NER - did you know that XTOL generates a stain? It does, bleach some XTOL processed film and you will see a very faint magenta stain. It's not enough to have a significant effect, but it is visible.
Helen B said:Norman wrote:
"...I defer to Mees, Tull, Neblette, Hauff, Bogisch, Lumiere, Andresen, Haist and researchers of similar reputation whose reports were both authoritative and accurate, and did not - to the best of my current knowledge - mention anything about hydroquinone image stain. ..." My emphasis.
Before I quote something else, I'd just like to say two things:
-I'd trust the guys here who say that hydroquinone forms a stain image even if I didn't already know it, and
-few of the standard texts (or at least those I have) go into much detail on stain images, if they mention it at all, but they do cover tanning. Tanning and staining may not be the same, but they are similar, and if the developer oxidation product is coloured then there is likely to be a link between tanning and the formation of a stain image.
OK, so on to L P Clerc's Photography Theory and Practice, 1971 edition revised by R. E. Jacobson, Vol 4, Monochrome Processing:
"573. Oxidation Products of Developers; Tanning; Secondary Images.
The quinonoid oxidation products of developers that are formed in the absence of sulphite, or in the presence of very low concentration of sulphite, are deposited in the gelatine at the site of development, and in a quantity proportional to the amount of silver halide reduced. Usually they polymerize, giving rise to coloured, tanning substances of the nature of humic acids, whose exact constitution is unknown.
After removing the silver image ... a yellow or brown secondary image remains, which, though it may not appear very intense to the eye, can give acceptable prints on high contrast paper because of its absorbtion of actinic light. The following table (Lumière and Seyewetz, 1928) shows the colour of the secondary image obtained in various developers, its relative intensity and the concentration of sulphite necessary to prevent its formation.
Developer -- colour -- relative intensity -- sulphite g/litre
Pyro -- yellow-orange -- 10 -- 11
Catechol -- black -- 10 -- 6
Hydroquinone -- yellow-brown -- 10 -- 2
Chlorhydroquinone -- yellow-brown -- 10 -- 2
Amidol -- reddish-brown -- 8 -- 2
p-Aminophenol -- brownish-black -- 3 -- 2
Metol -- brownish-black -- 2 -- 1
PPD -- Grey -- 1 -- 0
Glycin -- None."
Best,
Helen
psvensson said:Kirk, he's going to ask you where you read that, so hit the books!
NER said:Why is asking for verification of a statement so unusual and a cause for ridicule?
psvensson said:Yes, there is. I don't have the issue in front of me, but he does say something like "Bet you didn't know hydroquinone can be a staining developer." He was right about that!srs5694 said:Perhaps there's something more explicit in the body text somewhere, or in another issue.
Helen B said:" ... Tanning and staining may not be the same, ... "
One and the same I'd say.
" .... if the developer oxidation product is coloured then there is
likely a link between tanning and the formation of a stain image."
The PRODUCT of the reaction TWIXT the oxidation product and
gelatin is a colored, tanned, gelatin.
"L P Clerc's ... and in a quantity proportional to the amount of
silver halide reduced. ... they polymerize, giving rise to coloured,
tanning substances of the nature of humic acids, ... "
So, there it is from L P Clerc; tanned gelatins of various
colors are the result of a reaction twixt the developer oxidation
products and the gelatin. And below some more from Mr. Clerc.
"Developer - colour - relative intensity - sulphite g/litre
Pyro -- yellow-orange -- 10 -- 11
Catechol -- black -- 10 -- 6
Hydroquinone -- yellow-brown -- 10 -- 2
Chlorhydroquinone -- yellow-brown -- 10 -- 2
Amidol -- reddish-brown -- 8 -- 2
p-Aminophenol -- brownish-black -- 3 -- 2
Metol -- brownish-black -- 2 -- 1
PPD -- Grey -- 1 -- 0
Glycin -- None."
Best, Helen
I should have mentioned that some lith developers depend on the reaction between sulfite and formaldehyde to produce NaOH in the working solution. These are two part developers. The sulfite preserves the hydroquinone in one bath. The formaldehyde is added at time of use. The amount of excess sulfite is probably enough to prevent staining.gainer said:I don't recall seeing any formulas for MQ or PQ lith developers. Hydroquinone substituted for catechol in Pyrocat HD will produce a stain image. It is different in color, as the previously posted information says. Sandy King does not find the color as effective for his purposes as catechol.
