How to fix scratch and trying to varnish without dust

edited January 14 in Technical Support
Fixing the scratch: I waited six months and was finally going to varnish this and take it in for hi-res image to enter it into a competition. Had a brand new fine brush and was dusting it and slipped. That's an 11cm/4.5" scratch. It's not deep - I can't feel a gouge. Apart from mixing up all those subtle colour shifts does anyone have other tips on fixing it? This is just a very small section of largish painting.
Cleaning: I was cleaning it with cotton buds and a little saliva. I noticed paint on the cotton bud which implies pigment not bound. Is that normal? Does it need oiling out?
Varnish: I may one day shift to spray varnish but currently have bottle of gamvar to finish. I need to do it in dusty shed and seriously, don't want it impregnated with dust. I decided to clean section of workbench and create a tent using a new painting dropsheet. Any better ideas?

Comments

  • Abstraction

    Fixing the scratch: treat the scratch area with similarly coloured glazes. Wipe off excess to maintain subtlety with each coat. Use Liquin and allow 24hrs in warm air to dry between coats. This is a progressive, step by step, reversible  cure.

    Cleaning: After six months the skin will be pretty hard but the thicker bits will still be mushy. Oiling out will not assist or accelerate polymerisation. Heat and time will.

    Varnish: If your new drop sheet is cotton ( most likely ) it will deposit a thick layer of dust and fibre on the sticky varnish. Construct a polyester or linen tent. A polythene tent with fly screen vents is also a good option.

    Denis
    Abstraction
  • Brilliant Denis. The liquin is quick drying also which is helpful.
    For this painting I was still using solvents in my paint occasionally for some of the fine work (Michael James Smith occasionally does.) I may have some unbound pigment.
    The drop sheet is polythene and unopened. I hadn't thought of vents, great thought.
  • edited January 14
    @Abstraction, you could fix the scratch with a glaze as @Dencal advised. Or, you could paint over it directly by mixing the relevant colours and applying them over the scratch with a tiny brush. It's only in the dark areas that the scratch is really visible and the dark there looks like it should be easy to match. By the time you varnish it the part of the scratch over her face would be even less visible.

    Not sure why you need to clean it after only six months. Did something happen to it? If you used a lot of solvent the paint may not be strongly bound with oil and that may be why it is coming off on the cotton bud. If that is the case then  a thin layer of oil may help bind the paint but you would then need to wait some months before varnishing.

    With the varnish, I'd do it outside on a calm day. This would save you all the rigmarole with drop sheets and tents and there'd be no ventilation problem. 

    Hope it goes well.  :)
  • tassieguy said:
    Not sure why you need to clean it after only six months. Did something happen to it?

    With the varnish, I'd do it outside on a calm day. This would save you all the rigmarole with drop sheets and tents and there'd be no ventilation problem.
    It was just spot cleaning here and there, not a full clean. But the unbound pigment is a concern because it will adhere to varnish and disappear upon removal if that ever happens. Yes, solvent. I had watched Michael James Smith use solvent for fine areas and only discovered after this painting the damage this can cause. Oiling out is a yellowing risk, but more visibly so across blues and whites. Well, big sections are the ocean and the waves aren't they. I'll do an audit-style spot check across various sections to see how localised it is.
    So do you just varnish outside on a calm day without problems? Sounds like an easy solution. If you can do that in Tasmania, I can probably find a decent day in Melbourne also.
  • Cheers, @Abstraction.

    If you oil out that might solve the problem of unbound pigment. But if you do so you'll have to wait a few months before varnishing. 

    The smell of varnish makes my head spin, it's volatile, toxic stuff, so I only ever do it outdoors. We do get a few calm days down here. But I often don't need to varnish because I don't use solvents in my medium, I just use walnut oil, and this imparts luster. And, anyway, when I have to have paintings ready for the next show, I can't wait months to varnish them. They are sold as is. The gallery tells people they can varnish them after a few months. I lived in Melbourne for 30 years - you get lovely calm autumn days there. Like here. It's the best time of year.  :)
  • you know I hate this thing when a scratch or some patches taking place esp. when it's going for an exhibition or getting sold. liquin is really quick. I prefer to match the colors and paint that area. problem is when there's a deep scratch and you have till fill something inside that scratch. I remain nervous during cleaning. there are some putty used by conservators. A retouch varnish by W&N after the overprinting would be great.
    Abstraction
  • Abstraction

    How is it going. Any progress?

    Denis
  • Thanks for asking Denis. I used liquin. I found it a little difficult because the paint didn't want to penetrate the fine scratch (it just wouldn't) - neither did I want any impasto because it's mostly dark (it will catch light) and I need it to dry quickly for varnishing by at least mid-Feb. To ensure unity I painted in several sections of the rock face in case it dried a slightly different shade. So it's a thin layer with liquin to speed drying.
    I decided I'll take some scrap canvas board and replicate what I did in several places. Then I'll varnish these at different times (1 week, 3 weeks, etc) to see what happens - does it lift pigment? Does it crack? It might be informative for any future patching.
    I also wondered if you can patch varnish. Can I varnish 98% of the painting, leaving those pieces untouched until later? I understand gamvar melts the previous varnish so it should bond well - have to check that idea.
    dencal
  • @Abstraction - As you might remember, I do not varnish.  However, I have bought some Gamvar satin and have been experimenting. I paint using Liquin. If I put on a coat of Gamvar, wait a few days until its completely dry, and then put on another, second coat, it does seem to pick up and dissolve the first coat, but it also leaves a slightly different sheen where it was applied over a first coat. I don't know if this is due to my inexperience with varnishing, or an effect of the varnish. Either way, I would suggest that you varnish the entire surface in one application, just in case this is an effect of the varnish. Problem-avoidance is easier than problem-solving - especially with a show coming up. 

    Please share how it works out, so we can all learn. 
    dencalAbstraction
  • I’ve tried varnishing only an area with gamvar and I ended up just revarnishing the whole painting to get it to have a consistent sheen.
    Abstraction
  • Thanks @Desertsky and @GTO I think that stands as fair warning. No partial varnish. Be patient.
    "Liquin will approximately halve the drying time of an oil colour, depending on the proportions added. The climate, colours used and film weight will also play a role in the timings, so the layer will be touch dry in between one and five days.""Griffin can be varnished after drying for three months."
    Griffin is alkyd based and they suggest waiting 3 months - reinforcing half the time of artist oils (they affirm 6 months - https://www.winsornewton.com/uk/masterclass/varnishing-your-painting/)
    I think the amount of liquin I used and the thin surface layer accessible to oxygen will help. So I will do the experiment on spare canvas board and see what happens.







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