From: Peter Fredrik (pete@fotem.demon.co.uk)
Date: 01/30/01-02:05:01 AM Z
Hi Sandy
Sandy King wrote:
> Peter Frederik wrote:
>
> > For instance I was the first one to suggest sunflower oil in this context
> >.However
> >since then we at The School Temperaprint have found by practical experience
> >that
> >sunflower oil is OK in the short run, it is a No- No in the long term ,it
> >dries out
> >goes yellow and rancid in about a year .
>
> Since you bring up the question of long term use I wonder how your color
> temperaprints (which use egg as the colloid) might fare? We know that one
> of the fatal flaws of albumen prints is their tendency to yellow over time,
> for which there is no known remedy, a condition apparently uniquely
> attributable to the egg. Can the temperaprint escape this fate?
>
> Sandy King
The simple answer to this question is I just don't know. This is one of the
problems of having a unique process where one has no historical evidence to rely
on. However we do know that it is a very similar process to tempera painting
which has been around for a very long time, firstly as medium in early cave
painting then to adorn the Egyptian temples and recently employed in mediaeval
times to decorate churches and cathedrals . Also the mediaeval monks used
albumen and ground precious stones to decorate there bibles and manuscripts with
no yellowing effect.
I have had the process archival tested ,when it rated 7/8in in the blue wool
test and have work on my gallery wall of Petes Parlour dating back to 1987 which
shows no change in colour or light fastness.
Yes Sandy I hope it will escape the yellowing effect because it uses a system of
imaging which is totally different to albumen .The yellowing associated with
that process is thought to be due to residual compounds of complex silver
sulphides, which are associated with silver based imaging ,reacting with the
egg.One could easily ask the same question about carbon in comparison to the
yellowing of silver gelatine emulsions ? . No I am convinced that a dichromated
colloid system is a totally different beast and will not react in the same
manner, but only time will tell !
Pete
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