F Martin once posted that a solution to solving surface tension was to rub the dry shiny surface with a slightly abrasive cloth prior to applying oil paint. I tried it and it worked for me.

Long ago (before WM) I read that to remove that surface tension, rub the area with onion. I did, and do, and it works. I also read that a bit of raw potato will do the same. I've never tried it, so don't know.

 

[AES]

Just a thought: Chemical reaction producing gas? accelerated by heat?

???
Like what vinegar and baking soda does?
I do know some pigments like Prussian blue react badly with acrylic, but according to here, it's a coagulation issue, not really bubbles. And that's in wet acrylic, not dry.
Experiment time?

Edit: they don't mention the ground being used, so a theoretical oil-dry acrylic reaction may not apply.

 

[AES]

Long ago (before WM) I read that to remove that surface tension, rub the area with onion. I did, and do, and it works. I also read that a bit of raw potato will do the same. I've never tried it, so don't know.

Lol potato acid etching

 

[Bongo]

Thanks guys - but you can't rub anything on wet paint. A Chemical reaction seems doubtful to me. We are just talking about paint on paint - which is linseed oil and pigment on top of linseed oil and pigment.

Oil paint is a relatively thick substance, so I can see how air bubbles could get trapped. If you shake any liquid that is more viscous than water you are likely to get bubbles on the surface. So the act of mixing, brushing on paint could be causing the bubbles.

Also it only appears to happen where wet paint has been layered over wet paint. And when the paint has dried for a day or two there are no bubbles.

Thinking about it - mixing with a brush could be introducing more air into the paint than would a palette knife. Probably 90% of my mixing I do with a brush.

So why isn't this a common problem?

 

[Artyczar]

I'm not scientist. I truly just go by feel, but there needs to be a consistency of paint, and a "porousness" to the substraight that should be in harmony, and it sounds like this is not happening in your case. It could be one of the two, or a bit of both. The paint might not be coming out consistent, like a ratio of too much linseed oil to straight pigment. If that's not mixed together properly or well, there won't be any true binder activated in the paint you're applying on the panel.

Same with your canvas/panel/substraight. It needs a sealed tooth. In wood, it's need to be sealed, but also needs a last (light) sanding for a tooth catch for bonding purposes. Or a gesso layer if you want to paint on white, which also needs to be sanded. To clean off all the loose sand grit, use a tack cloth. Don't leave any granules. You should then be able to have consistent paint on a perfect surface to paint smoothly at that point.

This is just from my own observation/experience. Otherwise, funny things can happy. Also take pictures of the art when it's totally dry in even shade.

 

[WFMartin]

If your condition is, in fact, "beading", it seems to be manifesting itself in a way not heretofore experienced by me. I've witnessed a lot of beading, but never having presented itself in the form of bubbles, of any kind.

 

[Bongo]

Arty - all keen observations - but I'm doing all the right stuff you mentioned so it's something else.

Bill - it appears to be bubbles and will pop or recede when blasted with a hair dryer. These are very smnall bubbles. I'm starting a new painting if it happens I'll take some close-up shots and post them.

 

[P. Barrie]

What kind of solvent are you using? I’ve read that tiny bubbles can be caused by something called “solvent pop”. Google it. More a problem in commercial paint applications.

 

[Bongo]

gamsol - which is an odorless mineral spirits (oms). I also use liquin that is made out of who knows what - however in my last painting I didn't use liquin and had the same bubble problem as before.