Campos & Davis Photos (photos@campos-davis.co.uk)
Sat, 17 Jul 1999 11:59:55 +0100
WE cant be talking about kerosene then!
Campos & Davis Photos
6 Cranbourne Road
London N10 2BT
Tel/Fax + 44 181 883 8638
email: photos@campos-davis.co.uk
WEB SITE: http://www.campos-davis.co.uk
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> From: Wayde Allen <wallen@boulder.nist.gov>
> To: List: altphoto <alt-photo-process-l@usask.ca>
> Subject: Re: laser vs inkjet
> Date: Friday, 16 July, 1999 4:21 PM
>
> On Fri, 16 Jul 1999, Campos & Davis Photos wrote:
>
> > We make lots of jam, but have never heard of sealing the lids with
> > paraffin.
>
> Actually, it isn't so much sealing the lid with paraffin wax as it is
> making a lid out of paraffin wax. All that is done is to melt the
> paraffin and pour it onto the surface of the jelly or jam in the jar.
The
> paraffin solidifies to form a cap that seals the jar. At this point a
> metal lid is kind of optional.
>
> > the back of paper negatives to make them more transparent. It is cheap
and
> > easy. It arrives as liquid in a bottle. One person on the list send a
very
> > detailed description of what the difference was but I cant remember it.
>
> I think it was decided that the liquid you are talking about is what we
> call mineral oil. Let's see, my dictionary says:
>
> mineral oil - any oil found in the rock strata of the earth;
> a) petroleum b) any of various colorless, tasteless oils
> derived from petroleum and used as a laxative
>
> paraffin - 1. a white, waxy, odorless, tasteless solid substance
> consisting of a mixture of straight-chain, saturated
> hydrocarbons: it is obtained chiefly from the distillation
> of petroleum and is used for making candles, sealing
> preserving jars, waterproofing paper, etc. 2. Chem. any
> hydrocarbon of the methane series 3. [Brit.] same as
> kerosene
>
> kerosene - a thin oil distilled from petroleum or shale oil, used as a
> fuel, solvent, illuminant, etc.; coal oil: also, esp. in
> scientific and industrial usage
>
> These are all definitely related and obviously not mutually exclusive
> terms.
>
> > I cant think how you could be using this to seal jam jars, and also
what
> > is the purpose of sealing them? The high sugar content of jam ensures
> > the jam stays preserved for a year or more.
>
> That is true, however the sugar is hygroscopic and will absorb moisture
> from the air. A little water, sugar, and the added food value of the
> fruit and pectin makes a nice culture medium for mold growth on the
> exposed surface even though the bulk of the jelly is relatively well
> preserved.
>
> - Wayde
> (wallen@boulder.nist.gov)
>
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