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  • question on spray lacquerApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2020-02-11 21:31:19 ... Most recent comment 2020-02-13 14:02:43
    Industrial and Non-Traditional Products
    Question

    ​I do multi-media work on Ampersand's panels and use multiple coats of Golden's archival spray varnish as a protective coating. Recently, out of curiosity, I lightly sanded Golden's gloss varnish and top coated it with 2 coats of nitrocellulose lacquer. To  my surprize, nothing terrible happened, at least visually at this current moment in time. 

    I understand that lacquers are a no-no do to their propensity to crack and amber with time. But, could they be used on top of an archival varnish solely for the purpose of aesthetic reasons? I have always been told that brittle products can't be used on softer ones, but I have been asking myself: so what if the nitrocellulose lacquer cracks and slightly ambers in 100 years? (A person I spoke to from a lacquer manufacturer told me that today's Nitrocellulose lacquers are not the same as the ones first developed), that they take a much longer time to crack and significantly yellow).  As long as Golden's archival varnish is the actual protective layer (used as the permanent layer), couldn't two thin coats of spray lacquer be removed by physically sanding it off? And since lacquers re-wet themselves, couldn't the picture just be recoated with new lacquer, or a new invention(hopefully after a 100 years) that isn't so plastic looking?

    Grateful for any thoughts,

    Kim

Answers and Comments

  • EditDeleteModerator Answer

    There are a couple of issues that you haven’t considered. First, depending on the solvents in the CNL, it most likely bit into or even dissolved itself into the lower MSA varnish making the scenario you mention impossible. Generally, the solvents used for CN are hotter (read more aromatic or more polar) than those used as typical diluents for fine are varnishes. It is true that current CNL are different and perform better than earlier formulations, they are still a very poor coating for organic paint layers. They may, and I emphasize, may, have a place in coating metals with high surface energy and that require a completely covering coating to prevent corrosion (eg silver objects). Even this is debatable, and I foresee the abandonment the use of CNL for silver coating in the relatively near future.  

    It is always best to apply more flexible coatings over less flexible coatings/layers for very simple and understandable concepts. Why deviate and for what gain. If there is an aesthetic goal, I could understand but what does a surface coating of NCL gain you; a super smooth/super high gloss surface coating? I would suggest that this could be achieved using less drastic measures.

    Finally, you do not mention if you intend on using this rather dubious material, in terms of fine art application, on a work executed on a rigid or flexible substrate. If the former you can probably get away with it in the short term, if the latter, this is likely a poor decision.

    Brian Baade
    2020-02-11 22:05:42
  • ApproveRejectUn-ApproveUser Comment

    ​Thank you for your comments. I realize my query is a bit odd. 

    I am working on cradled Ampersand pastel boards, using mixed drawing materials, without paint.  I'm using a hard substrate with varnish to eliminate the need for glass, and  use gloss coatings because I don't like the flattening agents in satin and matt finishes. I then rub(or buff) out the gloss physically to eliminate the glossy sheen. I can do this with Golden's varnish itself, but I find that buffed-out lacquer looks nicer as a coating(not so plastic looking).  It's also very convenient because it's very easy to apply thin coats that dry quickly. Frankly, I was expecting the lacquer to entirely lift Golden's Varnish, but then I looked at the solvents in Goldens(acrylic) Varnish: Acetone, propane,n-butane,solvent naphtha...Well, I don't understand the technology.

    Thank you for bringing attention to how a nitro lacquer would disolve the under layer. Do you think I could test the surface by sanding the lacquer off? If I sanded the top layers off, and were able to remove Golden's varnish with mineral spirits...would this indicate that I could use the lacquer without damaging the purpose of Golden's Archival varnish layer? 



    2020-02-12 00:54:54
  • ApproveRejectUn-ApproveUser Comment

    ​Brian, 

    There is a second reason why I would like to coat MSA with an alternative coating. When I buff out gloss MSA, the surface is easily smudged. Lacquer does not behave like this. 

    In any event, is there an alternative spray coating system that might work for my purposes? I would like a protective coating that I can comfortably consider archival, but can also be buffed out without leaving finger marks in case it is touched.

    Are you familiar with a product called "Desert Varnish Spray" made by MOAB? It states that it's also a lcquer-based product used on prints, but I am not sure what type.