Hydroquinone, catechol or pyro in TEA can make a single solution staining developer stock solution. The pH won't be high enough to make a lith developer. I think maybe the high silver contrast of lithography keeps whatever stain image there might be from showing.
Gerald Koch said:There is nothing in Xtol to cause a stain image to form. The oxidation products of isoascorbic acid are colorless and more importantly water soluble. If you are seeing a slight magenta stain then this is a small amount of antihalation dye that has not been washed from the film. The oxidation products of Dimezone-S (the other developing agent in Xtol) are also water soluble.
Tom Hoskinson said:The lith developer may very well be tanning and staining - or it may be that the design of the lith film emulsion prevents/suppresses it. In any case, Bleaching the silver out after development and fixing seems like a good way to tell.
Kirk Keyes said:Helen, Ole, you guys make good points about the "hardening" of the processed areas with greater optical density possibly making it harder to wash out the dye, whether the dye is antihalation, sensitizing, or other. Not a true tanning or staining process, but one that results in a "stain" nonetheless.
I haven't checked with other non-staining developer/film combinations so I can't say this behavior is unique to the XTOL. Perhaps someone else here has?
gainer said:"Hydroquinone, catechol or pyro in TEA can make a single
solution staining developer stock solution.
The pH won't be high enough to make a lith developer."
That is TEA won't make a lith developer of hydroquinone .
Hydroquinone only, of all the usual agents, exhibits
the lith phenomena. BUT TEA MAY!
"I think maybe the high silver contrast of lithography keeps
whatever stain image there might be from showing."
High contrast is not the objective of many who use lith
chemistry. Tan and lith at the same time. How could that
be? The silver halides, gelatin, and chemical products of
reduction are all in intimate contact. Sulfite levels are
at the low needed for tanning and lithing. Dan
dancqu High contrast is not the objective of many who use lith chemistry. Tan and lith at the same time. How could that be? The silver halides said:I have to say what my branch head once said to me. I understand all your words, but I don't understand your sentences. I'm saying this with a big grin on my ugly mug, so don't get upset.
When are those things not in intimate contact? What sulfite levels are we talking about? It takes only about an equal amount of sulfite as hydroquinone to eliminate or at least diminish greatly the staining action of hydroquinone. It takes a whole lot more to get rid of the pyro stain.
We don't always use our potions the way they were intended to be used, but the way they were intended to be used puts some limitations on how we can misuse them. It is difficult to use the lith developers I know of without incurring infectious development. Even Rodinal shows some of those symptoms.
Now I can't remember what I was about to say.
gainer said:When are those things not in intimate contact?
What sulfite levels are we talking about?
gainer said:"I'll check again, but I'm pretty sure you can get a stained silver
image with just hydroquinone and TEA in water. No sulfite required."
Perhaps so. Tests would need be done. If that combination will
tan then it should lith. We're talking Hydroquinone, the ONE
that will tan and lith.
Having given it some thought I'm quite sure that it must be the
semiquinone which does the tanning AND the lithing. Also the
lith phenomenon for the most part follows the tanning.
If sulfite levels are more than very little the formation of quinone
is blocked. In that case, the hydroquinone - quinone reaction
does not take place and there is no exponitial increase
in semiquinone.
"I'm also pretty sure that you won't get high enough contrast to
call it a lith developer. If you then add some paraformaldehyde, the
pH will go way up because of its reaction with sulfite. A lot of fog
will result unless you add two or three bunches of bromide. I'm
speculating somewhat, but the formula I got for "extreme
contrast films" from the 1941 War Department Technical
Manual on Basic Photography is:
water at 125 F.....................................................64 ounces
sodium sulfite (des.)..............................................4 ounces
Trioxymethylene (paraformaldehyde).........................1 ounce
Potassium metabisulfite..........................................150 grains
Boric acid crystals.................................................1 ounce
Hydroquinone........................................................3 ounces
Potassium bromide.................................................90 grains
Water to make 1 gallon
I think there is a Kodak lith developer with these ingredients
but kept in two parts until use. D-8 maybe?"
Once again Mr. Gainer: High contrast is not the objective of many
who use lith chemistry. Full gray scale, pictorial, prints are being
made by at least a few using that chemistry.
The lith developer I compounded by chance, I found later, was of
the Wall's Normal Hydroquinone type; HQ + SO3 + CO3. There are
several formulas for lith developers which have only those three
chemicals plus bromide. Ansco adds a bit of citric acid. Dan
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