I talked things over with my photolab recently. I had shot two rolls of B&W at a wedding where I was shooting digital color with my Nikon D300 bodies. Like in the past, I gave the B&W a generous exposure and I told the lab to develop it and to make me a disc. Well, the disc showed overexposure. I tried my usual tweaks in LR2 but I was still over a bit over on some but mostly all. Well, the lab said they don't project thru an enlarger anymore (since three years ago). They recommended that I just shoot the film at the recommended ISO unless I was projecting and printing the B&W at home because they digitize the B&W and therefore, there is no need to overexpose it as in the past as I shoot it.
I was wondering, what is the sense of shooting B&W now if I have to pretend that I am shooting slide film and be very careful with my exposures?
Their scanner can certainly get the image right with over exposure. If they were making a photo disc for you, they were already using whatever scanner at that time (unless they've changed scanners). Photo discs didn't ever come from the optical enlargers. In all likelyhood, they have probably changed something about the scanner or its operator. Either they were doing auto correct before, or they've done something to lock down the scanner now. If the negatives are workable, I would ask them to rescan the disc as the results are unacceptable. If not, there are other labs who will custom scan for you.
It would certainly be acceptable to shoot +1 on standard B&W negative film and then compensate in scan or print, but you have to also realize that you are pushing up into the highlights and there may be negative consequences.
I tend to agree with them though. Unless you are specifically trying to achieve something by overexposure, I would not do it. But there are times when you may wish to use overexposure, so I'm not against it.
Overexposing by one stop doesn't hurt, really, especially with negative film. However, the lab's crappy scans won't pull any significant detail, no more than what is needed for a 4x6 print. Most minilabs these days scan the film, then project it onto chemical paper with lasers. That part is standard. I'd suggest getting something like a Epson V750, or even a used 4490 and scanning it yourself. You'll get far better results.
williamkazak wrote:
I was wondering, what is the sense of shooting B&W now if I have to pretend that I am shooting slide film and be very careful with my exposures?
For the same reasons you always be careful with exposing B&W film, quality of image. Yes, it is possible to salvage an grossly overexposed image that out be practically unsalvagable if shot with color neg or especially color transparency, but there's I pretty big price to be paid. Grain gets worse and acutance suffers. Tonality goes out the window.
Why are you overexposing to begin with? How much are we talking about? I would think the lab's scanning equipment should be able to handle as much as a stop overexposed, but not much more.
What kind of B&W film are you shooting? Is it chromagenic? My experience is you really have to overexpose it to cause scanning problems.
T-Max 400. I was surprised that the lab wanted me to get my exposures tighter when I saw the disc. I am making another test because I like to shoot my F6 and I like the B&W grain.
William, T-Max 400 is imo better at 400 than 200, depending on the developer the lab used TMY can block in the highlights. Best to develop it in T-Max developer as that holds down the highlights. I can see how it would block enough not to come through on a scan. With Tri-X you almost had to have it at ISO320 or 200 to get shadow detail, overall density was less too, it was hard to overexpose Tri-X. this is where the overexpose b&w negs came from. T-Max 400 is a totally different film, if you want grain switch to Tri-X, T-Max has much less grain. Tri-X is more forgiving with developers too.
Right. I forgot all of that. I knew that I liked T-max when it first came out and I used it then. I remember that I had always given Tri-x overexposure.
williamkazak wrote:
T-Max 400. I was surprised that the lab wanted me to get my exposures tighter when I saw the disc. I am making another test because I like to shoot my F6 and I like the B&W grain.
I concur with others that TMax tends to block up faster. Just for grins, you could try T-Max 3200 exposed normally. I was going to recommend a chromogenic film since they really scan well, but you won't get much grain from them.
williamkazak wrote:
I should probably try another roll at the correct ISO and not the 200 set to 400 mode.
If you push the film from 200 to 400 then you're telling the exposure meter that you're film is more sensitive than it really is and so don't need as much exposure. You will be UNDER exposing your film right?
The best solution for determining exposure is to simply look at the negatives under backlight. Next time you shoot film shoot a series of shots bracketing the ISO speed higher or lower than the rated speed on the box. On an optimally exposed negative the darkest areas with detail (e.g. a black suit) should register a density slightly above base+fog (the edges of the film).
Three variables affect highlight density:
Exposure: If you over expose the highlights and shadow densities both rise. Most of the response curve is linear when plotted in the standard DlogE format, so the overexposure doesn't affect contrast between shadow and highlights (i.e. density difference on neg) until 2 or more stops of over exposure pushes the highlights onto the shoulder area of the curve.
Assuming optimal exposure of the negative (deepest shadows just above base density) changes in scene range affect highlight density. If you expose the same scene on clear and overcast days for the shadows to be black, then the negative from the sunny day will have more density in the highlights because more light hit the film during the exposure based on the shadows, The density of the highlights is also affected by development time and temp with conventional developers. The shadows develop rapidly but in the highlights the greater the action of the developer (longer time / higher temp) the more the density will build in the highlights. In the zone system we played one off against the other to keep the density range of the negative a constant, so any scene, regardless of luminance range, would fit the range of a #2 grade print paper.
