Only here can you start talking about TXP and end up with someone talking/speculating/arguing about TMY.
Only here can you start talking about TXP and end up with someone talking/speculating/arguing about TMY.
For what it's worth, all the films under discussion are 'controlled crystal growth' films - it's just that the current TMAX's (and TX/TXP shares a fair bit of technology with them) and Ilford's Delta's & Fuji Acros are somewhat more sophisticated in the way they use different grain structures, which while they may use tabular grains in some emulsion components, cubic grains are also used elsewhere in the structure. There's a number of posts from Ron Mowrey (Photo Engineer) over at APUG in the emulsion making section that covers BW film design history in considerable detail if such things interest you.Originally Posted by axs810
As you said (great contribution!), the pink is... (fact) "in emulsion" sensitizing dye complexed with osmium compounds, but stick to what Ron said... not acutance dyes or other !!!
interneg, I'm not talking about photochemical complexity, but about clear facts.
TMX is a Pink Panther, with a remarkable (fact) and irrefutable pink screen in it, filtering light inside emulsion. I repeat, now this is a fact.
So no doubt (fact) that the remarkable pinky screen contributes to the final (and desired) spectral foodprint, probably (guess) as a controlled parameter.
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PD: Note that "layered dyes" is not "layers of emulsion"... but layers of different dyes around single crystals...
http://www.google.ch/patents/US6361932
IMHO TMX has 2 layers of sensitive emulsion IIRC, and at least the outer one should be of "layered dyes" type...
Last edited by Pere Casals; 6-Jun-2017 at 02:59.
Sorry OP, for the /*off topic*/ about film nature side debate.
Anyway this time it has been productive, at least (speaking about me) I've learned a lot.
I'm not sure about that. Try a portrait with 8x10 TMAX (developed in xtol) and FP4 (developed in rodinal), and contact print them. They'll be very different.
In essence that patent describes the use of a sensitising & acutance dye utilised in a way to maximise sensitivity to light enabling higher speed for a lower grain. In other words a cyanine (panchromatic sensitising) dye & one that isn't. The one that isn't panchro is the acutance dye. It's there to filter out unwanted bits of the spectrum to (amongst other things) enhance sharpness, reduce reflection issues etc. What you are attempting to call a 'screen' may well be an acutance dye.
The pink dye in question - either for green sensitisation or to control sensitivity to green light - seems to not be broken down during processing as easily as most other dyes. It can be removed by a longer wash or by sulfite or by exposure to oxygen. Within the dyes listed in the patent, there are several that would comply with the colour that comes off TMAX or Ilford or many other films. Indeed, several of the dye families mentioned in there have quite a number of intense colours in the pink to purple range that would seem likely candidates. Owing to the manner of the use of these dyes and the greater available surface area in modern controlled crystal growth emulsions, they are likely to be used in larger quantities than in previous generations of films - it's all aimed at making as much of the silver usable as possible & minimising wasted silver in the emulsion.
Given that people have reported similar colours with Ilford films, it seems that the dye family in question is in widespread use.
Indeed. And even if you ran them in the same developer adjusted to the same contrast they'd be different. But that would require him to actually try the materials, rather than adsorbing synthetic fluff from bad simulation programs...
What grain in 8x10 contact copy ??
FP4 vs TMX contact copies may look very different, but not becacuse grain, just realize what is the size of grains.
Last edited by Pere Casals; 6-Jun-2017 at 05:37.
interneg...
I showed you the patent only because you said might be "3 emulsion layers or more", when TMX it is 2 sensitive emulsion layers only... a slow cubic one and a T-grain, I thought your confusion was comming from the "layered dye" concept, that's not about "3 emulsion layers or more", but no... just 2 sensitive layers !
T-grain emulsion layer is pretty pink, it is irrefutable that TMX is in fact a "partial self-screening" emulsion.
It doesn't matter why a color dye is in the sensitive emulsion, if it filters light then self-screening happens.
Still an emulsion may have additional colouring dyes inside that are destroyed during process... but I don't know much about that...
I think I've said all I should about that.
Last edited by Pere Casals; 6-Jun-2017 at 11:01.
We often tell ourselves stories, sometimes we even believe them. And then, once that bridge has been crossed,
we tend to believe the 'evidence' that supports us and dismiss all else. We like being 'right'.
All this blathering, on and on, pages and pages of it, filled with suppositions, logical fallacies,
specious statements presented as 'facts', ad nauseam; what's the point of all this effort?
To suggest that a film has a spectral response?! Alert the press! Design your own emulsion
and see what you get. TMX has a fairly linear response, as much or more than most films.
Millions of images have used it; it's a fine film, one of the best *ever* made,
and I will miss it when it is gone.
But what do you care?
It's not about the 'truth' here, it's about being 'right'. You're tilting at windmills.
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