Re: Dry Dichromate and Gum, was Re: News from APIS

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From: Clay (wcharmon@wt.net)
Date: 07/22/03-08:56:58 PM Z


Hi Sandy:

Also just for clarity's sake, Stuart doesn't claim to have invented the
dry dichromate technique. It was also in some of the old literature,
from what he (Stuart) says. None of the things he is doing is new, in
and of itself, but I believe, (and I'm putting words in his mouth) that
he just wanted to show us his combination of procedures that he has
found to be pretty bomb-proof.( if such a state of grace exists in gum!)

And I totally agree with you about Sam's gum prints. They are really
fine. I want one badly.

Clay

On Tuesday, July 22, 2003, at 09:31 PM, Sandy King wrote:

> Just for the record, Sam Wang has been using dry ammonium dichromate
> for years and years in gum printing, and he makes some of the best gum
> prints I have ever seen, vintage or contemporary. I am pretty sure
> that he described his technique here on the list at some time in the
> past.
>
> From my rough calculation of the gum solution below (guess this is
> from Stuart's talk at APIS?) it appears to be 20% (or even less with
> the pigment added), which is of course well below saturated solution.
> As I recall from Sam's work, his dichromate solution might be even
> weaker than that, and as far as I know he is not using a roller or
> anything like that to coat.
>
>
> So why are folks using saturated solutions of ammonium dichromate if
> it is not necessary?
>
> Sandy King
>
>
>
>
>
>
>
>> Having been a beta-tester of sorts for the whole gum-thing, I'll try
>> to answer where I can.
>>
>>> <Ed said>Gum: For a typical 8x10 print he uses 10 ml of 14 BAUME gum
>>> arabic
>>> and 2 g ammonium dichromate.
>> Yeah, the dry dichromate thing obviously really reduces the water in
>> the solution, and allows some very heavy pigment loads. I am still
>> VERY paranoid about dry dichromate and wear a dust mask and mix over
>> the sink so any spills can be washed away. Remember that you will
>> want to alter the amount of dichromate depending on the contrast and
>> speed you desire in particular coat you want to lay down. More
>> dichromate means faster exposure times and lower contrast. Less
>> dichromate means more contrast and slower exposure times, all other
>> things being equal, which of course they aren't for any given coat
>> will probably also have the variable of pigment color thrown in as
>> well. A test strip is always a good idea if you're uncertain.
>>
>>>
>>> This I found interesting: that he uses dry dichromate. This was
>>> done in
>>> former times, too, and included in that weird patent I posted before
>>> APIS. A
>>> must-try.
>>>
>>> <Ed said>He also adds one drop of Raphael's Miracle
>>> Muck per 2 ml gum (in this case 5 drops) to eliminate flaking.
>> This exact amount doesn't seem to be critical. I use the 'glug'
>> method, since the undiluted Muck is so viscous it is difficult to
>> measure a drop accurately. I use one tipped-over bottle 'glug' per
>> 10ml of gum. Stuart dilutes his 1:1 so it is easier to measure (DOH!
>> of course) Recently, Kerik has eliminated the Muck with no apparent
>> ill effects. This may eventually prove to be just some salt thrown
>> over the shoulder for "good gum luck"
>>
>>>
>>> For some reason, my proportions are different: I have 1 drop per 1
>>> ml of
>>> gum; am I wrong here?
>>
>> 1 drop of Muck diluted 1:1 per ml would be about right. Or 1 drop
>> per 2ml if undiluted. Or one glug per 10ml. Or maybe none at all. And
>> don't forget the Everclear. I have been putting about one dropper
>> "shoot" per 10ml. It really smooths the coating out a lot.
>>>
>>
>>> <Ed said>Coating: Stuart coats gum with a 6 inch foam paint roller.
>>> He
>>> stated that foam rollers are widely reported to not work with gum.
>>>
>>
>> The roller is really something with this technique. You gotta try it.
>>
>> And I must re-iterate what Stuart said in his talk before the
>> inevitable gum war erupts: He is saying his method is ONE way of
>> doing it. Not THE way, or anything like that. We know it works in
>> Saharan Santa Fe, Picturesque Placerville and Humid Houston equally
>> well. It delivers on its promise of big pigment loads that don't
>> flake. If that doesn't suit your style, no worries.
>>
>> Smoothly,
>>
>> Clay
>


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