Alligatoring - how to address it

edited September 2021 in Drawing
Oil on board. Gamblin oil ground. I realised too late that the second layer of ground was probably too thick and oil settled on the surface. This gave me adhesion problems due to lack of tooth. I lightly sanded the areas I hadn't painted and it solved it. But in other areas this textured pattern had already happened.
This is just very initial underpainting - a sketch really because my subject has so many architectural details I needed good placement with. I used liquin to thin the paint and help it dry more quickly - bad move really, I now realise. It resulted in this texture. It's not cracked, it's just raised in tiny ripples. I didn't think anything of it when I first saw it as I assumed i could just paint over it. George O'Hanlon on another site called it alligatoring and said the only solution was to remove the offending layer of paint. I've asked for clarification and haven't heard back yet.
There are many, many hours invested in this large work already, including blocked in faces of my four children. This appears in maybe 10% or so of the work - on the sides which I intend to darken as the work has chiaroscuro.
My questions:
1. Is this considered a big flaw in art if this kind of texture is seen anywhere on the canvas? Like - art shows and artists would write off this work? Obviously it wouldn't look as obvious as this.
2. Have you experienced this before and found solutions? Other than remove the paint?
3. Is it possible to paint over it without the texture coming through?
4. Is it ok to lightly sand it (eg1200 grit) with sanding block to remove tops of tiny ridges? Of course, they will show up as different colour and might need opaque paint to rebuild again.
5. If I have to remove it, what is the best way? Some other areas had multiple layers of glazes - with liquin.
I'm discouraged I have to say.


  • dencaldencal -
    edited September 2021


    Last updated: April 9, 2017

    What Does Alligatoring Mean?

    Alligatoring is the large formation or pattern of shallow and deep cracks, whichlook like the skin of an alligator or crocodile on the surfaces of:

    • Paint with limited flexibility, excessive thickness, top coat that did not bond well or shrunk faster than the underneath layer
    • Hard paint over a softer or partially dried undercoat/primer
    • Bitumen, asphalt
    • Other coating materials that have been overexposed to the environment or are too old

    Alligatoring is also called crocodiling or chip cracking.

    From my reading and observations I don’t think you need to SNAP to it to fix. Caused by shrinkage and a failure across the van der Waals bonds in a material.

    This crazed pattern in fresh paint is very shallow and pretty stable. (Ain’t seen a pic yet) On old paintings and ceramics this is a desirable feature that people pay thousands for.

    One suggestion is to gently heat the surface. Experiment with hair dryer, heat gun or leaving in direct sun.

    Else, scrape back affected area/s and apply a tinted primer to refresh the surface tooth.


  • edited September 2021
    I can't see a picture of what you're talking about @Abstraction but recently I noticed a sort of rippling texture on a painting I was doing. You may remember the discussion in another thread about my error with lighting and using a tablet screen. Well, I had to repaint that picture and hoped I'd just be able to just paint over the top of what I'd already done. I tried that but I got that rippling effect you speak of. The paint beneath wasn't fully dry and I had lost the canvas tooth and so I think adhesion was a problem.   Anyway, instead of painting over I realized I'd have to scrape down before repainting. That seems to have solved the problem but I should have scraped down more carefully as there are still a few problem areas.  So, I think O'Hanlon may be right.  Scrape down and repaint.

  • 'Scrape back'. How do you scrape dry paint off? Without gouging?
    Is there any problem with using wet and dry sandpaper? When using a firm sanding block it can target the ridges and level it without having to remove everything.

  • Ah, yes, I forgot it was dry. Sanding back sounds like the way to go. 
  • I contacted Gamblin. I indicated that it was at least a month before I started painting.

    Response from Gamblin: "Oil Ground cures very quickly. After 1 month, your ground would be fully dry- even if the 2nd application was applied in a thicker application. The 2nd layer may have been too slick and needed tooth.

