So, what companies actually coat film?

Photo Engineer · Dec 7, 2006

timeUnit said:
PE?

Care to elaborate?

On what?

PE

Photo Engineer · Dec 7, 2006

A single layer of the Kodacolor Gold 400 films that I worked on contained about 1900 - 3000 mg/square meter depending on type. This one layer also contained about 1700 - 2000 mg/meter square of gelatin.

There are up to 14 layers in a modern color film, with sometimes over 9 emulsions.

Slow emulsions are about 0.2 microns in size and large ones range up as high as 3 - 4 microns. Iodide can vary from zero to 10% and can be distributed in a variety of methods in the grain.

Emulsion size, amount of silver coated and iodide level all contribute to the final speed, sharpness and grain of the resulting product.

In paper products, the laydown can run as low as about 200 mg/square meter to over 10x that value and usually uses emulsions in the 0.1 micron to 0.3 micron size. The exception is the blue sensitive layer of color paper which uses an emulsion of about 2.0 microns and high silver levels to get speed and development rate to match the other layers.

It is normal for a paper to have a dmax of about 1.8 - 2.2, as this is the physical limitation imposed by multiple internal reflections and surface characteristics. As a general rule lower dmax is seen with matte papers and higher dmax is seen with glossy papers.

PE

Roger Hicks · Dec 7, 2006

uraniumnitrate said:
I can’t give you a Bsc in photographic science thought the internet!
[/B]

Nor can Grant Haist, Pierre Glafkides, Ron Mowrey and others whose papers and books I have read over the last 40 years, and with whom I have corresponded and on occasion spoken. Or the emulsion designers at Ilford and Kentmere whom I count among my acquaintances and sometimes (gratefully) friends.

I may be less ignorant on this subject than you think, and you may be more knowledgeable than I think; we are clearly failing to communicate. I am far from an expert, but nor am I a complete ignoramus.

Yes, a contact paper is different from an enlarging paper. It is also slower. Does this bring to mind anything I said earlier?

One further tip: to reduce the incidence of exclamation marks, simply stop hitting the ! key. This has always worked for me.

Cheers,

R.

uraniumnitrate · Dec 7, 2006

Photo Engineer said:
A single layer of the Kodacolor Gold 400 films that I worked on contained about 1900 - 3000 mg/square meter depending on type. This one layer also contained about 1700 - 2000 mg/meter square of gelatin.

There are up to 14 layers in a modern color film, with sometimes over 9 emulsions.

Slow emulsions are about 0.2 microns in size and large ones range up as high as 3 - 4 microns. Iodide can vary from zero to 10% and can be distributed in a variety of methods in the grain.

Emulsion size, amount of silver coated and iodide level all contribute to the final speed, sharpness and grain of the resulting product.

In paper products, the laydown can run as low as about 200 mg/square meter to over 10x that value and usually uses emulsions in the 0.1 micron to 0.3 micron size. The exception is the blue sensitive layer of color paper which uses an emulsion of about 2.0 microns and high silver levels to get speed and development rate to match the other layers.

It is normal for a paper to have a dmax of about 1.8 - 2.2, as this is the physical limitation imposed by multiple internal reflections and surface characteristics. As a general rule lower dmax is seen with matte papers and higher dmax is seen with glossy papers.

PE

Okay that means the 1900mg is the total amount for one layer and that contains 1700mg gelatin which giving us what 200 mg silver if….!
Than the 14 layer would be 14x 200mg which is 2800 mg silver which is 2.8 g clean silver. That is even less silver I thougt it has.

Now that 9 emulsion could be misleading as the color films so called emulsion are, to begin with an a anti halo layer than the polyester base of the film and den again a new anti halo with that layer which hold the whole emulsion layer then the closest is the AgHal with the cyan than a diffuse filter so next would be the AgHal with the magnenta and a new layer on yhis is the yellow filter! The last one is the AgHal with the yellow and the top of that the safety layer.
Is that something more here that I didn’t know about?

And of course you are totally right about the papers but I would mention that to achieve the highest density you must also have a negative which have a blackness curve very close to the ideal 45 degree!

Ole · Dec 7, 2006

uraniumnitrate said:
... to achieve the highest density you must also have a negative which have a blackness curve very close to the ideal 45 degree!

No, to get maximum density you just need enough exposure. You don't even need a negative at all.

Photo Engineer · Dec 7, 2006

uraniumnitrate said:
Okay that means the 1900mg is the total amount for one layer and that contains 1700mg gelatin which giving us what 200 mg silver if.!
Than the 14 layer would be 14x 200mg which is 2800 mg silver which is 2.8 g clean silver. That is even less silver I thougt it has.

Now that 9 emulsion could be misleading as the color films so called emulsion are, to begin with an a anti halo layer than the polyester base of the film and den again a new anti halo with that layer which hold the whole emulsion layer then the closest is the AgHal with the cyan than a diffuse filter so next would be the AgHal with the magnenta and a new layer on yhis is the yellow filter! The last one is the AgHal with the yellow and the top of that the safety layer.
Is that something more here that I didnt know about?

