Highlight recovery

Software PhotoFlow
1

@Carmelo_DrRaw,

Just out of curiousity, how does the highlight recovery feature work in PhF? What visible changes would one expect to see when activated?

I have a long exp shot, with one cloud that was illuminated by the sun on an otherwise cloudy day. Yet, no matter what I do, I can’t seem to make it appear darker without it looking worse than it is.

Thanks!

2

There are three HL recovery options:

  • “none” means nothing is done to the RGB channels, which is not recommended for normal use
  • “clip” means all channel are clipped to 1.0 after the WB multipliers are applied. This is the most basic option and also the default one
  • “blend” uses the same algorithm as the “Blend” method in RT

The effect is better seen when applying a negative exposure compensation to blown highlights, like in those screenshots:

"clip" recovery mode

1920×1175 1.64 MB

"blend" recovery mode

1920×1175 1.69 MB

no recovery

1920×1174 1.69 MB

3

Ahh, so in order for it to work properly, you need to lower the exposure a little?

4

The “blend” mode might also give some visible differences compared to “clip” in regions very close to be blown, because the blending procedure also considers pixels with are near the clipping point.

It really depends on your image and on how smooth are the transitions from bright to saturated…

5

[quote=“Carmelo_DrRaw, post:4, topic:2278”]
It really depends on your image and on how smooth are the transitions from bright to saturated…
[/quote] Hmmm… yes.

I just tried to use the highlight recovery, sent to Gimp, and ran it through auto levels, and while the rest of the pic has improved, the over exposed part has blown out again. How can I fix this?

Pre auto levels (as passed through from PhF)

1920×1080 1.56 MB

After auto levels added…

1920×1080 1.69 MB

blow out seen clearly above the statue… The truth is, the exposure still isn’t bright enough, but as I raise it, the blown out areas become more blown out.

Thanks heaps for your help btw…

6

I personally would not use auto levels, and instead adjust the gamma cursor (the central cursor below the histogram in the levels dialog).

Adjusting gamma will rise the brightness in the mid-tones but keep the white point unchanged, i.e. it will expand the dark tones and crush the bright ones without changing the black and white points.

Another possibility is to protect the highlights with a luminosity mask…