Proposed Filter Preview

Original

Proposed filter

The proposed filter adds a 'cinematic' look to any image by increasing the contrast and saturation of the image. While the image on the left is more accurate than the one of the right, a stylized cinematic look can look better aesthetically (i.e. many cinematographers prefer the aesthetics of film over video). However, the filter does not quite emulate a film look. It avoids the use of RGB curves (inherent to film), as they cause noticeable shifts in hue and saturation.

Basic color enhancement algorithms - mockup from Vegas

Proposed filter

The left image was achieved via the color curves filter in Sony Vegas (a NLE), applying a s-shaped curve to the R, G, and B channels individually. A small amount of saturation was added via the Color Corrector filter (chroma X 1.138). The use of RGB curves tends to de-saturate highlights (i.e. in the girls' cheeks) and increase saturation in the "midtones". Note also that the red/purple shirt on the left does not have the same amount of detail between the different methods.

The s-shaped curve is a similar idea to film's inherent transfer function. Film however has a much wider dynamic range to begin with- this provides different/better results (not shown). Inherent to RGB curves are shifts in hue and saturation - I would argue that my filter exhibits this effect to a much lesser degree.

Is tweaking necessary?

The following comparison shows the filter applied to a set of images. This exercise demonstrates that reasonably good results can be achieved with a single set of settings. Of course, tweaking the parameters for individual images will produce better results.

Original

Proposed filter

Extended Dynamic Range Capture

New cameras are emerging that allow more dynamic range than typical CCIR Rec. 601 video. The Panasonic DVX100 for example has camera settings that allows to adjust its transfer function and gamma curves. The Andromeda modification to the DVX100 allows uncompressed capture and even more dynamic range. With a typical "linear" mapping, extended dynamic range images tends to look 'flat', lacking in contrast and saturation. The proposed algorithm adds contrast and saturation to compensate for this effect.

Original - Andromeda capture (extended dynamic range)

Processed with proposed filter algorithms

The pair of images below shows the benefits of extended dynamic capture versus typical normal/typical dynamic range (CCIR Rec. 601). Extended dynamic range capture allows greater highlight detail. This is noticeable in the white/yellow colored sphere in the background building, to the upper right. It is also noticeable in the sunlit faces of the sculptures and in the building detail along the top facade.

Normal dynamic range

Processed from Andromeda capture (extended dynamic range)

F900 Images

These images are from a Sony F900 shooting low contrast linear.

According to Steve Shaw, his 'Gamma Curves' for the f900 and f950 "will capture LOG, not linear, which is even better, and more like the Viper images, but without the green cast".


Original image courtesy Steve Shaw of digitalpraxis.net


Processed.