What do you put in your oil painting after you're done painting it?

Varnish, and yes you put it on your paintings. Always.
I use it no matter what kind of paint I’ve been working in.

It’s used to protect the paints, give it a ‘finished’ look at the end, it seals it to a certain degree from the elements, and makes the colors POP. Seriously, the second you varnish a painting the colors brighten and intensify as you do it, it’s pretty cool to watch. Overall it’s kind of like when people buy iPod cases. Why do they do it? Sometimes it can add protection and a specific look. Same reason you varnish or seal a wooden deck, seals out water, makes the wood last longer and makes it looks good.

You should always use the correct type of varnish for your piece depending on what you used in it. It’s not that difficult, the can tells you all you need to know like what you can use it on and when you can when you buy it.

And always, and I mean always wait 12-24+ hours to varnish.

Sometimes, you can get away with sooner, but that’s something you figure out with experience and getting to know your paints, but it’s risky and very often you can end up destroying your work because you didn’t wait a day.

My last painting was my final for an art class, I varnished it after about six hours, cause it seemed dry and the class was in a few hours. And all the blacks bled out over the painting. I had to work like you wouldn’t believe to finish it.

I almost cried.

… sometimes you need to wait longer than 24 hours. Depends on how goopy the paint buildup is. If you have big fat Van Goghesque swirls, oil paint can take months to dry,
because under the dry-feeling skin on the surface, it will still be gooey underneath for
some time. Oil paint doesn’t dry by evaporation (which is quicker) but by… some other chemical process that takes much longer – the oil molecules have to bond.

But yes, varnishing is great. It does make the painting more vivid and it protects the surface.

You can also add some stuff to your paint as you paint called Japan Drier (or Dryer). It
makes oil paint clinch up faster (my word for the process I can’t remember the name of).
This does mean you have to work faster.

If you decide to have a go with acrylics, which are water-based and therefore dry easily within 24 hours even if very thick, you use a water-based varnish if you like, though it won’t make such a dramatic difference; this can be bought where you buy the paint. Don’t use an oil-based varnish. Also, don’t use a water-based varnish with oil paintings.

A useful principle to remember with oil painting is “fat over lean”. You’re probably thinning your paint (if at all) with a mixture of linseed oil and turpentine. The turpentine dilutes the amount of oil in your mixed paint,making it “leaner”. If you apply a “fat” (less turpentiney) layer of paint over a “lean” layer, all will be well. But if you put a “lean” layer over a superficially “fat” layer, the lean layer will dry before the fat layer has time to do so, and eventually the lean layer will wrinkle and crack as the paint under it contracts.

When I used to paint back in the early 90’s, I’d varnish my work sometimes months afterwards. Seems certain types of oil paint take FOREVER to dry, especially since I was a heavy handed painter. Best thing to do is set it where dirt is less likely to settle on the paint, in other words protect the newly painted surface, and check the places that are drying the slowest every couple days or so until it is dry enough to cover with a protective coat. Sometimes using cheap varnish is worse than not using any at all.

In in doubt, waste some paint and varnish on canvas just to test. Better than ruining your work.

On the wall?

Oil paints need a varnish.

@frankielaguna: The question doesn’t say ‘where do you put an oil painting’.

@susanc: I absolutely disagree with your statement that varnish on acrylics won’t make a dramatic difference. That has not been my experience at all.

I wait a year to add the final varnish. In the interim I add a thin coat of Galkyd Lite by Gamblin. This makes the colors pop and gives a mild sheen.

The varnish I recommend and use is Soluvar by liquitex- it is non- yellowing and can be removed for restoration a few hundred years down the line.

I would also like to add that I prefer brushing on the varnish because I have found that sprays will blow any airborne contaminants onto the painting to embed in the varnish.

This includes pet hair and dust.

thanks to all, very helpful answers. aside from Soluvar/Liquitex mentioned by Dog, what other brand names of varnish do you use for your oil paintings? which you consider the best. for comparison purposes.

I use Soluvar too!
Art high five.

But, I do spray it on, as I have never had a major problem, save a piece of pollen that I can easily dab off with my finger, spritz again and bang you’re done. I also suck at making an even coat of varnish when I paint it on.

I am also lazy.