This exercise was all about simulating a linear image. I took an image and converted it to 16 bits per channel ( interestingly, I found that I could not do this in Photoshop Elements 10 and eventually achieved the conversion using Adobe CS4 ). Then following instructions I made a gamma correction curve to match the curve selected for the exercise which resulted in a much darker image ( see below ). As expected the histograms for the two images i.e. original and altered version do differ. In the darkened version the histogram shows how squashed up the tones are towards the left hand side.
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| P500: f4 @ 1/160 ISO 160 11mm |
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| Histogram for P500 |
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| Linear image for P501 |
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| P501 |
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| Histogram for P501 |
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| Linear image for P502 |
The linear image for P502 shows the strong curve required to get back as near as possible to the original image ( P500 ) ...the reverse of the curve for P501.
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| P502 |
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| Histogram for P502 |
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| Histogram for P500 |
While not exactly the same these histograms P502 and P 500 ) are very similar.
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