Basics of oil painting: What to expect when the work is done

Lets start from the end. Knowing what can happen afterwards may help you to make wiser decision in process of painting. Oil paints are tricky, they can ruin the gratification from a beautifully done work even when the painting is already finished.
Here is a list of “sweet surprises” that you need to expect (or at least be ready to) when you think that everything is over.

1. Parts of your painting became matt while others stay glossy (or even the whole painting became matt)

The left side is already varnished 

The most common problem. You’ve come back to the done work a day or two after and you see that the shiny parts became dull and matt.

Cause

- too much turpentine or white spirit
- bad gesso (primer) on the canvas
- the properties of some oil colors

My favorite retouching varnish by Talens 

Cure 

- if it's a new painting - wait till it dries and cover it with a retouching varnish. You can continue to work on the painting and paint over the retouching varnish after it will dry
- if the painting was done later than 1,5 years ago and it is completely done – use the finishing varnish. Why do you need to wait for so long? It’s the approximate time that gives the ability for every layer of paint to dry.

Bad idea: oiling the painting. It simply won’t help.

Tip

- never use super cheap canvases. The gesso on them is so bad that you'll end up struggling with it - it will suck all the juices from your oil (= all the oil from your paints)

2. The painting yellowed

Photo by Sarah Murray Art Restoration & Conservation

Cause 

- unbleached linseed oil was used and the painting was stored in a dark place for a long time
- bad varnish

Cure

 - put it to the sunny place - close to the window is enough
- (if the problem is with varnish) remove the upper layer and cover the painting with a new better varnish. I don’t recommend to do this without the help of professional

3. Craquelure – many small cracks 

This effect is commonly used to make a painting look old

Cause

- too much siccative (drying medium)
- bad gesso (primer) on the canvas
- the painting was varnished before the layers of paint completely dried
- the next layers of paint were applied before the previous dried
- fluctuation in humidity and temperature

Cure

- visit a professional art restorer or pretend that craquelure was the part of your plan

4. Dark dots on the painting 

Cause 

- the paint was thinned with pure oil (linseed) without the turpentine

Cure 

- repaint those parts over

Tip 

– some artists recommend to paint the first layer using pure turpentine as a thinner, even if on next layers you would use the “3 in one mixture” (turpentine + oil + varnish). By the way, I definitely need to write an article about the thinners

5. Dust/oil/dirt over the painting 

Photo by TheArtRestorer.com

Cause 

- storage

Cure 

- wipe with a dry cloth. Do not push the canvas, be gentle

Is there any cracks on the painting? Do not use water/soap. Go straight to the professional renovator. No cracks? Read what to do below.

- wipe the painting with a cloth soaked in water. If the painting has a relief (impasto) use a soft brush or even a soft toothbrush soaked in water
- use a cloth soaked in weak (soft) soap solute. But be aware - before you apply water or water-soap to the whole painting – test it on the small part

Tip

- better if you will use a white cloth to see immediately if it gets colored

Before and after by Foreground Conservation and Decorative Arts
They have an impressive works in portfolio

Almost each of these mistakes can be prevented by using the right technology in process of painting so be mindful.

 Next week – the article about thinners.