Consistency question: Kodak vs. Fuji color neg film

Moopheus said:

Then why do slides look normal when projected or viewed on a light table? Wouldn't the color deficiencies be obvious (even to someone with vision issues like me)?

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Because they are "good enough". Please note that RA-4 paper, as all viewing material, is unmasked anyway, so we can never see perfectly "pure" dyes anyway. Even when the images are offset printed, the inks have impurities in their absorption. Or when we look at them on CRT monitor, the primary RGB wavelengths are not optimal. Or if we look at them on LCD monitor, there's again a purity problem in RGB dyes in the monitor.

So when you print C-41 neg to RA-4 paper, you have one unmasked stage, just when viewing E6 slide directly, so there is same amount of color "impurity".

If you print E6 slide to Ilfochrome or reversal chromogenic, you have two unmasked stages. So, masking is done in C-41 films at the "first stage" because it's possible. I think this is more important in motion picture films because there are more stages, typically camera neg, interpos, interneg and final print. Three masked and one unmasked stage. Four unmasked stages could probably accumulate visible amount of color impurity.

Ray, I would guess that they are doing all they can to find as good dyes as possible. I also guess that the dyes are quite good even without masking. This can be seen in E6, RA-4 and motion picture print materials.

Photo Engineer said:

I think that you will find that for color accuracy and excellent tone scale reproduction, the color neg-pos system excels. The pos-pos system can produce beautiful prints, but if unmasked, the process is less faithful and introduces many faults in the reproduction. A masked pos-pos system is creatable, but the transparencies are not viewable due to the orange mask.

Masking in the pos-pos systems, as is used for example by National Geographic, will produce stunning reproductions. However, one does see a loss of detail in reds in most reversal systems due to the efforts to correct color.

Cross processed C41 films in E6 may give a weaker mask due to the fog formed during the process. IDK for sure, but the samples I have seen look normal. Green color negatives indicate fog during processing or before processing.

PE

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Green always occured for me when using rehal processing, a b&w first developer though instead, such as Rodinal, then using E-6 colour developer at the colour developer step to produce a neg.

Ray Rogers said:

I am not against masking, I just think we should strive to find better dyes,
or systems where the need for masks would be superflous, because less is simpler & cleaner.

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Dye chemistry has been a huge area of research for over a hundred years. There are billions of $ involved. The chemistry is extremely complex, and synthesis is very tricky:
$thousands per gram, and those items are not even close to being "ideal". It is no simple matter to 'find better dyes'.

The E6 color developer is a fogging color developer. This may contribute to the green. IDK.

Now, on with the masking..... You see, all dyes fade with time and all dyes have impurities. This is the nature of all things in the real world. We live with imperfections. Masks are an effort to remove dye hue imperfections and antioxidants are used to improve dye stability. The list of efforts at improvement are lengthy.

Negative films are used in motion pictures due to their high fidelity and good sharpness and grain. It was possible to produce motion pictures on pos-pos film systems, but the generational deterioration even with masking led to bad prints. But, more to the point is the pos-pos print system tone scale. Here you are printing toe to toe and shoulder to shoulder thereby compressing the scale visible in the final print. In neg-pos systems you print straight line to toe and shoulder therefore eliminating scale compression. And, internegative films have an upswept shoulder that corrects for the toe of the original positive image.

On the whole, you might say that the professional Hollywood photographers have chosen neg-pos for the overall quality it represents. Still slides were chosen simply because the original could be viewed on a light table quickly, for final selection by an editor. It took one less step in the procedures before final selection.

Also, the their zeal to make high quality slides, the R&D people often made materials that exaggerated colors and contrast which did not look at all bad in magazines.

And, when I worked in motion picture part time at the Cape, and also while doing some side-by-side R&D at EK, I saw the MP industry reject pos-pos systems even with special masked positive films. I've included some of that reasoning above.

PE

I think that Ray still has one very strong point; "less is simpler". This is also the reason for neg-pos system in most cases, and for reversal film in one case:

If the final image is a positive to be projected, and one is enough (no need to copy), then a reversal film indeed is simplest and easiest. It also provides great quality because there are no losses in copying. There is one toe and one shoulder which is unavoidable, and one generation of non-masked dyes which is also unavoidable. You just need to select the right film with the properties you want and nail the exposure down. In this case, it is simpler and more quick to use reversal film because with color negative film, you HAVE to make a copy even if you didn't want to do it.

However, when we need to have copies, it turns out different way. If we have a positive image, we have to run the more complex process twice, and we have the drawbacks mentioned (overlapping toes & shoulders and two unmasked stages). The negative system is of course much more simple as we all know - we have to make a copy in this case, too, but the chemical process is easier for both original and copy film, toe and shoulder can be eliminated from source material remaining only in copy material, and there is only one unmasked stage.

It's the "natural" system where light causes the film to get darker.

