U of S | Mailing List Archive | alt-photo-process-l | RE: tips for using dry pigment

RE: tips for using dry pigment

You have done well to confuse us with two processes in one parapraph, both using powdered pigments.
 I assume that your observations and issues are different for carbon tissue making and gum printing.
I have used powdered carbon black for both gum printing and carbon tissue making. My secret for carbon tissue making is to add about 0.5cc/liter of emulsion of jet dry (a detergent  that is used here for spotless drying of the dishes in automatic diswashers). I add jet dry to the gelatin mix and pour some in a blender with the carbon powder. Mix it thorugly for a few minutes (don't worry about bubbles) and add the remaining gelatin. The detergent works miracles in terms of dispersing carbon and later allowing bubbles to break.
I use it for mixing gum with carbon black powder, a few drops /100 ml, but find it less necessary.
Hope that helps.
FOr carbon tissue amking
> Date: Tue, 12 May 2009 00:40:07 +0200
> From: phritz-phantom@web.de
> Subject: Re: tips for using dry pigment
> To: alt-photo-process-l@usask.ca
> hello judy.
> i got the P-F issues on friday (that was rather quick). thanks! i've
> been reading like mad since then.
> sugar: i need the sugar to keep the curl out of the carbon tissue. i
> can't go below 60gr/liter. i've tried 40 and it was too little. one time
> i completely forgot the sugar and the result was a tissue that was
> almost unusable because of the curl.
> i've read carbon formulas that called for a lot of strange stuff, honey
> one among them. i got the forumla with sugar from the sandy king article
> on unblinkingeye. i think the sugar is not supposed to do anything
> image-wise, but only keep the tissue flat.
> whoops. i used the wrong word, "brick and mortar" for "pestle and
> mortar". of course i was not grinding it with a brick. i do use
> "grinding" to mix the pigment with the fluid, not to grind the pigment
> finer. i read a little about how it's done in painting and they all used
> a thing like a mortar and pestle to mix it.
> i don't have problems mixing for gum, it's fine after just a little
> mixing with the brush. carbon is different, it's a lot more pigment (7gr
> for 500ml pigmented gelatin solution). when i put the water into the
> mortar, the pigment floats on top at first, then goes into the solution
> while mixing. i thought about adding a dash of alcohol to get rid of the
> surface tension of the water. it would make the process easier and less
> messy at the beginning.
> i have to pre-mix the pigment in a little bit of fluid before adding it
> to the whole batch; mixing it in the 500ml of gelatin would be very
> messy and impractical. so i just mix it in a little bit of water, then
> add it to the whole.
> i still haven't got a stouffer-step wedge, but i just prepared some
> carbon tissue to do the same testing with chart throb (digital step
> wedge and analysis program), i just did with gum printing. so, soon i'll
> be able to say more about that.
> (i could post the scans of my comparsion of 5% vr saturated ammonium
> dichromate, if interesting to someone and not a complete bore fest.
> saturated is highly superior, step-wise. but i might try and use 5% for
> my shadow exposures)
> phritz
> Judy Seigel schrieb:
> >
> > Phritz, I don't suggest adding so much as subtracting. Have you
> > done a variables test without the sugar? I found that it not only
> > didn't improve, it disimproved... But you don't say how you're judging
> > results. Have you got a 21-step or other measured density
> > transparency? Have you tested this mix against anything else?
> >
> > For what it's worth, unless you're digging your own dry pigment out of
> > your own hole in the ground, it comes from the store as fine as you
> > can possibly use, which is to say, more finely ground than you could
> > improve on if you "ground" it for the next millenium.
> >
> > I got this directly from founder of Golden pigments years ago at a
> > College Art Association conference. The reason you "grind" is to be
> > sure you've got every particle surrounded by gum arabic (or linseed
> > oil if you're doing oil paint, etc.) so it won't clump when you add
> > the other ingredients.
> >
> > That sugar business is pure nonsense, somebody's bright idea after
> > sucking up too many lollipops. (Test it if you don't believe me, but
> > if you haven't got a 21-step or other measured density guide,,,,,,,
> > how are you going to test ???? Nowadays folks make a digital step
> > guide... which I'm not fond of because I trust the 21-step with its
