Judy said
"On Fri, 21 Jun 1996, TERRY KING wrote:
> In general, however, a 1% size will give sharper images and better tonal
> definition.
Terry, I assume you mean for other processes than gum."
I did say the 1% gel was for salt, cyanotype etc. In other words those processes
where the upper layer of the paper is the medium for the light sensitive salts
rather than an emulsion of gelatine on the surface. I have forwarded to the list
a note I sent Keith Schreiber in March on the use of the ossein for platinum
printing. The principle remains the same for other 'solution' processes. The
presoak is needed whatever the percentage gel as gelatine dissolves far more
effectively in a swollen state.
"However, here are a couple of questions about your de-ionized :
"L> light.. Coat the paper with the size at this temperature and dry immediately
in
> a flow of warm air. Humidify the paper in a cupboard above a tray of warm
water
> before sensitising."
Again, I assume you mean humidify gelatine for platinum or iron silver
printing -- but why do you dry the gelatine immediately? To keep it on
the surface? If so, why?"
No, it is important to dry the gelatine so that it does not gel on the surface
of the paper where it can dissolve away taking your image with it..
"> For gum use a 3 % size for hardened substrates and inter coat sizing and dry
in
> a flow of warm air.. But despite Judy's protestations the pterotype method
using
> dichromated Gloy works better.
"Terry, you have to define and quantify "works better." I have found that
dichromated gloy gives a less intense one-coat, flakes more and gives
flatter steps on many papers. So what's better?""
I am not very keen on one coat gums; for monochrome printing I prefer almost
anything else. My conclusions were that Gloy gave more consistent results, did
not flake, and gave equal results in tonal range to gum but without flaking in
the greater areas of density. That is why I use it and have been using
successfully for over ten years now.
"> For pigment 3 and 5 and 5 and the same for carbon receiving tissue. >
What does "pigment 3 and 5 and 5" mean, or refer to?"
Percentages.of gelatine in the three coats of gelatine required for oil pigment
printing where you coat the paper with gelatine and the dichromate it and expose
it under a contact negative so that it may then be soaked and inked up like a
bromoil . This is the one area where I do harden gelatine and I use a quarter of
a gramme of chrome alum in an overall solution of 100 ml ( dissolve it first in
another 5 ml from the total 100 ml )
This gelatine is also effective in making up the gel for making carbon prints
where a 10 % solution is used.
When you say "purified water" is that what we call distilled? Do you use
it for gum sizing too? What's the advantage? (Paper is going to be
developed in tap water.)
Purified water is what pharmacists use. It has the impurities removed by reverse
osmosis rather than by distillation. It tends to be sustantially cheaper
especially from health food shops. The purified water is of course not intended
for gum but 'solution' processes such as salt, kallitype and platinum.
Judging by the shouts of joy from the streets England have just beaten Spain in
Euro 96.
All this stuff will be in the book of how I do it, which is of course not the
only way. We need as many books as possible so that we may make our own
judgements. What I need now is Luis's encyclopaedia.
Glad to to give further clarification.
Terry.