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MITRA Forum Question Details

Image Picker for Section 0

 ForumQuestion

  • Polishing an egg tempera paintingApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2019-05-08 17:19:48 ... Most recent comment 2019-05-24 23:03:02
    Egg Tempera
    Question

    Hello! and thank you for this wonderful forum!

    Many ET painters find themselves painting smaller and smaller works but I am the opposite. My paintings tend to get larger and larger. I just completed an 8'x4' ET and it "only" took 2 years! Ordinarily I would polish my painting with a soft cloth: silk, flannel or T-shirt material has been recommended and I have not found much difference between them. Due to the large size, and some physical limitations, I am experimenting with power tools. I've tried a "polishing bonnet" attached to my corded electric drill but am interested in purchasing a dedicated buffer. A Dual Action Random Orbital Polisher  (DA) seems to be the safest option, in terms of not harming the surface,  but I don't want to invest in it unless I feel it will be more effective or safer than my drill buffer or hand polishing. The "bonnets" I am using now are what came with the conversion kit- one is lamb's wool and the other an unknown synthetic. If I get the DA there seem to be endless options in polishing pads. Of course they are meant for automotive polishing. I love traditional methods/ materials but am not one to scoff at high tech improvements. Perhaps the old saw about ET developing a gentle egg shell gloss will be proven a myth once more effective polishers are employed and a higher gloss will be achieved (not that I necessariy want that.) Obviously if I see any paint on my bonnet I'll know the machine is too aggressive or the paint surface inadequately polymerized. So far I have tried it on the edges of my monster ET panel and no paint has come up, nor have I achieved any more shine than with elbow grease. Hoping you might have some experience with this. Perhaps conservators use electric buffers with a variety of pads? If not my path would be clear: buy the DA and try different pads on castaway paintings or trial paintings and see what the effect is. Thanks much for your great work!

    Lora Arbrador

Answers and Comments
  • ApproveRejectUn-ApproveUser Comment

    ​Hello Lora,

    Perhaps the lack of response indicates that you are breaking new ground here - so please continue your experiments and let us know how they work out.

    For the record, the idea that egg tempera is capable of a soft "egg shell shine" (a term I've used myself) but no more, isn't accurate.  I've seen well-tempered egg temperas carefully, gradually buffed up to a lacquer-like high gloss.  My presumption is that this comes from gradually smothing out the irreuglar surface created by the high pigment load in egg tempera; a gentle, careful polish softens the rough edges of particles proturding above the paint film, to create a more mirror-like surface.   If an attentive polisher avoids visibly marring the surface as he or she polishes, I don't know if there are other risks to pulling out a strong shine (such as weakening the paint film).  Do conservators have any thoughts or experience with this?


    Koo Schadler

    2019-05-14 10:55:26
  • EditDeleteModerator Answer

    Lora and Koo

    So sorry to see that this question slipped past us. I probably would have forwarded it to Koo anyway so it is great that she caught our dropped ball.

    I think that you are In safe enough territory if you do not see any pigment on the material/fabric you are using to hand polish, but wow, I do worry about introducing spinning polishers used for enamel paints/automotive finishes. In addition to the risk for over abrasion there is also real potential for damage from the heat created by the rather extreme friction.

    Despite adding another material to the paint I would be more comfortable with varnishing the work rather than resorting to power tools. If you do decide to follow your plans. please tell us the results

    Brian Baade
    2019-05-15 15:32:24
  • ApproveRejectUn-ApproveUser Comment

    ​Hello Koo and Brian,

    Thank you so much for your responses!

    First to Koo, I think we may have stumbled on "Egg Tempera Misconception" #31 in your list? In #28 you mention the "egg shell" shine but in your response to my question you mention that it is possible to achieve a "mirror-like" finish. That would indeed be another misconception as the most common characteristics mentioned about ET (in addition to the "high key") is the "matt finish." So it is exciting to me that I may be able to pull out a lot more shine. I am in the non-varnish camp because I do not want the saturated look of my ET paintings but I would like more gloss.

    Brian your caution about power polishers is well-taken and I promise to try out any power tools on sample or reject ET paintings. The reason I am looking into a "Dual Action" orbital buffer is, "The rotating and orbiting of the pad produces what many refer to as a "jiggling" motion. This irregular motion prevents the polisher from burning the paint, which refers to removal of paint below the clear coat surface. Dual action polishers are very USER FRIENDLY because they produce very little heat compared to a rotary polisher. 

    That said, as you say, they are meant for automotive finishes. I am looking into the type of pads available and most are "foam." There are some that do cut into the surface and others that are for polishing only. There are others that are "microfiber. " The finishing microfiber pads which are supposed to be safer but I need to look into it more. I have not yet sprung for the machine but did order a "finishing" microfiber pad that I thought I would try out without the machine first.

    Which brings me to the question: is there any concensus on the best cloth for polishing an ET? I've heard silk, flannel or T-shirt material. Has microifiber been tried for hand polishing?

    Again thank you both for your sage advice!

    Lora

    2019-05-15 18:23:16
  • ApproveRejectUn-ApproveUser Comment

    ​Hi Lora,

    There's a balance in a polishing cloth between smooth and abrasive - you want enough abrasion to buff the surface, but not so much that a painting is scratched or pigment lifted. I've always found a fine weave cheesecloth to work well; however I've seen many newcomers polish either inattentively or over enthusiastically, and consequently mar the surface, so I also recommend well worn cotton or a piece of silk - both are less abrasive materials and thus safe options for beginners.

    Your idea of using a microfiber is great; I just tried it and fine cheesecloth, side by side on the same painting, and the microfiber gave excellent results (more shine than the cheesecloth).  I would just say that for any newcomers to polishing (which of course you are not) practice with a less abrasive fabric to start or, if using microfiber, do so with attention and care.

    Please let us know about your Orbital buffer experiments.

    Koo

    2019-05-20 10:41:37
  • ApproveRejectUn-ApproveUser Comment

    ​I forgot to say, Lora - yes, another one for my list of Egg Tempera Misconceptions.  I've already added it, up to 32.  Thanks!  Koo

    2019-05-20 11:25:55
  • ApproveRejectUn-ApproveUser Comment

    ​Thank you Koo for your run down on polishing cloths. I recently used some white cotton photographer's gloves and really enjoyed "caressing" my painting double handed without any bunched up cloth. 

    I still haven't sprung for the Dual Action Orbital Buffer. Some brands have a "slow start" capability that seems like a wise feature but adds to the cost. Will keep MITRA posted. Thanks, Lora

    2019-05-24 23:03:02
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