    Thank you very much,

    Kim

    2020-02-12 02:36:30
  • EditDeleteModerator Answer

    Hello Kim,

    Pretty much all picture varnishes are thermoplastic resins and would become soft when touched by warm hands and leave finger prints. Harder, thermoset resins, which are resistant to impact damage and finger prints etc, are generally very difficult, if not impossible to remove in a conservation treatment. Sanding down a coating without damaging the layers underneath would take tremendous skill and while you might be able to do that to an extend that meets your standards, it is unlikely that you'd be able to differentiate between the MSA Varnish layer and the lacquer once the surface is roughened up. If the lacquer layer is thinned down a little by sanding you might be able to remove the rest by using a solvent that removes the MSA Varnish. MSA Varnish is removable in aromatic mineral spirits or turpentine and the solvent might 'undercut' the lacquer, so that you might be able to remove both layers in one go. But this is not something we have tested and not necessarily a recommendation. Maybe you could consider putting your painting in a frame so that there would be no need to touching the artwork itself when handling. That would allow you to choose a removable picture varnish that produces a finish you like. 

    Mirjam Hintz
    2020-02-12 04:01:55
  • ApproveRejectUn-ApproveUser Comment

    ​Mr. Hintz,

    Thank you for replying to my query. 

    I was hoping to find a drawing process that would eliminate the need for glass; I read and see other artists doing this with modern art products such as MSA. But not being able to touch a thermoplastic coating without risking a fingerprint seem counterproductive. 

    I am afraid that my questions might appear ridiculous; but here it goes:

    Golden recommends quite a heavy layer of their product(4 coats) to achieve decent uv protection.  If a light coat of nitocellulose lacquer were spayed on top(for aesthetic reasons and to guard against finger prints) and it started to check years later, wouldn't the check marks indicate the depth of the lacquer? Wouldn't that indicate to a conservationist how much to sand off? And since lacquers re-wet themselves and can be forever topcoated, couldn't it just be re-sprayed. I think musical instruments are sanded down and re-coated this way(they seem to prefer the glossy sheen), thought I am not too familiar with this subject. I understand that this process of sanding could only be done on a very flat surface; my drawings are very flat and I use no paint.

    I guess my thinking is reversing the use of MSA and nitrocellulose lacquer: MSA is designed to be removable and lacquer is intended as a permanent protective coating.  When I contacted Golden, they told me that MSA can be used as a permanent coating. And since lacquer does not have archival qualities, I was thinking it could be used as the non permanent top layer; it seems a very sandable substance.  So my process would be: cradled ampersand boards, various drawing materials, 4 coats MSA, 2 thin coats nitocellulose lacquer.  If the NCL could be sanded off, and this actually works, would my artwork meet the definition of "archival" from a conservationists point of view?

    Thank you,

    Kim

    2020-02-12 10:21:38
  • EditDeleteModerator Answer

    I will let those at Golden comment about their products but no, as a conservator, if it requires sanding, it is not archival. That is even avoiding the nebulous definition of archival.

    Brian Baade
    2020-02-12 11:10:26
  • ApproveRejectUn-ApproveUser Comment

    ​Mr. Baade,

    Oh, I see. Thank you very much for your time, and I welcome a response from Golden. Thank you very much.

    Kim

    2020-02-12 11:29:02
  • EditDeleteModerator Answer

    Hi Kim,

    We, that is Golden, recommend 6 spray coats of the Archival Varnish, which is comparable to 2 brush coats of MSA Varnish, and should provide the most UV protection. As I said earlier you might be able to undercut the lacquer and remove the Archival Varnish together with the lacquer, especially if the surface was roughened up a little and the solvent has better chances to penetrate down to the MSA coat. But this would be a very unorthodox approach. A simpler solution would be a frame, even without glass, that would allow you to pick up and handle your paintings without touching the surface. There are varnishes with resins of smaller polymer sizes which have less of a 'plastic' look, for instance Regalrez 1094 sold by Gamblin and Natural Pigments. Should the Regalrez require removal at some point you could do that with OMS without removing the MSA/Archival Varnish. 

    Mirjam Hintz
    2020-02-13 05:33:50
  • ApproveRejectUn-ApproveUser Comment

    ​Mr. Hintz,

    Thank you so much for your reply. After learning about MSA and others like it, I am afraid I will have to find a different route all together. I live in Florida and work in my garage; perhaps this is why I have had such difficulty using MSA? 

    So very grateful for your time and expertise.

    Kindly,

    Kim


    2020-02-13 14:02:43

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