And of course you are totally right about the papers but I would mention that to achieve the highest density you must also have a negative which have a blackness curve very close to the ideal 45 degree!

For a negative B&W or color film, the design aim is a curve with a slope of abaout 0.6 and a latitude of as many stops as possible. To do this you need to blend 3 emulsions (on average) for a B&W film, and 9 emulsions (3 per region of the spectrum C/M/Y). These emulsions can be coated in individual layers such as in color film or in 1 layer (some B&W films). Some films have specially sensitized layers such as those 'adjusted' for fluorescent light.

Each layer has a different amount of silver.

Now, taking 0.6 as a mean for the film contrast, a 'normal' mid range grade 2 paper would have a contrast of 2.5 in the middle of the curve where it is straight. This gives a final print contrast of 0.6 x 2.5 or 1.5 for the mid tones of the print. Each grade of paper is about one unit higher or lower, so a grade 1 paper would be a paper with a mid tone contrast of about 1.5 and etc.

In no case can you get much above a 2.2 in density in either color or B&W paper prints due to the laws of physics. Addition of some special materials to the overcoat of a paper can increase dmax up to a maximum of 3.0, but this is rare and does not add much to the image. Special tools are needed to even detect this type of image. You need a goniophotometer.

In actual practice, prints are measured 2 ways. Density is measured by using a reflection densitometer and then the density of a step scale in a print along with a real scene is measured at viewing distance with a spot photometer. These two curves do not match and the difference is a real value used in measuring the entire 'system' quality of reproduction.

Go ahead and make pictures. But, remember that there are thousands of man hours of engineering behind them to make them possible and good. At the big three you don't dump and stir and coat!

PE

Roger Hicks · Dec 7, 2006

George Papantoniou said:
Hi Roger !!!!!!!

Do they (!!!!!) make you nervous, too ?????????:rolleyes:

WHAT!?! makes you think THAT!!?

Cheers,

R.

uraniumnitrate · Dec 7, 2006

Ole said:
No, to get maximum density you just need enough exposure. You don't even need a negative at all.

Yeah sure! If you only have black and white than you have the lowest and the highest thats for sure!

I meant whole density range throught out the entire image! Not only D=0 and D=2.2 there is something else between in black and white photography.
Thans to remind me!

Ole, I took away all the smiles because some people didn't like that you make me happy and laugh. Sorry, I really liked you comment!

Roger Hicks · Dec 7, 2006

uraniumnitrate said:
Yeah sure! If you only have black and white than you have the lowes and the highest thats for sure!

I meant whole density range throught out the entire image! Not only D=0 and D=2.2 there is something else between in black and white photography.
Thans to remind me!

Yes, and it's sort of hard to get both 0.0 and 2.2 without something in between.

Tonality, or at least 'sparkle' (according to Ilford and Zeiss), is a question of high MTF values at low frequencies. This is not the same as density or silver content.

And PLEASE lay off the exclamation marks.

Cheers,

R.

jim appleyard · Dec 7, 2006

[QUOTE
And PLEASE lay off the exclamation marks.QUOTE]

And the smiles while you're at it.

uraniumnitrate · Dec 7, 2006

Photo Engineer said:
Go ahead and make pictures. But, remember that there are thousands of man hours of engineering behind them to make them possible and good. At the big three you don't dump and stir and coat!

PE

Okay PE now I got you! And thanks!

"Go ahead and make pictures. But, remember that there are thousands of man hours of engineering behind them to make them possible and good."

Don’t you think for a minute that I don’t know!

"At the big three you don't dump and stir and coat!"

Well maybe just a little bit!

Paul Sorensen · Dec 7, 2006

Roger Hicks said:
And PLEASE lay off the exclamation marks.

Maybe he has a defective keyboard, did you consider that?

Alex Bishop-Thorpe · Dec 7, 2006

This whole topic sort of lost me in a sea of educated banter, but I've been interested to hear exactly what companies coat what for a while. I knew Ilford used to do it, and I didn't think Maco coated their own stuff. The list provided earlier was pretty useful and new to me, and worth wading through the exclemation marks for.

uraniumnitrate · Dec 7, 2006

jim appleyard said:
[QUOTE
And PLEASE lay off the exclamation marks.QUOTE]

And the smiles while you're at it.

Some people do make happy and make me laugh and Ole did just that! I wanted express myself and show it!
Do you have a problem with that?

Ray Heath · Dec 7, 2006

pardon my ignorance as i've never bought "rebranded" film, what does all this matter?

if you buy a "cheap" brand that may or may not be a high quality brand/type don't you just get what you paid for?

in this country our supermarkets are full of "generic" (cheap) brands that are made by high quality manufacturers but are relabelled/rebranded to sell as a cheaper alternative, they may be the exact same product as a known brand, you just never know, you have to decide if the cheapness outways any possible, and often undiscernible, quality issue

if you want high quality, always buy a high quality product

Dave Parker · Dec 7, 2006

Ray Heath said:
pardon my ignorance as i've never bought "rebranded" film, what does all this matter?

Ray,

You said the magic words...

You want a guarantee of high quality, then .....

