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photography, Tips and Technique

DAILY POST: Contrast on the Bayshore Cutoff.

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A San Francisco Slide Challenge.

I’ve long been intrigued by the short section of the former Southern Pacific Bayshore Cutoff at the old Potrero Wye, where the railroad runs beneath I-280.

This location offers a graphic contrast; the immensity of the highway shadowing the railroad both literally and metaphorically.

The location also poses a photographic challenge. During high light, the tracks are completely within shadow, so I’ve found the best time to photograph is early in the morning or late in the day, when sunlight is below the bridge.

Yet, low sun also poses a problem, as calculating exposure is neither intuitive nor can a camera meter be relied upon. The overwhelming highway structure will tend to result in overexposure as a camera meter tries to compensate for the darkness, yet the side of the train reflects the full brightness of the sun (which to further complicate matters, may be less than sun at midday).

I made this photograph of an inbound Cal-Train ‘Baby Bullet’ in April 2008, using my Canon EOS 3 with a 50mm lens on Fujichrome slide film. I used my Minolta Mark IV handheld meter in reflective mode to sample the exposure on the side of a gray highway support column, and preset my camera accordingly. (I didn’t make note of the exposure, but it was about f5.6 1/500th of second.)

The resulting color slide looks just about perfect, but my exposure/contrast problem was repeated when I went to scan the image.

My first scan of the slide result in this unacceptably dark and contrasty image. Specifically there was compression of the exposure curve that resulted in highlights that are too dark and a serious loss of shadow detail. I'd made this scan using my Epson V600 with the auto exposure 'on'. Obviously to get a better scan, I'd need to take exposure matters into my own hands.
My first scan of the slide resulted in this unacceptably dark and contrasty image. Specifically there was compression of the exposure curve that resulted in highlights that are too dark and a serious loss of shadow detail. I’d made this scan using my Epson V600 with the auto exposure feature ‘on’. Obviously to get a better scan, I’d need to take exposure matters into my own hands.

Here, I found the scanner software’s auto exposure had the reverse problem of my in-camera meter and tended to underexpose the scan. The result was not only too dark, but unacceptably contrasty.

I switched off the auto exposure, and instead used the software’s exposure histogram to set exposure manually as to better balance the highlight and shadow areas. Using this setting, I made a another scan. Afterwards, I fine-tuned the improved scan using Photoshop to make for a more pleasing image by adjusting both contrast and color balance.

This is my second scan. To capture the full dynamic range of the slide, I've broadened my exposure curve manually. Notice that there is considerably more detail in the shadow areas than in the original scan. I've allowed the over all image to appear relatively flat in order to obtain as much detail as possible between the extremes of highlight to shadows. This is an intermediate stage, as the image still doesn't please me.
This is my second scan. To capture the full dynamic range of the slide, I’ve broadened my exposure curve manually. Notice that there is considerably more detail in the shadow areas than in the original scan. I’ve allowed the over all image to appear relatively flat in order to obtain as much detail as possible between the extremes of highlight to shadows. This is an intermediate stage, as the image still doesn’t please me.
I imported the second scan into Photoshop and then manipulated the color balance curve to compensate for an excessive red balance (likely the result of a processing inadequacy; specifically in the shadow areas, possibly the result of very slightly exhausted, or under replenished, color developer.)
I imported the second scan into Photoshop and then manipulated the color balance curve to compensate for an excessive red balance (likely the result of a processing inadequacy; specifically in the shadow areas, possibly the result of very slightly exhausted, or under replenished, color developer) then made a slight adjustment to the exposure curve to make the highlights slightly brighter and shadows a little darker. I still wasn’t satisfied. The image was neither as I remember it, nor as it appears in the slide. So went back to the second scan and made a new set of modifications, see below.
Here is the fourth version of the image, and in my opinion the version that most accurate interprets the scene as I saw it. I've further manipulated the exposure curve to improve the highlight and shadow contrast while retaining detail in both areas. I was also slightly less heavy handed in my color adjustment because I felt that a warmer tone suited the scene.
Here is the fourth version of the image, and in my opinion the version that most accurately interprets the scene as I saw it. I’ve further manipulated the exposure curve to improve the highlight and shadow contrast while retaining detail in both areas. I was also less heavy-handed in my color adjustment because I felt that a warmer tone suited the scene.

This image is an exception; most of the time I’m satisfied with my first scan. Incidentally, the  pictures reproduced here are scaled Jpgs from very large Tiff scans. The file size of the Jpgs is just a fraction of the original scan size, which is adequate for small-size internet viewing.

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