16mm lighting question
Posted 17 May 2006 - 08:41 PM
My last question concerns my confusion with overexposing the negative and then "printing down." If I'm correct, would I shoot the color chips rating 7205 at 125 ISO (overexposing 1 stop) and then does the lab (using the chips) compensate for the overexposure by printing the negative down while developing? Is this the same as pull processing? Or is it something done in telecine? I know this has probably been asked a lot, so I apologize and, as always, appreciate your knowledge and feedback. Thanks!
Posted 17 May 2006 - 10:51 PM
You have to understand that there are many variations possible -- it all depends on the look you want, and how dense you want the negative to be.
Overexposing a negative and processing normal will result in a denser-than-normal negative. Remember that an overexposed image on a negative is darker, denser overall, and of course the darkest areas correspond to the brightest areas of the real (positive) image.
Overexposing a negative and pull-processing by the same amount (let's say, overexposing by one stop and then pull-processing by one stop) will result in a negative with normal density.
Underexposing and processing normal will result in a thinner-than-normal negative (less dense).
Underexposing and push-processing by the same amount will result in a negative of normal density.
All these approaches produce different results in terms of graininess, contrast, black level, color saturation, etc. and will affect how you print or transfer the image.
Typically, you want the benefits of a slightly overexposed negative that is developed normally so that the negative ends up slightly denser-than-normal. So you rate a 250 ASA stock at 160 ASA, let's say, and process normal. So now your processed negative has a 2/3-stop overexposure; the timer printing the negative can then print that image at higher-than-normal printer light numbers (printing "down") to reduce the brightness of the image down to normal. The colorist transferring the negative will just darken the image to look normal in brightness. It helps if you shot a grey scale at the head of the roll at the same level of overexposure so that by adjusting the image of the grey scale to look "normal" by bringing the brightness down, the following footage on the roll would also have been brought down to normal as well.
Now you could overexpose the negative by one stop and then pull-process by one stop to end up with a negative of normal density. You get the benefits of less graininess, but also you tend to get a lower-contrast image with softer colors, and the blacks are normal. If you had overexposed by one stop and processed normally, then printed the image down to compensate, you'd also get less graininess, but you'd have deeper blacks in the print, which tends to make the colors look more saturated. The contrast may even look higher because of the deeper blacks, a snappier image. I'm talking about printing here; there are fewer benefits to an overexposed negative for a telecine transfer, although you still get less grain and better shadow information -- but the black levels are more a function of the electronic color-correction, and on some telecines, if the negative is too dense, you start to get noise in your highlights because the negative is so dark (dense) in those areas.
Too much overexposure and the opposite starts to happen in the print -- instead of a snappier image, because now you've put too much picture information on the shoulder of the characteristic curve, the gamma starts to flatten out, the contrast gets lower, and you lose highlight details. You also may hit the top of the 50-point printer light scale, making it harder to balance the colors.
Posted 17 May 2006 - 11:02 PM
Posted 17 May 2006 - 11:04 PM
"Printing down" refers to changing the printer lights to make a darker print image from the negative. This step is separate from the development of the negative.
Push- or pull-processing refers to over- or under-developing the negative to restore a normal density (effectively the "brightness") to the negative.
I think what you're thinking of is overexposing the negative for extra density and processing normally, then "printing down" to yield a normal-looking brightness on the print.
The TELECINE process has nothing to do with printing; it strictly refers to the transfer of the image to video. You can still overexpose the neg and process normally for extra density, and then set up the transfer for a normal-looking brightness.
In either case (print or telecine) you would shoot an 18% gray card overexposed by the desired amount, and that image becomes the brightness reference for the lab color-timer or telecine operator.
For your iinteriors you'll have to decide how warm you want "warm" to look. I would start with 3/4 CTB on your tungsten lights if you can afford that much light loss. You could even shoot your tungsten light "clean" if you wanted and then adjust the color at either the printing or telecine step. Just be sure to shoot your gray card under the color of light that you want to appear "white."
Posted 18 May 2006 - 12:29 AM