WP Special Effects | Equalize

[MikeG]

The post from Charles2 about Faststone referred to the Equalise transform, which, hitherto, had flown well under my radar. Now I've experimented with it a bit I can see that it has a lot to offer. Is anyone using it on a regular basis? If so, how and for what?

Also, perhaps those who use it on an irregular basis might explain what prompts its use?

Hoping to learn something...

Mike.

[MikeG]

Woops! Title should be PWP Special Effects | Equalize.

[couman]

On occasion, I use equalize in conjunction with an area-based mask to enhance sky contrast.

[MikeG]

Thanks, Bob. That's an application that I hadn't thought of.
From the lack of posts to this thread it may be the case that this transform is little used.

[den]

MikeG....

Here is an Equalize example...

The effect is subtle; difficult to show at posting resolutions; and works best as a refinement to an already near preference, full-range, brightness, contrast, color, 48-bit depth [or 16-bit B/W] Input image.

For the mask, I tend to use a BrokenLine curve with a mid-tone [x,100] control point near/at a histogram peak or near/at a mid-tone histogram minimum between two substantial peaks... 'lower-left' Apply Add; then soften slightly with a 'lower-left' Apply Blur = 1. The diagonals from the [x,100] control point act as gradients to the black point and white point. As the black or white points are approached, the transform has less effect, but maximium effect at the control point. This tends to prevent the deep shadows and the high highlights from loosing detail because of additional pixels due to equalization.

Leave the mask 'active' on the Equalize Input image so that it can be re-adjusted if needed. For some images, the mask white Amount can be 100% but for others the Preview image will go exceedingly dark so a less Amount is needed as was the case for the illustrated example. View Preview in 1:1 resolution as you do when Sharpening.

For the illustrated 'after' example, there is more 'detail' in the foreground water, the mountains, and clouds, evidenced by the increased breadth/slope heights of the histogram peaks.

before.jpg (30.61 KiB) Viewed 5784 times

Equalize-Mask-1.jpg (38.48 KiB) Viewed 5783 times

after.jpg (30.71 KiB) Viewed 5783 times

[den]

Add'l comment...

If there is a visual element or elements whose Input image's brightness, contrasts, and color you prefer [the tugboat or perhaps the dark land mass the peeks out from the histogram/mask dialog overlays] over the transformed image...

...1:1 Clone with a soft-side brush those elements from the Input image into the resulting Equalized image version...

[MikeG]

Thank you, Den, for the example.
I followed your procedure on two images that I shot yesterday. The first I now realise was a poor choice. I've posted below the result of processing using mostly the brightness curve and a mask selecting the plane, and at 50% transparency, the train. Equalise transform produced noticeable vignetting of the blue sky ever at 20%. Just to be clear the first image was NOT processed with the Equalize transform.

1.JPG (47.71 KiB) Viewed 5703 times

The second image proved to be a much more suitable choice. I should mention that the day was rather hazy, and, fairly obviously, I was using a telephoto lens. The Equalize transform did a good job of making the background in particular less hazy and I am resolved to use it for similar photos in the future. Quite often, around the harbour, I'm unhappy with the haziness of the background and I think that the Equalize transform my be a boon in this regard. Incidentally I did use 1:1 close for sections of the warship.
Oh! I should mention, for any who notice how puny and knocked about the warship appears that it is a resident of the Australian Maritime Museum on a day's outing! Here's the image.
Mike.

1.JPG (47.71 KiB) Viewed 5703 times

No idea why the first image has appeared twice - Sorry!

[Charles2]

This winter (northern hemisphere!) I greatly reduced fog from a few images. Heighten contrast in the midtones only. I use BrightnessRGB, don't know whether that is best choice. I like histogram view for this operation. Confine the midtones with two fixed vectors, stretch two vectors between them outward which applies an S-curve. Might need to experiment with different placements to find the range that affects haze and not much else.

[MikeG]

Charles - nice to have a choice of techniques, isn't it? Equalise is a new one for me so I'll be experimenting with that for a while.
Following are firstly an out-of-the-camera jpeg, followed by that jpeg treated only with Equalize. NB I see from Preview that the images are in reverse order.
As I had noticed that the background was towards the top of the image, and I didn't want to do much to the water, I used a vertical gradient terminating at the water line of the warship as a mask for the Equalize transform. Quick - and (to my eyes at least) a decent result.
Mike.