Re: Rethinking pigment stain

You might have a point there, in that 'global insolubilization' is a
mouthful and not very graceful. For a Latin-derived language speaker
as I am right now, this sounds more naturally. Also, it is an
accepted and frequently used term, not at all comparable to
'eligibilize' which is rather artificial, don't you agree? But if
you'd care to propose another better-sounding term to mean 'the
action of getting insoluble', fine. I simply cannot think of one.

Be it as it may, in normal speech we still will be using 'fog', I hope :-)

As to 'global'. I meant it as a spatial concept, in that the
insolubilization happens in all the layer. I did not mean that the
insolubilization should be complete.

But you give examples of what would be a spatially partial
insolubilization due to accidental presence of light (and excuse the
clumsy sentence!). In your example of the ray of light shining
through the window it could be said that you were simply exposing
accidentally to a different subject.

To make the concept clearer: if I leave the shutter accidentally open
in my pinhole camera, what I have later is an unintended exposition
or fog? Not easy to say, in my opinion. It depends. If I realize what
has happened and just develop the negative I have an image. If I,
without realizing that an exposition has been made, make another
superposed exposition, I could call the first one fog.

But I see what you mean. Actually _every_ fogging agent can be
applied only to a region of the gum layer and not to the whole. The
only exception would be the use, mentioned by Christine, of some
pigment that reacts with the dichromate.

This could be taken as a probably valid objection against the use of
'global'. Having to explain 'global in the domain of actuation of the
fogging agent' each time is horrible, even if it is true. I'll think
it over some more ...

About your definition now. I don't find it too satisfactory either.
But first, sorry for having said 'image-forming'. Just a slip, I know
you said 'image-related.

1. The inadvertence or lack of intentionality is unimportant. Fog
happens under certain conditions, that is all. We generally do not
seek it as such, but we might, for example for experimental or
research purposes. In this case, it would be 'intentional' fog.

2. If fog is or is 'not related to the image that is being
intentionally printed' is also irrelevant. Fog is generally speaking
independent of any image that we would be eventually making on the
same layer. There are exceptions to this as some image-forming
techniques could be fog-producing. Overexposure, too hot an illuminator ...

To explain this point: lets say that I prepare a layer of dichromated
gum and for some reason forget it in some drawer. After a week I find
the coated sheet of paper. Do I use it for exposing an image?
Normally no because my experience tells me that it is probably
fogged. That is to say, I know that some degree of insolubilization
(or crosslinking, if you prefer) has happened in the layer without
having to expose and develop an image.

Just some thoughts, as usual, for what it's worth...

