>But this was husband's fortune cooking which I stole,<
Shame on you :-)
>Meanwhile, a couple of questions to Peter:
You said you mixed your colloids "to standard proportions," with a
saturated solution of am di. What are your "standard proportions"?
My experience is that changes in saturation of dichromate, and ratio of
dichromate to colloid, change degree of staining, & am not sure anyway
what is "standard." <
Yes I was a bit woolly on this point , what I should have said the
"standard proportions" were one part of colloid to one part of sensitiser a
50*50 mix
>You note that without pigment you got up to 15 steps of tone, the
assumption being that added pigment would reduce number of steps. In my
experience the addition of a *lot* of pigment cuts down number of steps a
lot. Presumably the pigment blocks up the whole low end, making it the same.<
Yes I have found in previous tests that the pigment ratio can be used to
control the contrast in a dramatic manner, when using Synteape ie
[laminated polypropylene]
I found that I could get a lith like pure drop tone image at a mix of one
part of pigment to two parts dichromated colloid by volume ie level
teaspoonfulls, which is about the maximum before the emulsion turns to
paste.
>I wonder also about stain with different light sources, if they will also
follow the rules you discovered, and if there's a correlation between
stain without pigment and stain with, which there may not be.... In fact
each *pigment* could, as you put it re Synteape, have a life of its own. <
Yes another good point, more info required.
>I'm not sure what use all this is, *unless* it turns out that the stain
in transformed form is not anti-archival & thus could be used as tone
builder... which would be nice on several levels, including no rude
surprises after clearing because maybe one would only clear to taste..<
This is what I hope, and I think if this was the case it would explain some
of the mysteries that surround the direct carbon processes.
>And speaking of clearing, among the several methods you tried, there was
no hypo clearing agent or sodium sulphite, <
I did not use sod sulphite as I have previously tested sulphite against
metabisulhite and found them very similar, nor have I tested hypo clearing
agent, or Philip Jackson's sodium dithionite, I would like any further
suggestions from other members of the list as I intend to test them all.
>1. The
potassium alum took two hours & by reputation could degrade colour,<
I think it is chrome alum which degrades and gives colour problems ?
>2. the sodium metabisulfite makes you (or anyway me) choke<
I have built a fume cupboard around my photographic processing sink and do
all my pongy chemical mixing in there.
>3. Some people would be antsy handling (or even getting) sulphuric acid.
(And it isn't clear to me that it has any advantage except in gross
over-exposure.)<
This is perfectly understandable, but as you have said on a number of
occasions that there are a lot of very nasty things in the kitchen cupboard
and a 1% sol is very weak.I can give you three main advantages to the use
of this clearing agent :-
1) It is the strongest agent
2) It is the fastest average time in fresh solution 30sec's to 2min's
3) It will get the stain down to almost base white on paper and actual base
white on Synteape or any other impervious substrate
Now these factors may be of no concern, so be it, as Terry says" there
ain't just one way to do it", but the point is this is real information not
just hearsay, the information is there to use if need be.
>So if you'll tell my what your proportions were, somewhere along the line
I'll try the two other clearing baths....<
Please do Judy and if you could cross check my results I would be most obliged
Then you say the "tonal variation [of different clearing] could go a long
way to explaining the apparent fickleness of the processes." You're
talking about .1 density as "explanation" for fickleness? Aside from not
getting the "explanation," I myself would not measure .1 density when I
talk fickle, rather reserving the term (which I rarely apply, assuming
instead a sloppy or careless mistake on my part) for a different order of
magnitude.
I am dyslexic and have problems with language sometimes, as you have noticed :-)
what I mean by fickleness is the fact that I have found the traditional
gum process inconsistent ,I think if we put our hand on our heart, we are
all somewhat careless at times, but not all the time or no real progress
can be made, and a mental slap on the wrist usually does the trick.It was
these inconsistencies over a number of years that caused me to develop the
Fotempera process.It is a totally consistent process, it works exactly the
same time after time.
In 1994 I was invited to take part in a symposium with
David Sopick,and John Pollard at RMIT in Melbourne Australia, we staged a
group exhibition of our work, took part in a public forum, also ran
concurrent workshops over three days,at the end of which we had a
throughput 36 students,all the students who worked with me achieved
finished work whereas only a few managed to produce finished work in David
And Johns classes,, both John and David were working the classic gum
processes whereas I was employing the Fotempera, both my friends David and
John are talented artists, experienced teachers, and skilled practitioners.
it was the process that made the difference.
>One final point: For those who don't want to punch a hole in their
samples, another comparison method is to punch holes in two white cards
and run one along the sample and the other along the grey scale next to
it. You compare the areas exposed by the holes side by side. Not quite as
easy to read perhaps as through-the-sample, but nearly..<..
Also there is a problem with a hole through the sample in that the colour
is difficult to compare to the grey, I got round this by moving the hole
to a grey that just looked light in comparison then to a grey the looked
just dark and then split the difference.I might try a complimentary filter
next time.
cheers pete