    The first coat of Oil Ground should usually be touch dry in 2-4 days. A second coat takes another 3-5 days to dry and cure in warm weather and 5-7 days in cool and/or humid weather. Temperatures below 65F and/or high humidity may add several day’s dry time. In general, plan for 7-10 days from start to finish before painting on freshly applied coats of Oil Ground. Again, the thinner the layers, the faster it will dry.

    If the Oil Ground was applied thickly and dries to a slick finish, lightly sand with 150 grit sandpaper to reestablish surface tooth.

    Yes, it’s more likely that an “over smooth” surface of ground + using a fatty oil medium caused these rippling / wrinkling issues.

    Sanding back the surface will help and you can start over. Our other advise would be to dilute your alkyd medium with some Gamsol or another mineral spirit to lower fat content, which would be more appropriate for an underpainting technique. What can also cause rippling or winkling is when too much fatty medium is added to oil color. Diluting the medium by cutting it with some solvent will likely help prevent this."

    She confirmed that I don't need to remove all the paint (as someone on another site suggested there might be 'traction' which could cause potential cracking later), but I can sand back the just ridges as long as I have sufficient tooth for the paint to adhere.

  • Thank you for passing this information on.   I am sure it will benefit many of us at one time or other.  Looking forward to seeing the end result.
  • edited October 2021
    Indeed. And make sure you address it before the work gets snapped up or you might get a bad name as a shoddy craftsman who likes skinning hapless reptiles for fun. 
  • So for the first time since I first posted this I had a weekend of painting that felt like I was getting control of my painting again. Since I started this post, little by little I had to sand back areas I had painted. It felt like I was sanding my own heart for some reason. It was the opposite of how I feel when I paint. Hours and hours of work measuring out and accurately painting architectural details - gone. Fabric and other sections - gone. Relaid a white for even surface using this time cremnitz and titanium. Then in one area of glazing - cracks or I think scratches were showing up. Finally I sanded back those areas again and laid a new foundation of Gamblin ground. Success. Perfect. A lot of these weeks were spent waiting for sections to dry (learnt the fingernail test - press your fingernail into the paint. If it makes an indentation, it's not ready to paint over.) Last few weeks I've been repainting in the architectural details and this week sections of table. I'm nearly back to where I was before I realised the rippling had to be removed - that there was no alternative. Hard lessons, but I know a lot more about technical painting than I ever did before. I can work with my materials better in future.
    Art reflects life -
    1. Sometimes you have to face your mistakes head on. And that's often where deep learnings happen.
    2. There is always a best move from wherever you are right now, no matter how dire it seems.
    3. Don't respond to life in reaction, because the amygdale isn't logical and beautiful and creative in its thinking. Find that centred place inside yourself where you can see clearly and respond with your best.
  • I agree, @Abstraction. Sometimes there's just no other way but to scrape/sand down and redo. But, as you say, it's hard to do when a lot of work went into it. 
  • @Abstraction – I like your art reflects life observations. Also, I too sometimes find it difficult to sand away, repaint, or throw away unfixable paintings. I think your sanding away the problem areas is permanent fix in which you will have confidence later on. BTW, my amygdala disagrees with you: it is the center of its universe and rules the roost :) 

    Some random thoughts:

    A ground for an oil painting is not necessary, but it can be very helpful. I was taught to paint directly on sized canvas. Since you are painting on a hard substrate – not canvas – I think using grounds would give you more confidence in a well-constructed painting.

    This may not be your final version of the painting, so have fun and hopefully have a sense of freedom in painting it.

    If you decide to do the painting again in the future: choose a size which is easily framed in standard dimensions, can easily be transported, and choose materials with which you are already familiar (sealers, grounds, etc.). I try to not attempt too may different things in the same painting, both in terms of materials and techniques. It makes it easier to diagnose problems.  

  • Very true @Desertsky. I bit off too much: new materials, techniques and approaches to painting all at once.
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