Of course they could make reversal materials that work like negs; they would be masked and they would have longer exposure range (lower contrast index), and the toe and shoulder would be discarded in copying just like with negatives. But would there be any benefits? They would be more difficult to design and the reversal processing at every step would be an extra nuisance.

The more we need copying stages, the more the easiness of the negative process becomes crucial.

Ilfochrome printing is a special case and it has its price (and yes I'm talking about money). As most professional Ilfochrome printers know, it's not an all-around technique, and for portraits, color neg is ofter preferred for its more subtle and less contrasty look. These are all different artistic tools with different look and feel and purposes.


BUT, there is still something missing from this whole picture. It's the results DR5 claims. It seems that doing a reversal processing to the very same films yields a better grain and sharpness AND still very good tonal range than negative images. They are for BW but I'd like to hear the technical explanation why. http://www.dr5.com/blackandwhiteslide/filmtests.html

Less IS simple, until you have to drag out the projector, the screen and move furniture! BTDT. Home slide shows are a pain. Laying them out on a fixed light table is not.

As for demos, take a look at your reference again. It is very often easy to confuse contrast with sharpness or to lose grain in density. I would not judge these until I saw the actual curves and saw the images adjusted to give the same blacks (and whites). You note that the blacks differ quite a bit there as do some of the whites. So, I cannot be certain. I would place them as being more equal than different just OTOMH. You cannot get something for nothing.

I would also add that the process may be adjusted for the ones on the left, but not for the ones on the right. There are optimum development times for every negative film in every negative developer.

PE

it's not so bad when your enlarger can swing up to project on a wall though but changing film is annoying.

hrst said:

So when you print C-41 neg to RA-4 paper, you have one unmasked stage, just when viewing E6 slide directly, so there is same amount of color "impurity".

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Okay, thanks, I gets it now.

One more thing missed in this that should be added.

Color papers are limited to about a Dmax of 2.2, while E6 films go to about 3.0. OTOH, ECP used in motion picture goes up as high as 5.0! http://motion.kodak.com/motion/uplo...crobat_en_motion_products_curves_2393Char.pdf

PE

Ray Rogers said:

Can you not understand me when I say to you that in the pos-pos system very beautiful images are produced without the use of masks, and that makes me wonder if masking really is a must in the neg-positive system or if it is just something we have come to accept, without question?

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There's a difference between something that looks good, and something that's accurate. The two can overlap, as they do in modern negative films.

Many people like Velvia. They think it looks fine. They actually prefer Velvia compared to more accurate, less saturated films. That's a choice they get to make.

Is one better than the other? Depends on what you want.

Photo Engineer said:

One more thing missed in this that should be added.

Color papers are limited to about a Dmax of 2.2, while E6 films go to about 3.0. OTOH, ECP used in motion picture goes up as high as 5.0! http://motion.kodak.com/motion/uplo...crobat_en_motion_products_curves_2393Char.pdf

PE

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This is one of the reasons I wish it was possible to re-visit the potential of a colour material that is easily available, combined with processing that yields a negative that prints well on both paper and easily available transparency material.

Sort of like the old Seattle Film Works approach, but with updated R & D.

The old print film for amateur film, now long gone, had the same wonderful curve shape and the slides you could make from it were unmatched by anything due to the tone scale! When you shot a 4x5 negative, contacted it to the print film and then looked at that with projection (yes it was possible) it was amazing.

PE

I got a 100ft roll of 35mm Vericolor Print Film from Ebay. Manufacturing ceased somewhere in the 2000's, I think mine has expiration date in 2004 but it still seems to produce usable results. The process is very conveniently C-41 even for this positive material. Of course contact copying in a small 35mm format loses resolution a little bit compared to the sharpest slide films such as Provia etc, but this is not so bad. MP film is copied too (with more stages) and has even smaller format. Slides made from Superia 1600 look gorgeous and you can adjust the color in copying if you had some special color temperatures there while shooting.

When you can do prints from slides, and slides from negs, you can shoot both neg and reversal film without getting stressed over the selection too much. Both have their own look. Still I tend to like taking two cameras and shoot both neg and slide simultaneously because I can't decide...

I think it's a bit harsh what you said about home slide shows . I think it's totally worth the hassle. If you want to see a projected image and how cool it looks, there's no other choice. For our hobbyists, setting up a bit more permanent projection place is also possible. It's easy to integrate with "home theater" .

Sorry, but my family enjoyed prints. They used to take many photos and carried the prints around with them everywhere. Much more portable and storable as prints than as slides. More room to write on the back. We all had disc cameras and Pocket Instamatics (110) and Instamatics (126) always filled with negative film.

If the print film you have is 4111 (I think that is right) then the raw stock keeping at room temp is not the best once the package is opened. Also, there are little "duplicators" that fit on the front of any 35mm camera and allow you to "photograph" your negatives or slides. This method gives a good sharp image. I have made many negatives from slides this way.

PE