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Unbound pigment due to solvent use

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About to varnish oil on panel large seascape/ coastal rocks painting that took me many months due to high level of detail. Yes, waited six months. This is a major work for me. Discovered in spot cleaning with cotton bud and saliva that with a decent rub pigment lifts off in places. A light rub doesn’t really remove much at all. I did use solvent in some places to thin paint (following example of well-known Youtube artist) – it was prior to me setting out to learn about good painting practice.
Looking for advice in terms of pros/cons for next steps. Life isn’t black and white, complexities with pros and cons make sense and are welcome.

Options:
Oil out: Risk of yellowing. I assume dark yellowing less a concern if kept in well-lighted situation. Also, good oiling out requires rubbing back which may move/remove the pigment anyway. 
Varnish: Just varnish it – which will bind loose pigment to varnish and create problem later. Perhaps put note on back indicating risk of pigment loss. My plan is gamvar which I was going to brush on. I’m suspecting better to buy a spray? I want gloss and haven’t used sprays – recommendations helpful.

Other: No idea. I don’t want to act until I have the best options on the table.

To be more specific – the painting was completed more than 6 months ago. From an art conservation perspective:
1. How would you determine the degree of poorly bound paint? When I wipe a dry or wet with spit cotton bud across I either get nothing or very light indication of colour in some places. It’s not everywhere. I first identified it just doing some isolated spot cleans which involved more significant rub and resulted in slightly heavier pigment.

2. If you encountered this what steps would you take to protect the painting prior to varnish? I do need to varnish for the rich colours and darks. ​

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A couple of thoughts. If you varnish with Gamvar and are concerned about removability of the varnish due to the sensitive paint layers, the best way to test for that would be solvent sensitivity swab testing with OMS. It might be that more pigment lifts with saliva than with OMS. Applying a varnish from a spray can evenly on a large painting is more difficult than with a HVLP spray gun or with a large brush. When using an aerosol varnish you should be able to cover the entire length of the painting easily within your arm’s reach.
A painting that is sensitive to solvents will pose challenges to conservators either way, whether varnished or unvarnished, but a contemporary oil painting would always be treated with great caution in regard to its sensitivities. For as long as the painting is in your own care or with a collector, it should be easier to take care of it when it’s varnished. ​

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I agree with the above about a number of things. Yes, it is easier to take care of a varnished painting IF that is the aesthetic that you intended anyway. However, if you varnish an underbound painting or one that is sensitive to mineral spirits you will have created interactive zones where the varnish now becomes a part of the biner of the paint and will make removal at a later date almost impossible. The only real options are. 1. Leave it unvarnished knowing that the painting will likely absorb grime which may not be removed. Glazing such a painting would alleviate this but, of course, involves greater expense and the necessity of a frame. 2. Varnish with a super stable varnish like Regalrez knowing that it cannot be removed but also knowing that it is not likely to yellow appreciably in the future. Spraying rather than brushing would avoid disturbing the pigment particles but it is more difficult. 3. And I do not ever recommend this, apply a super thin coat of an additional binder like an alkyd medium to shore up the paint. This will almost certainly result in later yellowing and will likely disturb the pigment during application. In short, do not do this.
No matter which option you go with please make sure to record your procedure and materials on the back of the painting, we have threads and resources on this on MITRA, so that any future conservator knows how the painting was constructed. Additional, you could also state how you would like the work treated in the future (eg, please do not attempt to remove this XXX varnish).

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