layers and operation in colour films

pellicle · Apr 15, 2008

Hi

I understand that colour films (negative and reversal) have a number of layers for both filtration of frequencies and recording the various frequency bands. I'm looking for a good reference on this (web or book) if anyone can point me in this direction I'd be very interested

thanks

Mike Wilde · Apr 16, 2008

Haist perhaps?

I do not have a copy, but I understand that later editions of Grant Haist's 'Modern Photographic Processing'.

A quick Google suggestes that Volume II might have more colur information, but if I could lay my hands on a set, I would want all volumes.

I suggest a search though a uni research library.

Michel Hardy-Vallée · Apr 16, 2008

Yep, Haist is a pretty solid reference if you know some chemistery. I borrowed the two volumes from a local library, and read them as bedside stories while I was working on my MA. It must have taken me a few months to read the two volumes, but boy do you feel clear-headed afterwards!

But if you're just looking to understand how the different layers of colour film work, I suggest you pick up a general purpose photo manual. Hedgecoe's, or the Uptons are excellent and have detailed illustrations. The Life library of photography is good, and so is the Kodak Encyclopedia of Practical Photography. You might find some stuff on Kodak's website as well.

A bit of Googling "how colour film works" can yield useful basic info like this:
http://science.howstuffworks.com/film8.htm

AgX · Apr 16, 2008

I have got quite an extensive library but I can't advise on any book if it should reveal much more than the basic 3-layer principle. All the information seems to be spread amongst side-notes, historic references, lectures by the industry...

The best comprehensive text so far I found in Dutch book, so it won't be useful to you. And even that speaks only of two halide layers per colour, whereas meanwhile three is common.

AgX · Apr 16, 2008

Pellicle,

the principle is as follows:

-) the basic layers are typically placed in the sequence (surface to base)

bluesensitive-
yellow filter-
greensensitive-
redsensitive-

in addition of course
surface-
subbing-
antihalo-
(antistatic-)
(anticurl-)

to make it more complicated
many films of today have the colours layers seperated in two or three sublayers with a different scope of crystal sizes, which makes 1x2plus2x3 or 3x3. Behind this are similar thoughts as in BW multilayering: control of gamma, latitude, grainularity. The sequence is high-, medium-, low-sensitive.

sometimes
UV filter-
red (or magenenta) filter-layer
seperation-layers between the colour groups

for the yellow filter-layer Carey Lee silver (collodial silver) is the classical approach, however a more modern concept employs a dye as its absorbtion charecteristics are more profound.

The thickness of most layers will be less than 2μm.

Photo Engineer · Apr 16, 2008

There are a few more than AgX lists above but he is correct in the essentials. See the cross section I posted here on color film. It shows and identifies each layer. It is in the emulsion making and coating forum.

Basically it is /overcoat/fast blue/slow blue/CLS/fast red/IL/fast green/slow green/IL/slow red/AH/subbing/support/AC/. Sometimes the fast red is under the greens and sometimes not depending on film. On the back are antistats, anticurl and other things. Subbing is present sometimes for example, but in some films it is not present due to the method of manufacture.

See the excellent article by Chuck Woodworth from Kodak on (I believe) howthingswork.com .

PE

AgX · Apr 16, 2008

Photo Engineer said:
There are a few more than AgX lists above but he is correct in the essentials.

PE,
Which ones did I leave out?

Photo Engineer · Apr 16, 2008

You left out some interlayers and the division into fast and slow components.

Awww heck, here it is again. Note that the labels don't distinguish fast and slow layers, but they can be seen in the light and dark colors in the example. This also shows the UV overcoat and does not show component inversion.

It varys with each film.

PE

Photo Engineer · Apr 16, 2008

AgX;

My apologies, I missed part of your post. You have everything there needed. Sorry.

PE

Mr Bill · Apr 16, 2008

I seldom see Hunt's book," The Reproduction of Colour" recommended, but this would be high on my list. I seldom see it recommended, but if your goal is to obtain a fundamental understanding, I think it's hard to beat. http://www.amazon.com/Reproduction-Colour-Imaging-Science-Technology/dp/0470024259

The section on colour neg films (Chapt 12, Subtractive Methods in Colour Photography; see the section on Integral Tripacks, I believe) is short, but fairly comprehensive, discussing reasons for the order of layers, etc. As I recall, it has several cross section photos of color negative film, etc.

If you are after PRACTICAL information, this is probably not a good book. But if you want to understand WHY things are done, you ought to have a look.

AgX · Apr 16, 2008

I did not obtain this book yet (due to costs), but reading other books by Hunt had made me place this one on my wish list.

It would be great if it revealed more than what presented here so far.

Photo Engineer · Apr 16, 2008

I've posted this before, but perhaps it was overlooked.

The entire composition of a color negative film is disclosed in USP 5,302,499.

It includes structures of couplers, amounts, the works!

PE

AgX · Apr 16, 2008

I tried in vain to read the full text at google, did not show up...

Will it reveal why each layer is placed where it is, and its function?

For learning purposes it will be far more informative to get to know what intention is behind any structure rather than just getting to know how something is structured.

Photo Engineer · Apr 16, 2008

This patent gives no tutorial. It assumes you 'know' things and are 'skilled in the art'. Sorry.

Try www.freepatentsonline.com.

That is where I got my copy.

PE

pellicle · Apr 17, 2008

Folks

thankyou so much for the summaries and book references!

I've got a basic description in a book at home (Australia) but I'm sort of just pondering a few things and thought I'd like to munch on a discussion of the details.

Such things as (if I recall right) the arrangement of layers not being optimal for the spectral spread and how each layer interferes with the next.

Certainly this stuff is the result of extraordinary thinking and research.

sadly I do 90% of my own work in black and white so I miss out on the advantages ;-)

layers and operation in colour films

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