Is color process could be made successful like a bw

Discussion in 'Color: Film, Paper, and Chemistry' started by Mustafa Umut Sarac, Apr 11, 2011.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I really could not use this Rollei 35 S camera. And I have no lightmeter and it makes everything more complicated. I am generally use cheap kodak and fuji film and I select sun casted areas for their saturated colors. But at every occasion , when the sun little bit loose its energy , photographs tend to loose their colors faraway faster , they look like bw color scans. Yes , I can put the lost colors with photoshop saturation but this was not I expect from a Rollei.

    I thought BW pictures of gallery and my gallery are faraway technically better than most color scans.

    Now the big question , Can I shoot for shadow and develop for highlight at color photography like zone system ? What is the way to get same colors at lower illuminated places as eye sees ?

    Umut
     
  2. holmburgers

    holmburgers Member

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    Generally with color-negative film, you can get more saturated colors by overexposing 1 stop or more. If your pictures in shadow areas are very low-saturation, they might be underexposed.

    Since there is less flexibility in color processing, the old zone system adage might not work, but exposing for the shadows is still a good idea, depending on the scene of course.
     
  3. Athiril

    Athiril Subscriber

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    With colour negative overexposing will decrease your saturation. The amount of opposing colour will increase more than subject colour density, thus less separation and also less contrast.

    Spot meter whatever you want to have maximum saturation. For sunset/sunrise, this means severely underexposed foregrounds, just like slide film or digital, so you'd use a gradual ND or gradual reverse ND anyway, which you should be doing anyway to get the high pictorial contrast unless you want flat pictorial contrast.

    Some films like 160S don't respond well to sunset colours, low saturation/low contrast doesn't explain failure to reproduce colour, it still should reproduce the colour, avoid those.
     
  4. markbarendt

    markbarendt Subscriber

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    Well we need to remember that lightness and saturation are not the same. A thicker negative simply prints lighter at a given enlarger exposure than a thinner one.

    So, extra exposure of the film requires a corresponding eNlarger exposure change to place the main subject at the same brightness on the paper. As long as the print is coming from the straight line of the neg there will be little if any difference for the main subject on negs that are exposed several stops differently.

    What extra film exposure can do on C-41 film is give us better shadow color and tone separation by getting them up onto the straight line. Better shadow color can easily be viewed as providing a better/more saturated photo.

    Extra exposure reduces graininess too.

    Given the really long straight line available on C-41, some extra exposure has little if any downside.
     
  5. holmburgers

    holmburgers Member

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    I always heard that it was the opposite effect. Granted, I've never done rigorous tests, but the thinking is that overexposing puts down more dye in the film, and thus stronger colours. The opposite is true with slide film, where more exposure equals less dye.

    At any rate, mark is right about reducing graininess, and that's probably the biggest reason to do it.
     
  6. Athiril

    Athiril Subscriber

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    Internet myth. It doesn't tell you the whole story. More dye is the reason it's lower in saturation. As there is a smaller difference in max density minus min density of a particular colour. High density increases at a lower rate than lower densities with more exposure.

    Mid tones is where the maximum contrast and saturation is.


    Ever increasing exposure works only when your real life saturated objects are not in the highlights, and generally are below mid tones at a normal exposure at box speed. Try it sometime on a vivid sunset. You'd walk away with the conclusion that C-41 is rubbish for landscapes.
     
    Last edited by a moderator: Apr 12, 2011
  7. Athiril

    Athiril Subscriber

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    Extra exposure increases graininess, try it some time. You can end up with a thin image (read: thin image) where minimum image density is close to max.

    Better shadows does not equal more saturation. You are compromising saturation above mid tones, and the tones above mid tones get compressed.

    The colour separation gets smaller and smaller on the negative the more above mid tones you go.

    Try shooting a sunset some time, and expose the sunset colours as mid tones, then expose for the shadows on the foreground and see where you get.
     
  8. markbarendt

    markbarendt Subscriber

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    Not understanding what you are really saying here. Extra exposure increases image density. True of both paper and film.

    I do this regularly. Ilford agrees with me on the grain issue too. http://ilfordphoto.com/Webfiles/20061301945161573.pdf

    On the film, the tones only start getting compressed when they reach the shoulder. As long as we print from the straight line portion of the curve then separation of tones remains constant.

