My experience with tempera is to throw it out when it gets old and here is
my story why...
Several years ago, I was teaching middle school and had painstakingly saved
all of my old tempera paints that had been in the art room for several
years. I had cleaned out old paint bottles and poured the paints into them
and then arranged them on an open shelf. Well, unbeknownst to me, the paint
had started to ferment (tempera is a corn base). As I was teaching my class
one day, I noticed paint on a stool and a table opposite my cabinet. I
thought for sure that one of my students had squirted it out. I walked over
to look and noticed that paint was now on my arm. I turned to look around
the room wondering who could be so blazon as to squirt paint on me! As I
was turning the paint kept squirting until I had complete circles of paint
around my body!
It turns out that the pressure in the bottle was so great that the bottles
had gotten pin size holes in them and the paint was spraying out. I was
covered! I called my art supply company and was told that the FDA came out
with new guidelines a few years prior stating that the paint companies could
not put as many preservatives into the tempera base.
As a rule of thumb now, I never clean out old paint bottles to reuse AND I
don't buy corn based tempera!!
Becky in NC
From: Jerry & Anne Carman-Hendel [mailto:firstname.lastname@example.org]
Sent: Thursday, November 29, 2001 3:16 PM
To: ArtsEdNet Talk
Subject: Tempera Paint
I know we have talked about old, watery, dry and smelly tempera. I
received a couple of bottles this year that are gelatinous in texture.
What does this mean?