Exercise 3: Histograms

A histogram is a pictorial graph which shows the distribution of pixels throughout an image ranging from black on the left to white on the right, the amount of pixels that represent a specific value, from 0 to 255 is represented as a vertical and can be manipulated by using various editing processes with software. This exercise is to increase our familiarity with histograms, explaining and showing there meanings and how they can therefore relate to specific images.

I aimed to produce 3 different images, one each of high, low and average contrast and again each consisting of 3 versions of them, one properly exposed, one a stop higher and again a stop lower.

Low contrast at 0.00

Average 0.00 H Average 0.00

 

Low Contrast at +1.00

Average 1.00 Average 1.00 H

Low Contrast at -1.00

Average -1.00 H Average -1.00

For this images I captured this bird bath in my garden, as it was rather average in contrast, not producing much shadow and again lacking in highlights too, but as you can see with each corresponding histograms that as you boost the exposure it moves slightly to the right and when you lower it, it goes to the left. As this image was initially well exposed there are no resulting clipping at either end.

High Contrast at 0.00

Low 0.00 H Low 0.00

High Contrast at +1.00

Low 1.00 Low 1.00 H

High Contrast at -1.00

Low -1.00 H Low -1.00

With these images having a lot of contrast in, the light colours of the foreground arch coupled with the lights of the window in contrast to the darkness between the two this creates an interesting image with depth. The histogram reflects this by being more compact. As visible in the the first to images, the Highlights in the windows are clipped and in the final image there is less of this coupled with a small amount of shadow being clipped at the bottom of the image.

Average Contrast at 0.00

High 0.00 H High 0.00

Average Contrast at +1.00

High 1.00 High 1.00 H

Average Contrast at -0.00

High -1.00 High -1.00 H

These average contrast images, initially not showing much depth or interest are effected by the change in exposure as shown in the histograms, each one changes considerably giving a higher amount of clipping on the overly exposed image.

This exercise has really for the first time enabled me to focus on the histogram and to understand its uses, properties and potential in understanding the image, however it in most cases be considered a guide as it does not make allowances for your own ideas or aims for an image as a dark and moody image would be considered wrong based on a histogram but not with what you were aiming for.

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