    On films like Portra there is room to place a normal scene easily 3-stops up from what an incident meter might suggest without losing color balance or detail. This does make for a thick neg and requires more enlarger exposure to place the subjects in the scene on the heavily exposed films at the same brightness on paper as those from a "standard" exposure, but the relationships remain.

    The problem your posing isn't really about "getting that huge range all on film", it's about "getting it all on paper."

    The problem you are posing here is a camera work problem where the photographer allows the subjects to get too far apart exposure wise.

    Shooting a trash shot doesn't help.
     
  9. Athiril

    Athiril Subscriber

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    No its not about getting it all on paper, you are making several assumptions, the colour separation decreases with exposure on the negative. Tones start to compress even at +1 stops, regardless of what you want to believe, you need to give it a go and analyse the actual negatives.


    Extra exposure increases density, hence you get a thinner image on a denser negative. Minimum density increases faster than maximum does with increased exposure. This also causes increased graininess.
     
  10. 2F/2F

    2F/2F Member

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    Why not?
     
  11. markbarendt

    markbarendt Subscriber

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    Your use of the word 'thinner' is making no sense in this context unless you are talking about the print getting thinner, less dense, because of the negative is more dense, thicker, and blocking more light in the enlarger.

    What am I missing in your point?
     
  12. mts

    mts Subscriber

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    HLS (hue, lightness, saturation) is one of several color measurement systems; RGB/CYM is another and all are valid representations. Consider HLS in which S (saturation) is the percentage of grey in the image with zero being pure color. It is evident that denser negatives, viz. ones that contain greater amounts of CYM dye components, have greater percentage of grey and therefore less color saturation. Sometimes thinking digitally is worthwhile even in the analog world.

    I too normally slightly overexpose color negative films, for example rating Portra 160NC or Fuji 160S at 125. I find highly saturated colors too garish and prefer less of them; in fact, black & white is often the most pleasing representation.
     
  13. Athiril

    Athiril Subscriber

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    mark:

    N exposure and N+x exposure for example;

    N+x: (dMax - dMin) < N: (dMax - dMin)

    N+x has a denser negative, but a thinner image (on the negative), the image density range is maximum minus minimum density, ie: black and white are closer together on the negative in terms of optical density.

    Less gradiations on the negative (though still plenty unless it becomes severe)

    Displaying min and max density at the same print reflectivity or RGB values requires the contrast to be stretched out, more than the N negative, grain is no longer noise once moving to a print or scan, as it is now part of the signal being used, and is treated the same - the grain contrast is increased too.
     
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  15. markbarendt

    markbarendt Subscriber

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    Athiril

    The thinner description still isn't making any sense. :confused:

    What it seems like you are trying to say is that each stop of extra exposure adds less density than the one prior, essentially the separation of tones gets smaller and smaller as exposure increases.

    If true, this would mean less detail is available in the highlight areas. If true it would also seem that Kodak's curves are wrong, i.e. The straight line should actually be curved.

    Across a single negative in a shot of say a wedding party the bride's dress could never show as much detail as the groom's tux. The bride's chocolate Lab would have better color separation than the Bridesmaid's light blue dresses.

    -------

    I did a test a while back. Several 5-shot/stop bracketed sets of 35mm 160nc film.

    Contact printed them.

    Across a single scanned contact print the color balance remained constant.

    I printed several versions varying only enlarger exposure to place one common neutral tone at the same point on paper and it was pretty darn easy to make the variously exposed frames match nicely.

    Admittedly this wasn't a rigorous lab study but I was carefull to do things carefully and used PS to measure the resulting print scans.

    I found no practical difference in detail or color at the main subject.
     
  16. markbarendt

    markbarendt Subscriber

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    Yes this can be done like the zone system or a push.
     
  17. holmburgers

    holmburgers Member

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    Interesting discussion indeed.

    Athiril, by saying exposure "thinner" in reference to overexposure, do you mean a thinner range?

    As for increasing graininess, I just don't know about that. Larger grains are inherently faster, thus with underexposure you are getting a high percentage of these large grains. It makes sense that overexposure would lead to more of the smaller grains being exposed. Not to mention, this is something you notice in low-light photos, the shadows are often very grainy/noisy. Granted, I've never printed these optically...
     