Dave

PHOTOTONE · Dec 7, 2006

Ray Heath said:
pardon my ignorance as i've never bought "rebranded" film, what does all this matter?
if you want high quality, always buy a high quality product

ABSOLUTELY, however the SAME film can be found under several different names, distributed by several different companies, with many different prices asked. The prudent, cost-sensitive photographer can save 1/2 to 3/4 the cost of each roll by purchasing "off brand" film by "knowing" the source of what he is getting.

For instance, Agfa APX-100, while discontinued (due to shut-down of factory) is still widely available in 35mm, and also private label. Sometimes the private label is cheaper. same film. Why not save?

If you could save over $4.00 a roll for Fuji Slide film, by purchasing it rebranded by a distributor, wouldn't you? Same film, different name on
package.

In both examples we are talking about major top line product, just labeled differently. Now, in addition to the above examples, there are many situations where inferior product is purchased in bulk, spooled, packaged and sold as some "esoteric" emulsion. The knowledge of origin can be helpful in this case also, don't you think? Types of film that come to mind are various microfilm stocks, traffic & survellience film stocks, Cine film stocks, etc. Films that originally were quite low in price when purchased in bulk. Knowing the "source" for a particular film stock can help in finding the lowest price.

Ray Heath · Dec 7, 2006

PHOTOTONE said:
ABSOLUTELY, however the SAME film can be found under several different names, distributed by several different companies, with many different prices asked.....

sure, but we're not supposed to know that x is actually y

seems to me that all these posts are nothing more than wink, wink i know what's going on

if these products are the same, why would the manufacturer bother?

maybe it's so the manufacturer can release an inferior product without damaging their reputation

i can't get past the idea that if you want high quality, buy high quality

PHOTOTONE · Dec 7, 2006

Ray Heath said:
sure, but we're not supposed to know that x is actually y

seems to me that all these posts are nothing more than wink, wink i know what's going on

if these products are the same, why would the manufacturer bother?

maybe it's so the manufacturer can release an inferior product without damaging their reputation

i can't get past the idea that if you want high quality, buy high quality

Absolutely, but there are many of us on tight budgets for our personal photographic projects that wish to be able to shoot the maximum number of rolls for the minimum price, yet still use top quality film. For my professional work, I always purchase name brand, fresh stock.

A manufacturer can sell "custom labeled and packaged" film to a vendor in large quantity much cheaper, because there are no marketing or warranty costs involved. Same film. Not inferior. It is very cost effective to sell and ship 1 million rolls to one address on one invoice, than it is to ship to thousands of distributors worldwide, thousands of invoices, tracking, damaged in transit, etc. You understand economics, surely. This is why one can get identical quality from "rebranded" film, if only we knew what we were getting. I am sure the annual order from Walgreens private label film to Fuji is quite large, even now with digital in predominance.

Dave Parker · Dec 7, 2006

Myself personally, really don't even look at price when I am buying film, the price factor is such a small part of the reward factor.......especially when I am shooting for a client...

Dave

PHOTOTONE · Dec 7, 2006

We have two different markets here, on the one hand we have professionals who shoot for clients. I am one of those. I order fresh refrigerated pro film stocks for that. The client is charged for the film used, and processing, and scanning, and at a profit. It behooves me to use the best, and I do.

On the other hand, we have photographers who make art, for arts sake, with no client footing the bills. I am also one of these. For these applications, it is all money out of my meager pocket, and I prefer to economize where I can as long as my "art" doesn't suffer, therefore I look to find the lowest cost versions of the high quality films I prefer to use. Sometimes this is as simple as just purchasing "short dated" film, other times it is a detective novel to decipher what is what in the "rebranded" film genre.

PHOTOTONE · Dec 7, 2006

I should say that The client is charged for the film used, and processing, and scanning at a profit, in addition to my shooting fees.

Dave Parker · Dec 7, 2006

You are indeed correct, I have been shooting for a client in one for or another since I was 13 years old, so I guess, I don't have the perspective that you do, but I do know that shooting and getting the image, the price of the film is the least important thing in my mind...when I shoot for pleasure, I have never once worried about the cost of the film..

Dave

Photo Engineer · Dec 7, 2006

When I did professional or military work at Cape Canaveral or in South East Asia, the cost was in lost lives or lost information if the film was bad. We didn't worry about the monetary cost.

When I take a casual picture today, I don't want it lost to film defects, paper defects or processing defects. Recently, I lost part of the pictures on a roll of pix and am arguing it was a processing defect, while the processing lab says it was a film defect.

Whichever way, I don't want a defect and I want good curve shape too.

PE

Dave Parker · Dec 7, 2006

Even with th current state of things with film manufactures, I pay the price, I take the shot, I don't scrimp on my film that is the most important part of the equation, I don't buy off brands except when in a pinch, and I don't scrimp very often, even in a remote area, I will pay what ever ridiculous price the local shops are charging, I shoot either kodak or fuji, and illford when I am doing B&W, that way I know that I can trust the film in my camera, I don't have to speculate, I don't have to worry...

Dave

So, what companies actually coat film?

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