The limiting factor for contrast isn't the negative, its the print. Because of the linearity in the negative overexposure doesn't change the contrast allowing an over exposed negative to produce a normal print by simply increasing the exposure time of the print paper. That will not work on a scanner because the intensity of the scanning light source is fixed. That's why for scanning you want an optimally exposed negative in the Zone System sense of placing the darkest areas of the scene just above film base + fog.
As noted scene range will cause highlight density to fluctuate. Ideally you want the worst case scenario such as a very contrasty sunlit snow scene with a dark cave in it with a black bear in the cave to fit the dynamic range of the scanner. So to determine the optimal development time for the negatives for scanning you'd want to shoot a scene which a similar range (bear optional) then try different development times until you found the one which allowed the scanner range to record detail from light shadows on the neg. to densest highlights; fitting the range of the negative to the range of the scanner.
A friend who shoots film for scanning recommends Diafine developer:
http://www.bhphotovideo.com/c/product/1064-REG/Acufine_DFD128_Diafine_Developer.html
Diafine Developer is usable over a wide temperature range with one developing time for all films. Fast, medium and slow films can be developed simultaneously without adjustment in developing time. Diafine is unsurpassed in it ability to produce the greatest effective film speed, ultra-fine grain, maximum acutance and highest resolution.Time and temperature have no practical effect if the minimum recommendations are observed. Diafine is an ultra-fine grain developer with the highest effective speeds.
"Back in the day" when I was in a photo school in the Netherlands, we had to do an extensive test to determine our effective exposure:
Find a static subject with exactly 5 stops from the deepest black that still showed some detail to the brightest white with detail and take 5 shots: -2, -1, 0, +1, +2 exposed. Do this five times. Each strip of five negs were then to be developed individually at the same temp, concentration and agitation, but with different developing times: -20 sec, -10 sec, "recommended", +10 sec and +20 sec. This gives 25 different negatives. Technically, only ONE will give the correct dynamic range on paper No. 2 with normal developing. That negative then determines the effective exposure. Quite simple, or what?
Oh - my fave combo: Tmax 400 in Rodinal 1 + 50. I love the way Rodinal puts a little punch on that grain.
Marcel VanEerd wrote:
"Back in the day" when I was in a photo school in the Netherlands, we had to do an extensive test to determine our effective exposure:
Find a static subject with exactly 5 stops from the deepest black that still showed some detail to the brightest white with detail and take 5 shots: -2, -1, 0, +1, +2 exposed. Do this five times. Each strip of five negs were then to be developed individually at the same temp, concentration and agitation, but with different developing times: -20 sec, -10 sec, "recommended", +10 sec and +20 sec. This gives 25 different negatives. Technically, only ONE will give the correct dynamic range on paper No. 2 with normal developing. That negative then determines the effective exposure. Quite simple, or what?
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Yes, but only for studio lit scenes with a range of detail of 5 stops, which is quite low compared to most outdoor scenes. As outdoor scene range changes so does the highlight density and range of the negative. That's what the zone system is all about.
Shadow values on negatives are affected by exposure, but not by development time variation. Thus its far more efficient to nail down optimal ISO speed first, then find the dev. time needed to match scenes of 8 -12 stops to the #2 paper. With testing we determined the development time for the neg. needed to keep the range of density between Zone 1 shadow detail and Zone 8 textured highlights constant and equal to the range of the #2 paper as the scene range changed. Scene with 8 stop ranges would be developed longer than a "normal" 10 stop scene range, and high contrast scenes of 12 stops developed less.
Being lazy and having different tools than Adams did, I adapted the zone system to roll film and multi-contrast paper using a color enlarger. I found the optimal ISO and development for a "normal" 10-stop scene on #2 grade paper and used them as my constants. Scenes of greater or less than 10 stops in luminance range, measured with a 1-degree spot meter would be noted when shooting. They would produce negatives with varying ranges of density in the highlights.
With testing using a calibrated transmission gray scale I had determined the filter pack in my enlarger's dichroic color head needed to fit any negative density range to the poly contrast paper. Magenta light makes the paper more contrasty (for thin short range scene negs) and yellow light makes the paper less contrasty (for heavy long range scene negs,). By mixing yellow and magenta filtration the paper could be made to match a wide range negative density ranges caused by varying scene ranges. By that time I'd also acquired a very nice Ilford enlarging meter which allowed me to read the actual range of the projected negative in density units (.3 D = 1 f/stop) so I was able to determine, quantitatively, the actual range of each negative.
I'd soup all the negs the same way, then make a standard contact sheet filtered for #2 with the baseline ZS print exposure: the minimum time needed to create max. black on the print. Then by looking at the standard proof sheet I could tell at a glance is exposure was correct and what the scene range was relative a "normal" 10-stop range scene. For printing I'd put the neg in the enlarger, meter the density range with the Ilford, refer to my chart of test results on the wall, dial in the filtration needed for that range, adjust exposure using the meter then make a print which would have a full rich tonal range. Print making was much easier that way.