  18. hrst

    hrst Member

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    Athiril's math indeed is just a description of the characteristic curve (exposure vs. density).

    mts' HLS/CMY math is a mistake. This extra complication makes it difficult to see if it is in error or not. But in fact, the actual error in his deduction is that the printing stage, which is simply a subtraction operation from the CMY values, is ignored. When it is added, we end up with exactly the same CMY and HLS values given that the H-D curve is straight. In the end, it is just very simple; the curve shape tells us everything. If we have a linear system, the bias point does not matter; we can make additions and subtractions as long as we are on the linear region. Exactly the same works in analog electronics.

    If the curve bows or shoulders, the contrast indeed is lower. Today's films, however, have very long linear portion.

    The old wisdom says that increasing exposure reduces contrast and thus perceived saturation. This has been a well-known fact. Somehow it got swapped around and became an internet legend in a completely opposite form.

    However, with today's films, in most cases, there should be no difference in contrast and saturation with slight overexposures (+1 to +2 stops) due to shouldering.

    I think it depends on what you are shooting. Athiril's speaking about sunrise and sunset, where +15 stops is well possible when metered from the sun and nearby clouds compared to the landscape. This can really land on the shoulder of the film, unless metered like it was a chrome film - from the highlights, then adding a few stops. However, with neg film, you can of course place them higher than with chrome film (e.g. +5 instead of +2), but there still is a limit. If you measure a sunset scenery "from the shadows" as usually instructed for neg film, you go over this limit. "Expose for shadows" is just a rule of thumb for most subjects.

    OTOH, even if there is no shouldering, there still is the toe. With subjects with important shadows with colorful objects in the shadows, by overexposing a stop or two, you make sure that the shadows are not on the toe - and increase their saturation and contrast, without altering the saturation and contrast in midtones and highlights - given that the highlights are not difficultly high. This part is true in the internet legend, but the legend is wrong in making this a rule of thumb which it is not. You need an understanding of shadow contrast vs. midtone contrast vs. highlight contrast and understand how this relates to a particular subject.
     
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  19. Athiril

    Athiril Subscriber

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    markbarendt, you are looking at a print, not the negative, there isn't less detail, but less contrast. But on top of lower contrast, minimum opposing density rises, so the colour separation is also smaller.

    The best saturation/contrast is around mid tones. If it was such a straight line, you wouldn't need to raise exposure for things below mid tones. And I wouldnt see reduced contrast and saturation above mid tones. There is not much saturation in white to lose.

    With a thinner range, grain contrast increases if they are displayed at the same contrast as a broader range negative.


    Blue dresses are a more pure (saturated) colour than a chocolate Lab to begin with, and such light dresses would be around or just above mid tones, and a chocolate Lab below it by the sounds. There is no saturation in white to lose, contrast isn't detail, you can have more detail in low contrast object then you can in high contrast, and also vice versa.


    "Yes this can be done like the zone system or a push."
    You mean a pull.
     
  20. markbarendt

    markbarendt Subscriber

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    Exactly!

    This is a great point. I see saturation in two ways, one is technical, the other perceptual. Technical saturation is akin to color balance, i.e. A subject reaches proper or design saturation when that subject has enough exposure to be on the straight lines of all three curves. It is simply the design standard. Doesn't matter if we're talking about Velveeta 50 or 400 No Color. :wink: :laugh:

    Perceptual saturation is a different animal. Perceptual saturation is driven by composition, lighting, exposure placement of subjects, the development regime (N, N+, N-), paper choice......

    This is what I'm saying too.

    And this is my experience also. It is an artistic choice simply giving shadows more weight in the exposure decision with almost no downside for most subject matter.
     
  21. markbarendt

    markbarendt Subscriber

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    The reason I normally reference the print is because the negative is just an intermediate media. I don't hang my negs on the wall.

    I only care about what the negative produces.

    I am not saying there are no limits, but the toe is the close limit, a bit extra exposure to move subjects up off the toe can improve; our ability color balance a print, the separation of tones in the shadows as well as reduce grain and improve detail because we don't have to print from the toe.

    I think I see where we are not talking the same language.

    I don't see saturation as getting close to a pure primary mid-tone color like red, green, or blue.

    Chocolate lab brown and robins egg blue can both be fully saturated colors.

    Saturation for me is simply a measure of how close to "normal" or "expected" the color gets.

    Actually either.
     