> > known density range more, but handled rightly it should be fine,
> > surely better than guessing.)
> >
> >
> > Presumably you have a mortar & pestle. Skip the pestle, put a measured
> > amount of dry pigment into the mortar than add measured am't of gum
> > arabic, thinned with a measured amount water. (Choose your starting
> > amounts depending on thickness of gum, am't of pigment, desired
> > thickness of emulsion, etc., but don't add enough liquid so anything
> > "floats"!!!) Then you brush briskly with a wretched old round bristle
> > brush, and I do mean bristles. The one I use says Robert Rebetez Basel
> > #270 on it, probably because it's 270 years old. The bristles are
> > stiff & the ratty old thing comes to a point, sort of, but it's ugly
> > and horrible & stiff and perfect for the job... Just scrunch the mix
> > around in that white mortar bowl til it seems smooth to the eye, maybe
> > 3 minutes, depending on volume, then scrunch another minute or so, add
> > about half the volume of saturated ammonium dichromate solution & coat
> > some paper to test.
> >
> > If you don't have a mortar, put the ingredients together in a cup,
> > stir well, then empty onto a sheet of heavy glass or an enamelled
> > butcher's tray-- that's a flat tray about 8x12 inches with low rim
> > around it -- enough to keep your liquid from spilling over, but not
> > high enough to interfere with smooching the stuff around with a
> > pallette knife until it's amalgamated... maybe 3 minutes, depending on
> > volume.
> >
> > The amounts above are purely arbitrary depending on your volume of
> > pigment and its fluff, or density, plus the viscosity of your gum, as
> > well of course as your style of printing. The important thing is to
> > measure what you add and then modify amounts accordingly. I note
> > however that this is for gum printing. If you're doing this for
> > carbon printing, I don 't have a clue -- EXCEPT I've probably read or
> > skimmed 90% of the classic carbon formulas. I don't recall any that
> > called for sugar. Who is this sugar advisor? A Cuban?
> >
> > Oh, and that grinding with a brick stuff is nonsense for any process.
> > (Unless you want bits of brick as pigment, which could have a nice
> > texture.)
> >
> > BTW, the pigment should be neither sinking to the bottom nor floating
> > on the top, rather an even amalgamation, like, say, chocolate syrup.
> > But come to think of it, what process are you adding dissolved gelatin
> > to? Gelatin at room temperature tends to set ... then what do you do
> > with it? Is this some special gelatin process? In which case, I never
> > heard of it, so ignore everything I've said above.
> >
> > cheers,
> >
> > Judy
> >
> >
> >
> On Sun, 10 May 2009, phritz-phantom@web.de wrote:
> > i mostly use dry pigment for all my alternative processes. i started
> > using it, because of a misconception that most alternative photo
> > printers prefer it. later i learned that it just the opposite is the
> > case. but actually i want to keep using it. it's way cheaper (i can
> > buy 80gr of lamp black - which lasts a long time - for the price of on
> > 15ml tube) and i already bought about ten jars. so far i haven't had
> > any problems with printing gum (i put a little bit in a jar, mix it
> > with gum and dichromate with a brush - no problems, no specks at all).
> > but sometimes with carbon i get these specks (i'm not really sure if
> > it's the pigment or the sugar in the mix (i use a rather high sugar
> > content). i filter the carbon solution through a piece of nylon (? -
> > the stuff women's stockings are made of), but still - mostly with the
> > last tissue of the batch; of course the specks go down to the bottom.
> > my normal procedure is to first mix the pigment with a brush and a
> > dash of water, then grind it with a brick and mortar, then put it into
> > the gelatine + sugar solution. i tried grinding the pigment in a
> > little bit of gelatine solution, but using water was better. i once
> > put a little big of alcohol (it's an old bottle labeled
> > "brennspiritus" ("ethanol") i inherited from my grandfather, but i
> > don't really know which kind of alcohol it really is, it's ages old)
> > into the pigment mix and this had the good effect that the pigment
> > sinks to the bottom, instead of swimming on top of the water. it makes
> > the mixing a lot easier. what else could i add that would make the
> > mixing and grinding easier. i haven't added any alcohol or whatever to
> > my pigment mixes for alt. processes so far, because i'm afraid it
> > could interfere with the process.

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