Problematic tone after Levels adjustment -

[The View]

To get a photo, that only uses a part of the brightness levels, use more of them, I use the levels tool.

Now I have some images, where the subject is in a darker place, light falls on their face, and the background is rather dark.

If I use Levels to "stretch" the image to take up more use of more brightness levels, I get a higher dynamic.

But I noticed, that sometimes the smoothness of tone transitions seem to be "tearing up".

How do you deal with that?

By not trying to use the full range of brightness levels?

I have no problems if the face is brighter. But if it is a little in the shadow, then I have this breaking up of the smoothness of the shadow tones.

[Panopeeper]

This is the classical case, where 16bit depth is required to prevent posterisation.

[tompappas]

Absolutely, using a high bit depth will help with a smooth tonal transition, especially in the dark tones.  also, doing it as an adjustment layer, and then changing the layer blending mode to "luminosity" will effect only the brightness in the image without the increase in color saturation.

tom pappas

[Jonathan Ratzlaff]

Can you post an example?  Sometimes your video card and monitor play tricks on you and when you print it what looks like posterization isn't there.  This could be especially true if you use an LCD monitor because few of them actually display 24 bit colour.

this has been a fairly rare occurance with my experience and using a CRT monitor.

[The View]

This is the classical case, where 16bit depth is required to prevent posterisation.
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My export options from LR to PS are 16-bit and ProPhoto color space.

I checked that little menu on the left bottom of the image: it says ProPhot 16bit.

So I should be working in ProPhoto 16bit color space, shouldn't I?


Any chances I have some menu item "on" or "off" that could have a negative impact?


Or maybe I am just very particular about light quality in my photos, and a certain loss of quality (IT'S KIND OF A TERRIBLY INCREASED LOCAL CONTRAST) is normal for this kind of levels adjustment.

Isn't this kind of levels adjustment a true Histogram stretching exercise?

[The View]

Absolutely, using a high bit depth will help with a smooth tonal transition, especially in the dark tones.  also, doing it as an adjustment layer, and then changing the layer blending mode to "luminosity" will effect only the brightness in the image without the increase in color saturation.

tom pappas
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I always do it as an adjustment layer.

But if I switch the blend mode to "luminosity" (like I do in curves), I lose almost all color, and it gets quite desaturated.

[tompappas]

I always do it as an adjustment layer.

But if I switch the blend mode to "luminosity" (like I do in curves), I lose almost all color, and it gets quite desaturated.
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Good Morning

What I like to do in that situation is to make a second adjustment layer - usually a hue/saturation adjustment with the blend mode set to "saturation", that way I can really dial in the intensity of the color to my taste.

From what you are saying in the above posts, sounds like you are doing everything correctly - export to photoshop 16 bit, prophoto rgb, adjustment layer etc.  

Sounds like it is simply a limitation of the lcd display.  Have you tried making a quick print to see if the problems are in the output?

Tom

[DarkPenguin]

A 6-bit monitor can give you grief, too.  Dunno what you're using but it if is cheap it might be 6-bit.

[Panopeeper]

My export options from LR to PS are 16-bit and ProPhoto color space

Then some other possibilities:

- your monitor is not good enough, i.e. it can not reproduce all the required levels.
in PS, move the cursor over the posterizing area and look for the RGB values. If you see different values within an area, which appears uniform on the monitor, then blame the monitor

- the color space conversion is causing it (your monitor is certainly not displaying ProPhoto RGB)

- there are not enough levels to start with in the raw data

Isn't this kind of levels adjustment a true Histogram stretching exercise?

It is, but nothing wrong with it, as long as there are enough levels.

If you upload the raw file and the posterizing result, I can take a look at the raw data before de-mosaicing.

[The View]

Thanks, Panopeeper, for the very informative post.

I guess it's not enough levels in this particular shot.

That face was partly in the shadow - less brightness levels.

I will simply do a less stretching levels adjustment with this particular shot.

[Guillermo Luijk]

I will simply do a less stretching levels adjustment with this particular shot.

And with future shots try to make the main subject fall high enough in the RAW's dynamic range (less noise, less posterization).