Tom Sobota
Madrid Spain

At 03:49 15/12/2005, you wrote:
>On Dec 14, 2005, at 1:36 PM, Tom Sobota wrote:
>
>>I was commenting on Dave's opinion that '"fog" is a misleading term',
>>which implies that we pretty much _don't_ all agree on what fog is.
>
>Fair enough; I was reading Dave's remark to mean simply that he
>didn't think fog was often encountered in usual practice with gum, a
>remark I agree with, but yours is a more literal and for all I know
>more accurate reading.
>
>>
>>As my use of "global insolubilization", it means the following:
>
>I didn't say I didn't understand it; "global insolubilization"
>pretty much defines itself. I just said I found it an awkward
>mouthful, meaning not a very graceful phrase, and I wouldn't be
>likely to use that particular verbal construction myself, as it
>seems ugly to me in a prosodic sense, quite apart from its meaning,
>much like the bureaucratic words like "eligibilize" etc.
>
> But on reflection, I find I don't even agree with the phrase as a
> good definition for fog. While there are some types of fog, such as
> the dark reaction, that will probably always present as a global
> insolubilization, there's no particular reason why inadvertent
> exposure can't affect a part of the coating without the entire
> thing being fogged, or that it can't crosslink enough of the gum to
> partially harden the coating without rendering it completely insoluble.
>
>I'm going to make a liar out of myself now by recalling a second
>example of fog from my own experience, after I said I'd only seen it
>once, but one can't remember everything all the time, especially
>when you're as old as I am and have as many things to remember as I
>have. At any rate, one time a stray ray of weak sunshine found its
>way between the pine trees and the garage and the guest cottage and
>the house into the studio to cast onto the drying table a dim shadow
>of the windowframe, so dim I didn't even notice it as I was drying
>the coating. But it had already printed itself into the coating, and
>spoiled the subsequent print. I would call this fog. It was
>inadvertent formation of crosslinked gum, but it certainly wasn't
>global insolubilization (not only did it only affect the parts of
>the coating that the sunlight actually fell on, but the intentional
>print printed on top of it, so the gum obviously wasn't completely
>insolubilized, even in the areas where the coating was fogged.
>
>So I'm going to stick with my wording, not only because I like the
>sound of it better, but because it means exactly what I mean by fog,
>and "global insolubilization" does not. But perhaps I should
>specify, though it seems to me it should go without saying, that I
>am not imposing my definition on you or anyone else, just telling
>you why it's the one I will use myself, personally.
>
>>
>>
>>This is the term I prefer, but I'm not imposing it upon anyone,
>>so if you want to say "inadvertent (meaning non image-related)
>>formation of crosslinked gum" instead of "global insolubilization",
>>that's just fine with me. I would only object on the use of 'inadvertent'
>>as a synonymy for 'not image-forming'. But hey ...
>
>Actually, I said "not image-related" rather than "not image-forming."
>inadvertent means "not intentional," meaning not related to the
>image that is being intentionally printed. But fog can certainly be
>image-forming, as in the case of the image of the shadow of the
>windowframe that printed itself perfectly onto my print.
>
>>
>>Again, whether fog happens more or less frequently in actual
>>practice is not an impediment for having a definition for it, in my
>>opinion.
>
>I agree; earlier today I thought we all pretty much agreed on a
>definition, but now I see that we don't.
>
>Katharine
>
>
>>
>>At 17:43 14/12/2005, you wrote:
>>>I think we pretty much agree on what fog is, although I would
>>>never use the phrase "global insolubilization;" that seems a
>>>rather awkward mouthful to me. I'll continue to use the phrase
>>>I've been using; to me fog is the inadvertent (meaning non
>>>image-related) formation of
>>>crosslinked gum, and, as I said in my response to Joe's lexicon
>>>last week or whenever that was, in my mind it includes the dark
>>>reaction. I don't know about the "continuing reaction" I've never
>>>seen that myself.
>>>
>>> I thought Dave's point was, how often do we ever see fog in
>>> actual practice? I've only seen it once, when I left a coated
>>> paper sitting by a window and went off to get something. And I've
>>> only seen fog in the form of the dark reaction once, when
>>> I deliberately left coated paper in the dark to see if it would
>>> happen (it did), but I've never seen it in practice, because I
>>> always coat and dry one paper at a time and expose immediately.
>>>Katharine
>>>
>>>
>>>
>>>On Dec 14, 2005, at 7:08 AM, Christina Z. Anderson wrote:
>>>
>>>>Right on, Tom,
>>>>
>>>>fog = global insolubilization of the gum layer...
>>>>
>>>>I'll add to your list one thing they used to say but I have never found to
>>>>be true is they used to say certain pigments produced as they termed it
>>>>"spontaneous insolubilization of the gum".
>>>>
>>>>I could say that when I was doing 8 large gums at once down in South
>>>>Carolina where the humidity was higher, the last print to go into the water
>>>>would take longer development to remove nonimage "fog". Fog, up to a
>>>>certain point in gum practice, usually doesn't make too much difference
>>>>because it is removable, unlike silver gelatin.
>>>>
>>>>Does this fog, then, form an umbrella over the two terms of "dark reaction"
>>>>and "continuing action"? Because both result in global, non-image
>>>>insolubilization. In other words, back in "the day" (1800's-1900's) they
>>>>didn't term it fog in the first place but used these two terms to describe
>>>>this global insolubilization.
>>>>chris
>>>>
>>>>>It all depends on how you define 'fog'. To me, fog is a global
>>>>>hardening or insolubilization of the gum-dichromate layer which
>>>>>does not contribute to the formation of an image.
>>>>>
>>>>>It can be produced by any (or a sum of) several causes, among which
>>>>>accidental exposure to light too, of course. Others are heat, exposure
