afraid of opening another can of worms.
Also heard it's quite poisonous.
afraid of opening another can of worms.Why?
Stand indeed increases emulsion speed
For smaller formats, it is best done not as pure "Stand" but rather "semi-stand"
Yes. You got that right. Magical powers.p.s. Stand Magical powers?
Of course I did. RereadExcuse me ericdan
First of all, I do not see the relationship between this thread title (Stand) with your OP test (Semi) and the conclusions thereof (Stand) ... much less judging a contact sheet.
Second ...
That is mistaken for a number of reasons.
And finally, you do not mention if the "grain" comparation with Xtol it is also with a Stand (or Semi) development, if not so, no offense but do not mix appless with oranges.
Thank you for sharing anyway.
Best
I am afraid of pyrocat
Of course I did. Reread
What are these insoluble bromide compounds that settle at the bottom?You're right. However development by-products like bromide as they are released will settle to the bottom where they will cause bromide drag and other problems. Stand development is a bit like the forward pass in football. Several outcomes are possible but all but one are undesirable.
What are these insoluble bromide compounds that settle at the bottom?
Yep. I have used XTOL for last 15 years, before that HC110, D76, Microdol-X. All give great results when you follow the book with a steady reliable thermometer. I remember D-23 was all the craze in the mid 70's. Now, All this foolishness of instant coffee, etc.After years of trying all the chatted about techniques (and basically chasing magic bullets), I'm back to some pretty basic techniques. Different off the shelf developers, some zone techniques, but no alternative development methods. Just good solid process with the same materials and consistency above all else yields the best results IMO.
What are these insoluble bromide compounds that settle at the bottom?
Stand development did work with the old thick emulsion films like super XX . Today ...
The problem with bromide drag is bromide and iodide ions are released into the solution. In the absence of agitation these ions remain close to the film surface and are pulled by gravity toward the bottom of the tank. This seems to ...
Hi Martin,
Bromide drag is a well-known phenomenon, going back many decades. Google finds 345,000 references.
It shows up as streaks of lesser density, running vertically (based on how the film is oriented in the tank).
It only occurs with static tank processing, not with trays or rotating tanks.
I've only seen it on other peoples' film at the photo club, never on my own film because I always agitate.
- Leigh
The problem with bromide drag is bromide and iodide ions are released into the solution. In the absence of agitation these ions remain close to the film surface and are pulled by gravity toward the bottom of the tank. This seems to imply a novel way of separating ions based on their relative density. A developer is an aqueous solution and this separation does not occur. Otherwise, the lightest ions, hydrogen, sodium and potassium would remain at the top and you'd end up with a voltaic cell.
If bromide drag does occur, I cannot believe the proposed mechanics.
I am not saying that the developer solution remains homogenous, but that local concentrations of ions are not affected significantly by gravity. In non-agitated solutions they are slowly mixed by diffusion and in any direction. There is no gravitational separation of the various ions or covalent molecules as a function of their mass. Many developers contain small amounts of bromide. Does this bromide settle at the bottom of the storage bottle? Bromide drag should radiate in all directions from the local point of occurrence and not just downwards.When the bromide and iodide ions are released the developer is not longer a homogeneous solution. Therefore gravity can play a part.
Oh mate, if you come on here and express any opinion whatsoever, someone will find a reason to disagree violently with you.I am new to APUG and am trying hard not to be controversial
Do a google on "solution diffusion gravity"Oh mate, if you come on here and express any opinion whatsoever, someone will find a reason to disagree violently with you.
(However, in general, I am always inclined to trust Gerald's statements about chemistry)
When the bromide and iodide ions are released the developer is not longer a homogeneous solution. Therefore gravity can play a part.
Note that halides released from the emulsion are not necessarily what cause the streaking. It depends on the developer formulation but the streaking/mottle can also be caused by developer oxidation products.
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