View Full Version : Repairing cracks in a painting TECHNICAL ADVICE NEEDED

04-18-2007, 08:24 AM
I stupidly said I would try to repair an oil painting for the mother of one of my son's friends. She is decorating a new house and she likes the painting, which was stored somewhere cold and damp, but she doesn't want to hang it up with the cracks. What she SAID is that she doesn't care if I ruin it- she wants me to try fixing it and if it doesn't work I suppose she will just buy a different one. It is a cityscape and the entire sky has circular cracks. The other areas of the painting - the buildings and streets etc. are fine. Any advice on the proper way to do this? I was going to wipe linseed oil over the entire painting, let it sit a day and then use thick paint to repaint the affected areas.
Thanks in advance for any help.


04-18-2007, 08:56 AM
Wiping linseed oil over the entire painting is an excellent way to make your painting yellow. About your question; when you walk into a museum with old master paintings, take a look at the ones done on canvas. They're cracked all over the place, and these paintings are in the hands of conservators.. Easy to fix? I don't think so. Store wine and junk in cellars, not paintings, they don't like.

04-18-2007, 09:20 AM
I will post a picture of the painting later. I am not thinking it will be easy but I think I can make it look BETTER. I ti snot an old master. It smells of mildew and she just likes the colors I suppose. She'll pay me $50 to make the cracks go away but the frame it is in is worth more than the painting IMO.
Anyone else? I vaguely remember hearing you could rub a raw potato over the entire painting before reworking it- although I am not sure why....there appears to be no varnish on the thing. it has a very matte appearance.

04-18-2007, 10:49 AM
Circular cracks like you describe can be impact cracks. These are caused by someone poking a foot or some object into the canvas which then shatters the brittle paint layer into spiral cracks. The potatoe that you refer to is sometimes used as a degreaser when there has been an overabundance of oil and new layers don't want to stick to such an oily surface-a potatoe slice will degrease the surface and cause other layers to be accepted. It doesn't have anything to do with repairing impact cracks.
Do you really want to spend a few hundred hours to repair this? Filling the cracks, resurfacing and then matching paint colors in hue, value, chroma and of course sheen?

Mike Finn
04-18-2007, 08:24 PM
Here is something you may try... allowing for the fact that it may ruin the painting unless carefully watched.

Mike Finn

04-19-2007, 06:41 AM
Simply put Nora you can't repair cracks in oil paintings. Professionally they mask their appearance, as well as trying to stabilize the support to minimise future problems but they don't fix the cracks.


04-19-2007, 10:33 AM
OK, Einion, I need to re-word this. Is there a way to camouflage and or hide the cracks in the original oil so that it will look good for another 4-5 years?

My plan is to repaint the entire sky with thicker paint. It is the only part of the painting that is cracked at all. the other parts seem to have a thicker application of paint. I am pretty good at mixing paint and matching tints and as the sky is gray I shouldn't have too many problems. It won't be the "original" but the woman likes it for the colors in it. (IT WILL NOT take me a hundred hours, kazucks- I predict it will take two hours)

I know you all are trying to convince me I should not attempt this but she truly hates it the way it is and will throw it out if it doesn't work so I have nothing to lose and maybe if I mess it up I can buy the frame off her. Or sell her another painting. :evil:

All kidding aside-- is there some special substance I should apply before I attempt this? Sand it lightly? Coat it with mineral spirits? OK- I'll forget the linseed because it yellow. I have walnut oil in my cupboard waiting to be used in a special medium.

There appears to be minimal varnish or none on the painting- it has a very non-shiny matte appearance.

Here is the painting- by someone who signed it "Kressley", translated - generic painting factory person..?


04-19-2007, 10:54 AM
I was not making reference to a simple overpainting with thicker paint over existing cracks. As the oils dry out, and the canvas expands and contracts as all canvas do, the spiral cracks will be repeated in the new layer. I was refering to a more elaborate repair job-although it would be experimental (I agree with Einion that for all practical purposes cracks are not repaired). What you are making reference to is simply a cheap and dirty overpainting which could easily be done in a few hours. Have at it. Have fun. Maybe that is enough to satisfy your friend.
You might consider using an alkyd resin mixed in with your paint, alkyd is extremely resistant to cracking and is more flexible than oil by itself. It might delay repeat cracking some number of years. I would also steel wool the surface of the sky before proceeding to rid yourself of dirt, grime, etc. to allow for a better bond.

04-20-2007, 01:37 PM
OK, Einion, I need to re-word this. Is there a way to camouflage and or hide the cracks in the original oil so that it will look good for another 4-5 years?
Er, well if that's all you're looking for then maybe, but it would depend a bit on the three-dimensional aspects of the cracks. Painting over with more paint might just make for softer-looking effects, while it still appears there's something wron. What I'm suggesting is that it might look like in baking where you put a thin layer of icing over a cake surface that's rough - you can still see that roughness under the sheet of icing.

Anyway, if you want to attempt this - for this kind of limited lifespan - I would take the canvas off the stretchers and bond it to a rigid support (ply, MDF) as the first step. That would be the only way to ensure there's no flexing due to humidity changes that will transmit the existing cracks through to the new paint when hardened.

(IT WILL NOT take me a hundred hours, kazucks- I predict it will take two hours)
In conservation cracks are dealt with by inpainting, which is done meticulously and sometimes under a stereo microscope :)


Simon Bland
04-20-2007, 02:18 PM
I like the idea of getting it onto a rigid support.

You could also try sanding the affected areas and overpainting with oil paint using mineral sprit acrylic (MSA) varnish as a medium. It might give you more flexibility in the new paint layer. You'll be able to varnish the whole painting in no time after that. I'd suggest a matt or satin finish final varnish as it will help to hide the distortion of the surface that the cracks have caused.


04-20-2007, 07:45 PM
I thought I would give you a look at what I've done so far. Thanks to all for your responses, including the person who PM'd me with detailed instructions on how to do it right. I needed to get to it today as I told her I would work on it this week and have something for her to look at next week and I didn't want to go out and buy all those things I would never use again.

Wow- it's Friday already is what I was thinkign as I pulled the tacks out of the canvas- what a cheap framing job! It took me an hour and 20 minutes from start to finsih. After it is dry to the touch I'll view it at all angles and see if the cracks are viewable. I used a pretty bright light and I couldn't see any after i was done but it could sink in a bit. If so- I will go over it again with even THICKER paint.

Basically what I did was sand with steel wool (lightly) the sky area. I rubbed in some archival oils classic medium. solvent, oil, varnish- it is a slow drier. Then I mixed some generic grays from pthalo blue, yellow ochre, and aliz crimson plus a bit of burnt umber. I did a darker blue underpainting gradating from dark at the top to lighter near the horizon. I used a brush to go around the buildings and trees and scumbled a bot of the color into the trees and buildings. Then I loaded the knife with lots of white paint and troweled it on.
Repainted the tiny dark lines that represent something I do not understand on top of the buildings- maybe fences to keep people from jumping?

It's not too bad- When dry to the touch I'll adjust the color a bit with more glazes and scumbling if necessary. Needs to be slightly cooler in places I think.

http://www.wetcanvas.com/Community/images/20-Apr-2007/3589-Repair-oil-painting10.jpg http://www.wetcanvas.com/Community/images/20-Apr-2007/3589-Repair-oil-painting12.jpg