Monday, October 31, 2011

Wednesday, October 26, 2011

Tuesday, October 25, 2011

Hello Mr. Bissett,

I am sooo excited about your page. I made the mistake of using a paint thinner in my parent's small apt and the smell was awful. I realized I could not use this indoors. I wish to faze out my use of toxic solvents bc it also becomes an environmental issue to dispose of this solvent.

I noticed in one of the Methods you wrote something negative about citrus solvents. Are they toxic? I learned of two citrus solvents of interest Livos (info@livos.de) and Extra Mild Citrus Thinner 4oz and other sizes (http://www.artsupply.com/Extra-Mild-Citrus-Thinner-4oz-and-other-sizes_p_61280.html) . Do you know of these? What do you think? Thank you.

V

Hi V,

I found Livos.com and this description:

"For use in diluting LIVOS wood stains, natural oil based products and oil-based cleaning agents. SVALOS is also used for cleaning tools and brushing out resinous woods before priming. It is ideal for removing scuffs and spots. Low surface tension promotes penetration into the wood, cork, etc., and encourages moistening of pigments and surface-active materials. Virtually no solvent retention when dried."

Not sure this would be the best for artist paint because it says 'virtually no' which I suspect means 'actually some'.

Compare with this:

"Eco-House # 125 NeutralThin ® Odourless Thinner...100% volatile..."
115 makes the same claim. That means they completely evaporate from the paint. We use 125 in workshops with no problems so far. It is still a solvent so use ventilation as it does go into the air. I used to recommend Sporny, but it's no longer available.

Hope that helps...

Yours,

Bob

Wednesday, October 5, 2011

Wednesday, September 28, 2011

Letter from Website Visitor

Hi, Robert,

Thank you so much for the valuable information about non-toxic painting method.  Normally I paint oil with a palette knife which has four different edges.  Most time I like my knife marks on the canvas, but sometimes I was frustrated when I tried to get a softer edge or complex organic shapes.  After reading your article on water mixable oil, I began to experiment with Lukas Berlin. I like it because it allows me to use brush, which seems more easy to capture the essence and beauty of certain subjects.

I did this painting yesterday and took the photo when the painting was still wet. I noticed that the paintings made with water mixable oil tend to be duller than the regular oil when they dry.   Is there any thing can be done to bring the luster back to the painting?  if need varnishing, which varnish is non-toxic? 

Thank you!
J...
 

Hi J...

Varnish is a problem for sure. Read this page: http://www.gamblincolors.com/oil.painting.techniques/varnishes.html

I've stopped varnishing these last few years. If you want a gloss Gamvar might be a good choice having about the least toxic solvent available. Water-based acrylic varnishes are non-toxic, but are not usually considered wise to use on oil paintings.

"Acrylic polymer varnishes permanently adhere to the surface, and are not removable. If you must be able to remove the varnish at a later date, use a non-polymer varnish such as Liquitex Soluvar Varnish. Polymer varnishes are not for use with oil paintings." from Liquitex.

"Acrylic paint and gesso should not be applied over oil paint, even dry paint. As oil continues to cure over a period of years, the bond with the acrylic layer will weaken and peeling will result." https://www.utrechtart.com/ask-the-experts/FAQ_acrylic.cfm

"While many artists choose not to varnish finished paintings, there are many compelling reasons to do so....While some synthetic varnishes are subject to the same technical issues as traditional products, conservators regard solvent-based acrylic resin varnishes as the best choice for a final, protective application for oils." https://www.utrechtart.com/ask-the-experts/FAQ_OIL.cfm

However, read the following from knowledgeable poster:

"I hate to be the sole dissenting voice but actually you can use acrylic varnishes on an oil painting, assuming it's completely oxidised - remember once the drying process is over the oil is not oil any longer. I think a better question is "should I", rather than "can I". The refractive index of a varnish is one of its most important characteristics and here dammar far exceeds any acrylic, giving much better depth and brilliance. There are a number of spirit-based synthetic varnishes that may offer better long-term prospects with comparable optical qualities but dammar continues to be a solid choice. An acrylic varnish can be removed with alcohol quite effectively, the weakest solvent used in conservation."
http://www.wetcanvas.com/forums/archive/index.php/t-28768.html

Test it on something from your reject pile. I have painted with acrylics over oil paint by first hitting it with steel wool or pot scrubber. Seems to stick well. You could rub it with a cotton ball which is somewhat abrasive.

I'll try it when I get a chance and post on my website. Let me know what you decide to do.

Keep painting...

Bob

Test: acrylic varnish over oil paint.

Sprayed with water, rubbed and scratched with finger nail. No effect.
Strayed with alcohol and scratched with finger nail...1 above.
Alcohol and rub with facial tissue...2 above.

The painting used for this test was an experiment with lots of linseed oil and a little paint and it was thinly applied. It's hard to remember which of the old paintings are oil and which are acrylic. The varnish adhered fairly well. I used Nova Gloss Medium and Varnish. Alcohol and a little rubbing did remove it and paint, too. More testing is needed.

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