Egg Tempera Forums

Go Back   Egg Tempera Forums > The Forums > The Forum for Tempera Painting Issues

The Forum for Tempera Painting Issues Sharing the knowledge and experience of fellow tempera painters.

Reply
 
Thread Tools Display Modes
  #1  
Old 31-05-14, 12:23 PM
markbriscoe markbriscoe is offline
Junior Member
 
Join Date: Dec 2009
Location: Spain
Posts: 15
Default Broken emulsion

Hi, I am having problems with my tempera medium de-emulsifying (if thatís the correct word). I am pretty much using the same formula as I have always done but I have never had this problem before.
It is a blend of yolk, linseed oil and damar resin (damar lumps dissolved in turpentine). I add a little vinegar and clove oil for preservation.

I used to be able to get a good stiff emulsion. It is still emulsifying but itís a bit limp and sometimes it completely breaks down so that the oil and pigment start separating. Does anyone know any common causes for this sort of problem, and can anyone recommend any substances that will encourage the emulsion to stiffen?

Many thanks
Reply With Quote
  #2  
Old 31-05-14, 03:22 PM
Salamander's Avatar
Salamander Salamander is offline
Senior Member
 
Join Date: May 2003
Location: Oceanside, CA
Posts: 340
Default

are your eggs old? too much vinegar? how long does it take to "de-emulsify"
Reply With Quote
  #3  
Old 31-05-14, 08:13 PM
markbriscoe markbriscoe is offline
Junior Member
 
Join Date: Dec 2009
Location: Spain
Posts: 15
Default

Thanks for your response. No the eggs are fresh. I usually add between 3 - 6 drops of vinegar. It now occurs to me that I recently bought a new bottle of vinegar. could it be that perhaps? Re how long does it take to "de-emulsify" it sometimes takes 24 hours. other times 3-4 days.
Reply With Quote
  #4  
Old 02-06-14, 06:11 PM
markbriscoe markbriscoe is offline
Junior Member
 
Join Date: Dec 2009
Location: Spain
Posts: 15
Default

A quick update, I tried mixing a medium without any vinegar and it hasn’t proved to be the source of the problem because the emulsion started to break down again after just a few hours. I have experimented adding vinegar to small amounts of the medium and ironically it actually helps to bring the emulsion back. I have only ever used vinegar as a preservative and was unaware how it can aid emulsification.

I seem to remember reading though, that it’s not good to add too much vinegar as it can affect certain pigments. Is that correct? (perhaps I should start a new thread on this one) otherwise I would like to experiment using larger quantities of it. I noticed just now a thread you (Salamander) started back in 2007 about using white wine in an emulsion, sounds interesting, will try (hope a reasonably cheap variety will suffice) there’s a lot there in the thread about vinegar also, with little mention of adverse effects on colours. useful stuff… Any thoughts on possible long-term corrosive action of the acid present in wine or vinegar? any feedback welcome. Thanks again…
Reply With Quote
  #5  
Old 09-06-14, 12:11 AM
dbclemons dbclemons is offline
Senior Member
 
Join Date: Mar 2006
Location: Texas
Posts: 228
Default

I've not had this happen to me when making a painting medium, but it has happened while cooking or making vinaigrettes. It seems to matter if the ingredients are too warm. You can try adding a teaspoon of cold water to the yolk before adding the oil, or use cold vinegar. You might also want to mix the vinegar with the egg first, before adding oil. Using too much oil can also cause problems. Be sure to add the oil very gradually, a drop at a time at first, and vigorously whisk it for several minutes.

Some pigments are sensitive to acids, such as ultramarine blue and lake pigments.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:00 PM.
Design modifications, graphics and CSS by RobM
June 2010



Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.