From: Stuart W Melvin (swmelvin@earthlink.net)
Date: 07/25/03-09:42:59 AM Z
Ahhhhhhhh.....How refreshing to see fresh info that addresses "ease of
operation" issues. Sounds like you may have this down to a science that also
allows you to pour, coat, and get on with your life as opposed to gathering
around scales, graduates, and teaspoons for each application of emulsion as
the minutes mount. Seems the next logical step here at home is also to apply
some of my observations to personal preference in compounding mixtures ahead
of time to facilitate production of images rather than production of
emulsions.
Thanks Sam,
Stuart
-----Original Message-----
From: stwang1@bellsouth.net [mailto:stwang1@bellsouth.net]
Sent: Thursday, July 24, 2003 10:48 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Re: Dry Dichromate and Gum, was Re: News from APIS
Hi Dave,
If I may jump in here, here is my way of using dry ammonium dichromate: I
add water to
gum to achieve the viscosity I need, add pigment till the color looks right,
THEN add the
required amount of dichromate powder. This way the viscosity and
concentration of
sensitizer are dealt with separately, and it will let me SEE how much
pigment I need to
put in. I understand this is a slightly different procedure as that used by
Stuart.
Another reason is that I prefer to use minimum amount of dichromate to do
the job. I
believe I use about 1/8 of what many others do. Yes, that means I need to
use it with
negatives of a lower density range (lower contrast), not a bad thing since
that means I
can print my negatives on the cheaper overhead transparency films (as
compared to
Pictorico).
Yet another benefit from the lower amount of dichromate is that less is
dumped down the
drain (and damage the environment).
On you question on applying gum by air spray, yes, it works just fine.
However, I would
strongly advise not to spray liquid gum WITH dichromate mixed in. Even with
just gum, I
would wear proper mask and eye protection.
I believe I have mentioned all of the above before, but perhaps no one
noticed.
Sam Wang
>
> From: Dave Rose <cactuscowboy@bresnan.net>
> Date: 2003/07/24 Thu PM 09:36:40 EDT
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Dry Dichromate and Gum, was Re: News from APIS
>
> Greetings from Big Wonderful Wyoming,
>
> As I'd surmised, the "dry dichro" technique appears to be another way of
> controlling gum/dichromate/water ratios on a batch to batch basis. I've
not
> actually tried "dry dichro", but I have to believe that the same results
can
> be had with "wet dichro". Whether you initially mix dichromate powder
into
> gum or water should make no difference, assuming the final mixes are the
> same. Are we not talking about different methods to achieve the same end
> result?
>
> Thank you Katherine for posting the link to my gallery on the
> alternativephotography site. Here it is again:
> http://www.alternativephotography.com/dave_rose.html
>
> Although some of my gum exposures are made with saturated solutions of AD
or
> PD mixed 1:1 with gum (the 'traditional' formula), I'll often vary the
> strength of the sensitizer solution and/or the ratio of sensitizer to gum
as
> need dictates. I think we can all agree that varying the ratios between
> gum/pigment/dichromate/water has a significant impact on the results.
> Utilizing the flexibility of the gum process to it's fullest advantage and
> practicing superb technique can result in beautiful and finely detailed
> prints.
>
> While viscosity of the emulsion does affect its application, I believe
that
> expertise in brushing (or rolling) the emulsion onto the paper is more
> important in achieving "extremely smooth coatings". If a thick, gum-heavy
> emulsion is easier for some printers to work with, that's fine. I use
> gum/sensitizer ratios ranging from 2:1 to 1:2. More often than not, the
> coating is very smooth and even whatever the ratio used. I'm using wide
> Hake brushes. I'm curious to know if anyone out there has tried using a
> paint spray gun and air compressor to apply gum emulsion?
>
> Sorry if I ruffled a few feathers with my post expressing annoyance at
what
> I perceived to be unwarranted "hype" over so-called "new" gum processes.
> Excellent gum prints have been made for many years by dozens/hundreds? of
> talented photographers. Alphonse Louis Poitevin observed the principle of
> light acting upon chromated colloids in 1855. John Pouncy is credited
with
> developing the gum process around 1856. Gum over platinum was being done
> 100 years ago. Study the history of photography. Certainly techniques
can
> be refined and improved upon (as demonstrated by Stuart Melvin), but
> ultimately the gum process remains much as it was during the past. Had
> there not been such a plethora of soft, fuzzy and romantic gum prints made
> during the heyday of pictorialism, gum might not have its undeserved
> reputation as a low-resolution and muddy process. Can you imagine what
> Weston and Adams might have done with gum printing during the F64 era?
>
> As always, the discussions here about gum printing have been entertaining
> and very informative. Welcome to the list Stuart, glad to have you join
us.
>
> Best regards,
> Dave Rose
> Powell, Wyoming
This archive was generated by hypermail 2.1.5 : 08/07/03-03:34:50 PM Z CST