Featured Oil/Acrylic/Pastel/Whatever: How do YOU tell?

This question comes up now and then. For instance, Johnny just posted a thread about a painting of his. I found my answer to be rambling and non-definitive, so I would greatly appreciate if some of you brainiacs would share. Since I only actually DEAL in my own art, I of course KNOW what materials I use!

How do YOU tell?

Here's how I tell, or try to.

Oils. If the artist did not prime the canvas, you can see oily patterns from the reverse. With luck, you can smell it... if you're guessing it's older than 1960s or so, and it has that oil-looking texture, I would figure it to be oil (not acrylic) even if I can't smell it. Sometimes, if you heat a hidden area with a warm-water q-tip, it revives the oil smell. Just what does oil smell like? Go sneak a sniff at an art store, if you aren't sure, or smell a few paintings you KNOW are oil. Also, oil usually seems to have a more glowing finish than acrylic. If it's cracked, it's almost certainly oil, in my mind.

Acrylics. They have a smell too. It, too, can be revived by the Q-tip thing. Since acrylics dry so quickly, there are often more layers and build up than oil, while oils lend themselves to lots of blending and shading. I'm told that a q-tip with alcohol will take up color when rubbed on acrylic, whereas oil will not.

Pastels... well... they just LOOK like pastel.

Watercolor... LOOKS like watercolors.

Gouache... can be tricky... people put different binders and stuff in, and they can fool you... ME. I guess I imagine watercolors on steroids, and that might be gouache. Sometimes, a painting (like Johnny's) completely defies me... it could be acrylic or oil or gouache, or maybe even something else!

Pen and ink... easier...

Pencil... pretty obvious.

Then there are the mixed media things... hand-tinted photographs, acrylic/oil mixed paintings... enhanced prints... more, I'm sure.

Thanks for reading, and ESPECIALLY for sharing!!!!

xo
Gila

 

Very well said!

 

Thanks, Kingsie, I got myself so confused trying to contribute to Johnny's thread I decided I needed help!

 

You're welcome!

 

Gila, I've think you've done a pretty good job of saying. I don't have any hard or fast rules. Oil and acrylic can be difficult to tell apart (at least for me). Age is a big factor. These media can show brushstrokes and texture in the pigment, and when that texture is heavy it's called impasto. But they can also be applied very smoothly, with almost no visible brushwork. They also tend to have a semi-gloss finish and are the most likely to be varnished (which can effect the appearance a lot).

To my mind, watercolors are thin and tend to be translucent, they'll show the texture of what they're painted on. They can show smooth blending, or crisp brush strokes, but the pigment won't have texture. Inkjet printing and giclees can mimic watercolor to the point where it's difficult to tell. Gouach is like a thick watercolor and more opaque. I would expect gouache to show some brushwork and texture in the pigment, but not to the extent of impasto. Watercolors and gouach have a matte finish.

Pastels have a velvety appearance and a soft look. It's not a good medium for hard, crisp lines. The pigment sheds as a fine powder at the least disturbance. Lots of blending with pastels and a very smooth, matte finish.

My opinions and I could be wrong. A lot of time you just take a best guess.

 

Thank you, MOS!
I needed that... and...
New vocabulary word. "Impasto". Using it in a sentence: The brush strokes were clear, and the paint was heavily-textured... it was impasto.
Thank you.

 

I had this small painting (assumed it was oil) that used impasto brushwork.




But then I also had this painting, which I also assumed to be oil, where, even though you could see brushstrokes, the surface was essentially smooth.

 

Mannnnn... beautiful, no matter the medium.
Maybe that's what we should focus on?
The artistic worth...?

 

I think so long as you can tell a painting from a print, you'll be alright, but with advances in technology, that becomes increasingly difficult.

Artistic merit and media are two different topics. I believe Brad has taken on the artistic merit issue more than once.

 

MOS, I thought it over and I agree.

Brad? Indeed he has ventured there, and may the Force be with him!
Hmmmmmmmmmmm... maybe time for another VeryBrad Art Challenge????

I love them.

 

I think between you two, you've summed it up pretty well. Oils and acrylics can be hard to differentiate. There are additives to both that can change the characteristics in how they go on and how they dry. In general, acrylics tend not to blend with one another when painting wet on wet. The same look can be achieved with oils if there is sufficient drying time between colors. Acrylics tend to dull fairly quickly and chalk eventually if not varnished. Oils hold their color and sheen better over time. Acrylics, in general, lend themselves to the very heavy impasto effects. I think the small painting of the house is probably acrylic. The other one could be either.

Watercolors are translucent, go on thinly, and tend to spread out in to the paper. Gouache and tempera, while also watercolor, are thicker and tend to stay put when painted. These three are used almost exclusively on paper. Seldom do you see oils used on paper but you will occasionally see acrylics.

Modern works tend to be done in acrylics, though many artists still use oils. I am not sure when acrylics became widely available but truly old works on canvas or board are, of course, oils. While it is nice to know what you have, I am not so sure that it is all that important otherwise. The medium tends to be secondary to the merit of the work.

 

Thanks Gila, I'm often scratching my head when trying to fill in Ebay item specifics, is it oil or acrylic?

Still not sure I can tell the difference though!

 

Good idea for a thread, Gila! I like learning things here.

 

Thanks, everybody!
I'm gonna put this thread in my Favorites so I can give it to people with this sort of question in the future.

 

Great thread Gila! I know I learned a lot here. Thanks for sharing.

 

A GREAT thread to KEEP!!!! NICELY DONE all contributors!!!!! And THAT, my friends, is why this place is SO GREAT!!!!!

 

WORD, y'all!

Thanks!
Don't ya just love us?
I do.
xo
Gila