What is varnish and how do you apply it to an oil painting?
Varnish is the final layer you apply to a dry oil painting to protect it and add a glossy finish. To apply the varnish use a large sturdy brush. In the vertical direction of the painting brush on the varnish in long straight lines. Apply as long of strokes as you can, ideally covering all the way from the top to the bottom of the canvas. This will ensure that your painting maintains a ‘wet’ appearing finish.
What is varnish?
The main ingredient in any varnish is resin. This is what gives it the clear glossy finish it is so well known for.
Why use varnish?
First and foremost varnish protects your painting from things like dust, debris, or even spilled paint. It creates a sealing layer that can be removed in the future to clean away any dirt that builds up on the exterior.
More Importantly The ‘Wet’ Look
Varnish helps to give a painting a ‘wet’ or glossy finish. All oil paintings become somewhat dull by the time they are fully dried. As a painter this can be somewhat frustrating because even an area that you painted last night may look more dull in appearance today. A short term solution to this problem is to 'oil out.' While a great temporary solution, you can not keep oiling out a painting for the rest of its life! The way to solve this problem for the long term is to use varnish. It will make the paint look like it was freshly painted.
Materials you need:
Varnish, a large brush, proper ventilation, a flat surface.
Warning! Varnish Is Toxic
Varnish is toxic and should only be used with proper ventilation. Read the instructions on your varnish and follow the safety precautions.
When Should You Varnish a Painting?
Your painting should be thoroughly dry
You should wait 6-12 months from the last time you worked on your oil painting until you apply varnish. Personally I would not varnish a painting if it has not been dry for at least 12 months.
Why Wait So Long?
There is no consequence for waiting, but there could be severe problems with your painting if you do not wait.
There are many problems that can occur if you have wet paint beneath your varnish. The layers may not be able to fully dry which would cause problems with the bonding, especially if you paint thickly. This could lead to cracks in the painting and difficulties with any kind of long term restoration involving the varnish.
How to apply varnish
The key to applying varnish is to focus on consistency. The final appearance should be smooth and glossy. Varnish should make your painting look wet, but not be noticeably visible on the surface.
Watch Out Below!
Be cautious about the area where you apply the varnish because it is extremely sticky and can ruin nearly any surface it sticks to. I always keep a drop cloth beneath me while varnishing in case any falls off of my brush.
Use A Sturdy Brush
You need a large brush that will not lose its bristles. Varnish is very sticky! The process will be much more tedious if the hairs of your brush get stuck in the varnish.
Pour Into a Jar or Noncorrosive Container
Ideally you should have a surface like a glass jar to pour the varnish into. Avoid materials like styrofoam as they can easily corrode.
Spread the varnish out as thin as possible in long brushstrokes. You want to smoothly brush all the way across the entire painting.
Look For the Reflections
You should be able to see the reflection of the varnish. That will be your guide for figuring out what areas still need more coverage.
Dealing With Impasto
When you cover impasto, or more thickly painted areas, you should brush over it gently while still trying to get even coverage. Do not press too hard or the varnish will get pulled out of your brush in excess.
What If There's Excess Varnish?
If you have too much varnish in any area then you should brush it outwards onto a more dry area. This balance is difficult. This is where it is convenient to have a painting tray or glass jar. You can use your brush to take absorb the excess varnish and wipe it back out onto a dry spot of your jar or painting tray.
Aim For An Even Finish
Smooth out the varnish until the entire surface is evenly covered. In the end the entire painting should appear wet and glossy, but there shouldn't be any visible varnish build up or dry spots. Look for the reflective light from a side view of the painting to see how even your finish is.
Fix Mistakes Quickly
The varnish dries pretty quickly and will begin to become tacky soon after application, so if you have any irregularities you should fix them quick!
What Kind Should I use?
Varnishing Finish Options
The main options when it comes to varnish are matte, glossy, satin, or retouch.
Matte varnish will have a more flat or dry appearance.
Glossy has a wet or shimmering appearance.
Satin is the mixture of the two but more on the glossy side.
Retouch varnish is meant to be used only as a temporary protective layer.
The Best Varnish For Oil Paintings
I would recommend either glossy or satin varnish as these have the best finish and are made for the long term. These will keep your painting looking fresh which is practically the main reason for varnishing!
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