Selecting bracketed negatives using scanner

I bracket my medium format landscape pictures. Normally I use reversable film like Velvia. So selecting the best shot is pretty easy before the scan (with an Epson V600). You can see which are over or under exposed and select the one to scan.

But I started using color negative film like Portra and Ektar. How do you setup your scanner and decide which of the three braketed shots would be the best to work with? Thanks. Alan.

scan them all and HDR? set them all on a light table and examine with a loupe? scan all three at the same time low resolution and have a look?

Scan them all and see which ones don't have the shadows clipped. The one with the least exposure that doesn't clip the shadows will have the cleanest scan in the highlights. Compare the shadow areas to the film base. You want an exposure that has a slight bit of density over the film base.

How much did you bracket by?
If you only bracketed by + or - 1 or 2 stops, then you will not notice a difference in scans unless you disable autoexposure.

Unlike digitals, most negatives - Portra in particular, has so much latitude that with autoexposure on the scanner set, you will not see much of a difference if any at all as shown below.


Larger version -> Kodak Portra 400 & Ektar 100 and digitals



Even with a "normal" scan, there is so much room for post work with Kodak Portra 400. As shown below, I can use Shadows and Highlights to dig into the shadows and recover highlights.

Larger version -> Kodak Portra 400 Shadows & Highlights


Which Portra - 160 or 400?

Larger version -> Kodak Portra 160 latitude - with post process

Larger version -> Kodak Portra 400 latitude - no post process

Should I quit bracketing then?

well, at least you should quit bracketing using a strategy based on reversal film. I think Les has some good points which should assist your bracketing strategy.

I mainly expose for the rendering of shadows and mid tones on Neg. So I sometimes take another exposure at a different setting "just to see" ... but not much with 120, only 35mm where I don't care if I waste some film.

I quit bracketing with color negative film. After much testing I have just settled on shooting color neg at box speed -2/3 stop (100 for a 160 speed film, 64 for a 100 speed film) and metering to place the shadows on zone 3 using my Pentax digital spot meter. This speed gives me details in the shadows with very minimal clipping when I scan, optically prints well, and still has plenty of latitude for any highlights I am likely to encounter. I get similar results when using an incident meter and about the same with the built in meter on most cameras, so the box speed -2/3 stop works well across the board with how I shoot.

Les: Thanks for posting the tests. From what I see, there seems to be a fairly large difference between -1, normal, and -1 stop especially in the yellow color background of the box itself both in the pre and post adjusted tests. (the bottom two tests). That's what I found in the Portra roll I tried (shooting a landscape picture). There was a distinct difference in colors (blues and greens and even beiges). The thing is that unless you look at all three pictures at the same time, you might not realize the color shift. Since I'm not shooting color ads for clothes where photo colors have to exactly match fabric colors, then it probably isn't critical. I think I'll continue to bracket and see what I get before making a decision on what to do Fortunately, I'm not a big user of 120 film, so cost isn't a factor. Thanks.

Gebhardt: I'm curious about the underexposing. Normally, that's a consideration of reversal film. You don;t want to oveexposureue because lost highlights cannot be recovered. But what is the rational ov undeexposingng negative film. Shouldn't you want to over-expose to pick up the shadows?

Alan, by setting the speed at 2/3 of a stop under box speed you are actually over exposing from box speed. So, yes, you are right; we are over exposing to pick up the shadows.

Alan, I am glad you found some use of the examples. Please consider that it was not my intention to color balance the results and these are from autoexposure conducted by the scanner/software. My intention was to simply show how much latitude it has compared to some digitals I have. As you can see, the digitals are hopelessly unrecoverable at +4 regardless that it is a RAW file and maximum highlights setting. In that first example, I did attempt a recovery and color balance of the Kodak Portra 400 at +10 overexposure using white balance and levels. Additionally, I could have also adjusted the scanner to "burn" it more - in Nikonscan this is Analog Gain from -2 to +2 with a default of 0. I use the analogy as the scanner takes considerably longer to scan which darkens the exposure to some extent.

I find that learning the camera's metering systems - particularly if not spot metering, as well as the individual film's characteristics allows me flexibility. For instance I saw a scene that required f8 @ 1/60 to get proper exposure. However, I wanted to slow down the flow of the water to about 1/8 - 1/4 at the same aperture to DOF but didn't have an ND filter. Knowing that I can easily overexpose Kodak Ektar 100 by +4 to +5 means I can get good results as shown below. Full automatic scan.




Using a single frame of Fuji Velvia 100, below is an example of Analog Gain, Shadows recovery and HDR using 1 frame of film scanned with an analog gain of 0, +1 and +2.

Larger version -> Fuji Velvia 100

Larry: Of course you're right. You are overexposing. That's what happens when I don't pay attention and just bracket both sides of metered exposure.

Anyway, just examples of some digital darkroom work that I've done and of course different scanners, software and film - after the shot is taken, will require further exploration!

Les: Did you process the overexposed waterfall differently or were the changes just made afterwords or both? Nice shot.

Alan, That is a straight up automatic scan using Coolscan 5000+Nikonscan, all color controls off, auto focus/expose with no pre or post anything except for resize and copyright. There were 29 frames on that roll similarly made.