  22. markbarendt

    markbarendt Subscriber

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    This is the idea I'm trying to get across. http://www.apug.org/forums/viewpost.php?p=1166813

    Yes I know it's specifically about B&W but the theory is sound. The significant differences between B&W and Color are simply 3 curves instead of 1 and dyes replacing the silver.

    The boxes in Ralph's diagrams define the portion of the curve that will actually print to paper in a straight print. The mid-tones from the scene can be placed properly and as expected on paper using various negs that have been shot anywhere from N to maybe N+3.

    This is scene dependant. It assumes scenes/subjects with normal or narrow brightness ranges.

    This is not some off the wall thought, Jose Villa, Jonathan Canalas and others make a nice living shooting weddings in exactly this manner. Landscape shooters that intend to burn and dodge a bunch to put more of the films curve on the paper may want to be a bit more picky about placement.

    In practical application, the scene's relationship to paper is maintained and the negative and enlarger exposures are simply allowed to float in the middle somewhere.
     
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  23. Athiril

    Athiril Subscriber

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    Then stop using the term saturation to describe hue accuracy.

    In practical application, saturation drops. Hue accuracy also decreases.


    Neither of your posts are actually a response to the central point being discussed.
     
  24. hrst

    hrst Member

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    OK, let's assume this is true to some extent, but up until this point all discussion why it would be so has been on densitometry using false assertions and unneeded complications. What I think is that it isn't just a densitometry (amount of dye per amount of exposure) issue.

    The "compression" you describe is just a description of the basic densitometry, namely the "shoulder". If you hit the shoulder, you are exactly right, but I claim that you usually do not hit the shoulder with today's color neg film with most subjects. The sunset/sunrise is one of the few exceptions. But well the curve isn't perfectly linear but we are not talking about big differences here. There must be some other reason to your experience.

    When we are talking about color saturation, we usually talk about "perceived saturation" which is just contrast, discussed above. Increasing contrast naturally increases perceived saturation and sharpness and vice-versa, but if we are not affecting contrast, then this is not what we are interested in.

    However, the real color saturation is defined otherwise. AFAIK, it is dependent on how wide the absorption peaks of the sensitization dyes are. If they overlap much, a large number of hues can be reproduced life-like because there are no deep "valleys" in the sum of the three spectral curves between the primary colors. But at the same time, "color saturation" is somewhat subdued. OTOH, if the dyes have narrower absorption spectra, color saturation can be increased at the cost of "reality" of the hues. Some hues are now reproduced too light and some hues too dark, but that is exactly one of the reasons why the image looks more vivid.

    But, is this connected to exposure or densitometry in any way? Or is it just a film design parameter that keeps constant regardless of exposure? How the color saturation is controlled when designing a film? Can we affect the real color saturation, not contrast, in exposure choice and/or processing? This is a question that always goes unanswered.
     
  25. markbarendt

    markbarendt Subscriber

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    Each layer in color film only makes one color and it is always fully saturated because there is no other choice. The density is the only variable I see.

    Balancing the exposure of the layers is another story because each layer responds differently, has it's own EI needs, dependent upon the lighting. If there are two subjects lit by differing sources correcting/filtering for balance on one, will skew the balance for the other.

    It is also quite easy to underexpose one layer just in the shadows while shooting at box speed. This makes for a nasty printing problem.
     
  26. keithwms

    keithwms Member

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    LOL my first question as well. Because Rolleis work miracles with shitty light, don't ya know :wink:

    Mustafa, please clarify what you are trying to achieve. Are you trying to put in colour that you didn't see with your eyes at the time? Not trying to be flippant but that's what it sounds like to me.

    Or: is the issue that your film isn't handling the colour temp in low light / shade? That is a common issue with colour film.

    If you want more saturation in flat, low light then you might try slide film, but just be aware that colour temperature can shift wildly from 5000K in low light/shade. You're not going to get daylight tones from any colour film unless you take that into account and filter appropriately. Colours will wash out quickly if you don't.... no matter how you expose.

    That said, I do sometimes mildly overexpose colour neg film to enhance the primary colours and give more saturation. But again, if colour temp is off... is that your issue?

    Rollei has zero to do with it. Not even sure the film has much to do with it, really. This is probably a colour temp issue, but why not show us an example. Maybe I am misunderstanding your issue, sorry if I am.
     
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