>>>>>to chemicals, and the simple passing of time. Surely others.
>>>>>
>>>>>The normal exposure to light of a layer of dichromated gum under
>>>>>a negative produces a hardening which is not physically different
>>>>>from a fog-producing exposure to light, but it produces an usable image
>>>>>since it is not global but rather differential. So we don't call it fog.
>>>>>
>>>>>This loose definition of fog could be applied to silver-gelatin emulsions
>>>>>too, actually.
>>>>>
>>>>>Pigment stain is different, and perhaps unique to gum, carbon and
>>>>>other processes using finely ground particles of pigment.
>>>>>
>>>>>But dichromate stain has a sort-of analogue in silver-gelatin emulsions
>>>>>when you develop with pyrogallol or pyrocatechol, for example, which
>>>>>also produce stain. This stain contributes to the image, however, because
>>>>>it is in the negative and not in the positive.
>>>>>
>>>>>If you want to see fog in gum, coat a paper and keep it in the dark for a
>>>>>week or two in a warm place. Then develop side by side with a
>>>>>just-prepared emulsion. The relative darkening of the older coat should
>>>>>be evident.
>>>>>
>>>>>Tom Sobota
>>>>>Madrid, Spain
>>>>>
>>>>>
>>>>>At 03:38 14/12/2005, you wrote:
>>>>>>I don't know all the details regarding that past discussion, but I think
>>>>>>"fog" is a misleading term. I consider fog to be accidental exposure,
>>>>>>e.g.
>>>>>>someone opens the back of a 35mm camera and the film gets "fogged".
>>>>>>Perhaps
>>>>>>gum paper can get fogged from ambient light levels being too high in the
>>>>>>darkroom, but I've never had that problem.
>>>>>>
>>>>>>Dave Rose
>>>>>>Powell, Wyoming
>>>>>>
>>>>>>----- Original Message -----
>>>>>>From: "Katharine Thayer" <kthayer@pacifier.com>
>>>>>>To: "alt photo" <alt-photo-process-l@sask.usask.ca>
>>>>>>Sent: Tuesday, December 13, 2005 12:16 PM
>>>>>>Subject: Rethinking pigment stain
>>>>>>
>>>>>>
>>>>>> > Hi gum printers,
>>>>>> > Because for most of my gum printing career I've printed on unsized
>>>>>> > paper, I developed a definition of pigment stain that I realize now
>>>>>> > probably applies mainly, if not exclusively, to printing on unsized
>>>>>> > paper. My definition required that in order for something
>>>>>> to be called
>>>>>> > pigment stain, the pigment had to penetrate the paper and be
>>>>>> indelible.
>>>>>> > And in my experience, when pigment stain occurred, it occurred
>>>>>> > immediately when the coating was applied; if the pigment
>>>>>> was excessive
>>>>>> > in relation to the gum, it would stain the paper immediately on
>>>>>> > application.
>>>>>> >
>>>>>> > The tonal inversion thing made me rethink that idea, as I
>>>>>> said a couple
>>>>>> > of days ago, and after doing some experiments with sized and unsized
>>>>>> > paper, I've decided I need a more inclusive definition that
>>>>>> > incorporates what happens on sized paper, or maybe two
>>>>>> different terms;
>>>>>> > I haven't decided yet for sure.
>>>>>> >
>>>>>> > A more inclusive definition for "pigment stain" would say that pigment
>>>>>> > stain is whenever you get pigment in places where it shouldn't be,
>>>>>> > such as in unexposed areas of an image or step print. Whether or not
>>>>>> > that out-of-place pigment forms an indelible *stain* will be
>>>>>> a function
>>>>>> > of how well the paper is sized. On sized paper, this
>>>>>> "stain" will wipe
>>>>>> > off easily, whereas on unsized paper it will be indelible, but in
>>>>>> > either case, you've got pigment you don't want in areas that should be
>>>>>> > very light or paper white, hence: stain.
>>>>>> >
>>>>>> > One problem with this more inclusive definition is that it doesn't
>>>>>> > distinguish between stain and fog. Someone referred recently to a
>>>>>> > discussion from last summer where Mark showed a gum test print where
>>>>>> > there was color on areas where the print should have been paper white.
>>>>>> > I called that stain, and was told that it was fog. I conceded the
>>>>>> > point; when told that it could be wiped off the paper I assumed (given
>>>>>> > my then understanding of stain) that it couldn't possibly be stain and
>>>>>> > must be fog, although I didn't have a clear understanding of
>>>>>> what could
>>>>>> > have caused the fog. And when that was brought up recently, I
>>>>>> > acknowledged I'd been wrong when I'd called it stain. But now that I
>>>>>> > have seen for myself that pigment stain can also be easily wiped off
>>>>>> > sized paper, (while still wet, of course) I'm not sure I know how to
>>>>>> > tell the difference between stain and fog on sized paper.
>>>>>> >
>>>>>> > They are of course different in substance, because what I would call
>>>>>> > "pigment stain" is just pigment, since it occurs in areas where no
>>>>>> > exposure, and therefore no formation of crosslinked gum, has occurred,
>>>>>> > whereas fog, in my opinion, would involve the formation of crosslinked
>>>>>> > gum.
>>>>>> >
>>>>>> > On unsized paper, excess pigment impregnates the paper as stain, and
>>>>>> > that's why it stays with the paper rather than dissolving
>>>>>> away with the
>>>>>> > dichromate and soluble gum from unexposed areas. But on sized paper,
>>>>>> > even though the pigment isn't held in the paper as stain, or in
>>>>>> > crosslinked gum as "tone" it still remains on the paper in unexposed
>>>>>> > areas, as seen in the examples of "tonal inversion." This is
>>>>>> > interesting, but puzzling, to me. At any rate, I've satisfied myself,
>>>>>> > by cutting coated papers in half and exposing one side and putting the
>>>>>> > other side directly into water, that the "pigment stain" is the same
>>>>>> > on unexposed areas of exposed coatings as it is on
>>>>>> completely unexposed
>>>>>> > paper, whether sized or unsized, which makes me even more confident
>>>>>> > that the effect has nothing to do with exposure, heat or
>>>>>> anything else
>>>>>> > related to the exposure itself, but is simply pigment stain.
>>>>>> >
>>>>>> > Thoughts, anyone? I will soon be revising my page on stain, lord
>>>>>> > willing and the creek don't rise, to reflect the evolution of my
>>>>>> > thinking on this topic.
>>>>>> > Katharine
>>>>>> >
>>>>>> >
>>>>>
>>
Received on Thu Dec 15 07:47:53 2005