Do labs make adjustments?

Discussion in 'Film and Processing' started by paul_clayton, Oct 18, 2004.

  1. Is the photograph you take with print film, the same one your get
    back from the lab after developing.

    What I mean, is do all labs make adjustment for over/under exposure?
    If they do, with print film being quite forgiving, then in order to
    bracket, should braketing be done by more than 1 EV?

    THe reason why I ask is that I bracketed a series of three photos of
    the same scene, by +/- 1 EV and all three prints looked identical.

    Any ideas?

    Paul
     
  2. Generally, most labs will make some kind of adjustments, often done automatically (eg auto contrast etc).

    It is possible to request no adjustments - a good lab should be happy to accomodate, but you may have to wait longer to get your prints.
     
  3. Labs have to make adjustments for color balance and exposure for prints from color negatives. If these are machine prints, the adjustments are automatic. Exposure is generally an average exposure adjustment based on the entire image. The goal of the print equipment is to give you consistent exposure, so bracketing exposure when you take the picture will not show much difference. Your camera does someting similar to determine the exposure of the film. If you are taking a picture of a snow scene (lot of white), your camera will generally underexpose the scene. Increasing the exposure by one or more stops will give you a much better exposed negative, which will allow you to get a better print, but it will require custom printing (not machine print) to get the best print.
     
  4. If you bracketed a shot plus or minus one stop with print film, a closer inspection (with a loupe) of the neg and print should reveal a difference in the lighter and darker densities. To get a handle on all this, I suggest you run a simple test by bracketing a rather dark scene and a rather bright scene, but go several HALF stops over and under to exaggerate the effect. A regular photofinisher will attempt to correct the various exposures, but you'll soon SEE the difference. One stop either way is well within the toleranceof most negative films.
     
  5. Yes. And in my experience, getting them NOT to is a majorly uphill battle. As Art says, the negs will tell. Alternatively, shoot a McBeth card on the first frame and tell them to calibrate ALL shots on that. You stand a (slightly) better chance of them complying than telling them not to adjust, simply because there is no non-adjusted setting on the minilab machines and by definition someone has to make the decision of how to expose and color balance, be it machine or human. What you want is for them to apply the same unique setting to all prints of the film.<p>
    In this learning process, I also started to be able to decipher the codes printed on the back of the prints that look like a series of 00, 01, -1 etc. Have them explain their setup, and you'll be able to read on the print back what adjustments they made; density, color (each) etc.<p>
    Or much simpler: shoot slides.
     
  6. What film? Some respond quickly to 1-stop overexposure with more
    shadow detail, others have plenty of shadow detail to begin with.
    In my testing, the print film that changed most at +1 EV was Fuji
    Superia/Press 1600, which showed greatly improved colors at EI 800. The film that changed most at -1 EV was old NPH, which already seemed
    too slow at EI 400. Reala and 400UC change very little at -1/+1,
    even looking at negatives with a loupe.
     
  7. The film I do not notice any difference with is Superia 100. Anyway, bearing the above in mind, I do some experiments and will braket by +/- 1.5 EV.

    In responce to Nicola, if my output requirement is prints, then why use slides?

    The only reason why I asked the question is that I don't see any difference in the prints. But maybe the lab compensating for over/under exposure is a good thing.....

    Also, is the compenstaion made in the prints only, or actually on the negs?

    Paul
     
  8. WHy use slides? Because the feedback (and learning from it) is foolproof: the slide never lies. Furthermore, chances are the lab that's doing your printing from negatives couldn't give two hoots whether you give them a slide to print or a negative. In either case, it's a scan that's made - the paper NEVER sees the negative.<p>
    Your bracketing is correct (for color negative film), it's the feedback you're getting from the prints that doesn't allow you to judge which of the three exposures is best, unless you get good at reading negatives directly on the lightbox. If all you want in return is prints, don't touch a thing. If you want prints AND to learn which exposure was the best: slides and print from slide.
     
  9. And yes, only the prints are adjusted. The film receives the exact same development for the entire roll.
     
  10. Paul, compensation is in prints only, not negatives (although some
    minilabs run "hot" meaning they overdevelop). With Superia 100, you
    should be able to see highlight burnout at +1 because it is a very
    contrasty film.
     
  11. If you make your own prints, they never lie to you!

    OTOH, you can ask a lab for locked beam prints and all prints will be done at a fixed standard exposure time, so you can see over and under exposures for what they really are.

    Ron Mowrey
     
  12. Usually the lab will correct for under and over exposure so it will be difficult to see the differences between the prints, but that is usually the idea to get back 36 prints that are correct or pretty close. If you really want to see what you camera is doing then shoot a couple of rolls of slide film for fun and you will clearly see the diffences of exposure and color tempurature too.

    Getting locked beam prints or fixed time fixed filtration prints made is another option as Rowland suggested. But you made find that some labs are just not willing to do this. While I worked as a cruiseship photographer we would print all of the studio portraits using the fixed time fixed flitration method we would make a couple of tests to find the right filtration and density and then print all the rolls from the same studio set up for those found settings that way we did not have to worry about the printer trying to compensate for red dress shots containing alot of black or white clothing and it usually worked very well but then it should because every thing was shot under the lights so the exposure was consistant throughout the whole shoot. It would also be painfully obvious if a photog had changed the lens apeture by mistake during the shoot as those prints would then come too light or too dark and have to be printed again.

    Just to note we would have 2 studios set up in different locations and they would require different filtration settings. One studio was in a rather narrow are area with white walls on both sides a blue backdrop silver reflective ceiling(out of shot) and blue carpet(out of shot) the other was in a lounge with gold refelcted ceiling no walls either side and dark brown carpet and dark brown backdrop. Filtration was adjusted to give the best skin tones obviously it was amount of light reflecting from the surrounding that caused the different filtrations. I give this example just to show that if you go down the road of fixed print settings what works in one situation may well not work in another.
     
  13. I don't understand why they are unwilling to leave the auto-exposure feature off of their machine.

    Nicola, you are only partially correct. Not all labs are using all digital processes. There are still many labs with the traditional optical method of exposing paper. For these, an ND filter is used to adjust light intensity, not a scanner.
     

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