For me it has nothing to do with numbers.
Originally Posted by Ray Rogers
C-41 and RA-4 are in practice for me; more forgiving & flexible in the camera, less expensive in general, and easier to work in the darkroom.
I also find the quality of the output is more consistent.
It is really tough for me to see a downside to the neg-pos system because it works so well.
Mark Barendt, Ignacio, CO
"We do not see things the way they are. We see things the way we are." Anaïs Nin
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.
Forgiving, & inexpensive certainly.
Big downside for me was greater cost to get to first enjoyable image...
the greater need for contact sheets
more finicky filtration behaviour when printing
and less archival print materials...
Don't know what the experts round here think, but according to Wiki,
Michael Langford claims "Reversal films are the preferred film choice of professional photographers for images intended for reproduction in print media. This is because of the films' high contrast and high image resolution compared to negative (print) films."
Of course, that comment is now out-digitally-dated.
I mostly enjoyed the immediacy and simplicity of an E6/Ilfochrome match.
Last edited by Ray Rogers; 02-15-2011 at 09:13 AM. Click to view previous post history.
Even if you can get "quite good" imaging without masking, why not to implement masking in negative films because it is possible, and probably quite easy to do so? I think this is all about development. Many inventions are not groundbreaking, but fine-tune the results. Nothing is a "must", but today we take the extraordinarily high quality for granted, while it's mostly thanks to dozens of small inventions during decades.
With slides, if you added a mask, you would need a compensating blue filter in the projector so that orange mask + dye impurities + blue filter together equal to neutral density, but you would have huge light losses and it wouldn't be practical.
But orange mask in negative material, which is not to be viewed directly anyway, is very practical and is very easy to compensate for in all workflows. For example, RA-4 papers have different sensitivities for R/G/B emulsions so that orange light will work directly. (In fact it's made even more red-orange with the filtration, so the "mask" helps with this. This is because of color separation without the need of yellow filter layer in paper.)
However, orange mask has started causing some (usually minor) problems in the 2000's because of some scanners that are built by idiots, and software written by idiots. Luckily, we don't need to discuss this at APUG in detail which is why I love this place.
PE and Ray, please try to keep calm... I don't know what's going on with you two or why, but I know it doesn't make anyone feel good.
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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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)?
Originally Posted by Photo Engineer
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.
Originally Posted by Moopheus
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.
Last edited by hrst; 02-15-2011 at 10:02 AM. Click to view previous post history.
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.
Originally Posted by Photo Engineer
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:
Originally Posted by Ray Rogers
$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.