Lachlan Young
Member
Lachlan, Lachlan...
Look, a DIY emulsion has many technical limitations, one of the limitations is that, while you may increase the speed of the emulsion, latitude won't increase what we may desire, if you blend two or more DIY emulsions of different speeds you in fact increase the resulting latitude, this is the reason why we may mix several DIY emulsions.
Another reason to blend emulsions if making a variable contrast emulsion for photopaper, you mix ortho emulsions with a raw blue sensitive (color blind) emulsions to coat paper or to print on glass. IMO, the carce people making dry plates don't usually blend much the emulsions for a greater sharpness, anyway mostly an straight emulsion is used because most of the joy comes from the involved adventure.
It's pretty clear that you have very little inkling about either dye ballasting & very monodisperse emulsions being needed to get variable contrast to work well or equilibration & why it affects emulsion blending. If you did, you would know that making a good variable contrast emulsion, or even a good, fast high contrast paper emulsion is very technologically challenging within the limits of single run emulsion making.
And because you can adjust latitude/ define your curve shape in many ways at the making stage in polydisperse emulsions, you should only even contemplate blending once you have totally exhausted all other possibilities of adjustment (change your addition rates & iodide % for a start - it's all documented on here - you have either done almost nil research, or actively dismissed the writings of actual experts as knowing less than you think your random googling tells you). Manufacturing only went over to blended emulsions once monodispersity became prevalent. For example, while the old Efke/ ADOX CHS films were polydisperse single emulsion materials, the current CHS-II is a blended emulsion (likely because it uses much more monodisperse emulsions) coated in a single layer.
Here we were speaking agout the well known multi-layer effect in the latitude boosting. The 1 layer kodachrome was a pitfall, still slides have a way narrower latitude requiring less the latitude boost, while print film (color/bw) has evolved to deliver insane highlights latitude, provided by the multi layer: 9 layers, 3 per color in good color print film !! Why they take that effort ? Are you aware of the latiude boost it provides ?
A small amount of searching on here will tell you accurately about the benefits and shortcomings of polydisperse emulsions (and yes, Kodachrome was polydisperse historically - one emulsion per colour - what you are trying to claim about latitude is inherent to transparency film design). Latitude via multi-emulsion blends is a matter for worrying about only once you have a properly monodisperse emulsion - polydispersity by its nature gives an inherent wider latitude. Multi-layer is for when you run into problems with emulsion being so dissimilar in iodide content that you get equilibration problems, or that the internal layer turbidity is worse than interlayer reflectivity when you have attempted to control either through the use of absorber dyes.
Let me repeat it a final time: The core technology of the TMax films (TMX, TMY, TMY-II, TMZ) is laying extraordinarily well aligned ultra flat crystals over cubic crystals, all TMax films sport this core concept to provide insane latitude, insane linearity and fine grain.
With TMX you easily get 14 stops, or 18 with a careful processing, For that you require multi layer. If you blend the cubic in the T you destroy the alignment provided by the SHEAR THINNING (https://en.wikipedia.org/wiki/Shear_thinning) in the coating cascade, but you need the cubic emulsion for the linear extreme highlight latitude, so you won't find a way to avoid multi-layer for the TMX if wanting those 14 to 18 stops.
It is totally ridiculous your theory of TMX being a totally different concept than TMY, beyond speed, they are different flavors of the same, sharing linearity and insane latitude. You won't find a serious evidence stating that TMX is single layer, this is a urban legend with no base.
Your deduction that TMX is single layer because of glass plates is simply ridiculous, this is not being aware of the core technology that shapes the TMax product range.
I won't say more about this off-topic.
Basic methods of how to adjust the curves of a blended multi-emulsion T-grain (or any other monodisperse grain character film) have actually been disclosed/ strongly hinted at on this site (silver and iodide adjustments between the emulsions - finer grain emulsions gain contrast faster than coarser grained ones). But you either don't know what you are looking for or refuse to learn. You are attempting to blather your way out of another mess of your own making by throwing around randomly googled rheological terminology without considering that you are making fundamentally self-contradictory statements: if your claims are correct, how can 5 separate colour emulsions (let's say green sensitive) be blended into three layers for coating when they might all contain high aspect ratio/ t-grains? Because that is what is done in reality. Quite apart from the fact that the T-Max 400 electron microscope image clearly shows several quite different T-grain sizes within what you have spent a lot of words claiming to be one discreet layer...
And if you had done your primary source research properly, you'd have found that when T-Max films were first introduced, it was T-Max 400 that was regarded as the most challenging of the three in its highlight behaviour. That has changed, following multiple revisions. Consequently, applying blanket statements to all three T-max films as they currently exist is inaccurate. Absent further information to the contrary, the most likely constructions are: T-Max 100, single layer, multiple T-grain emulsions; T-Max 400, multilayer, one using high aspect ratio T-grain emulsion(s), the other more 3D emulsion(s); T-Max 3200, multilayer, multiple t-grain emulsions. This would be in line with industry norms for these speeds of film (which essentially means 'we copy what Kodak does - with good reason').
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