White Slider

I watch YT-video’s on post processing, some of them based on LR. In many cases the white slider is used.

As I don’t use LR, I would like to know how I can achieve a similar effect/result with Photolab. Is it just moving the white point in curves or something else? Or can I achieve this with smart lightning by placing boxes on certain parts of the image? Or could/should I use the ‘Highlight fine contrast’ slider?

What I’m also trying to say is that even if DXO implements a white slider in Photolab it’s questionable that this will behave the same as in LR. As I understand this also applies for the difference between the highlight slider in Photolab and LR. Same name for a slider but different outcome.

It’s a different process, but, essentially; Yes.

John M

In PhotoLab just try the same thing as shown in the video


pull any slider or the tone curve to see what’s happening

1 Like

Where having a levels tool as well as the curve is useful, is for images that start out like this…

… with a histogram like this…

Capture d’écran 2022-01-22 à 13.28.01

In order to be able to peg the white level, in PL5, I need to move the top of the tone curve like this…

Capture d’écran 2022-01-22 à 13.29.40

… which shifts the histogram like this…

Capture d’écran 2022-01-22 à 13.29.54

… but that now means I have to fit any delicate curve adjustments into 2/5 of the width of the tool instead of the full width, losing out on the ability to do anything complex like your example

1 Like

I have never used Lr and I found it interesting that the “parametric” tone curve seems to do essentially the same as the Selective Tonality sliders in PL, and that there is a lot of overlap in the tones covered by each segment of the tone curve when they are adjusted. I believe having this type of visualisation would have avoided a lot of folks not understanding that the sliders in PL also have such an overlap, which might have to be compensated for.

1 Like

DPL vs. LrC: Same, but different, test it yourself…

Exposure

White Slider

Tone Curve

As you can see, both apps do the same in a slightly different way. Adobe has some hidden additions while DPL acts straightforwardly and aggressively - compared to LrC.

Test file (11 steps ProPhotoRGB):
11-step-wedge.tif (100.8 KB)

1 Like

…not really…

I did a test in PL to see if the black slider has the same effect as moving the black point in the tone curve using a greyscale.

The greyscale has the following equal RGB values:
(0, 25, 51, 76, 102, 127, 153, 178, 204, 229, 255)

Greyscale.tif (1,1 MB)

No corrections applied in PL.

My objective is to adjust the first 3 bars from the left to black, i.e. RGB = (0,0,0)

First adjustment: using Selective Tone, Blacks = -87:
Black slider

Result:

Values: (0, 0, 0, 29, 58, 88, 120, 153, 187, 220, 255)

Now reset the Selective Tone Black slider to zero.

Second adjustment: using the Tone curve by moving the blackpoint to the right until the 3rd bar has RGB=(0,0,0).

TC Blackpoint

Result:

Values: (0, 0, 0, 31, 63, 95, 128, 159, 192, 222, 255)

The differences between using the black slider and moving the blackpoint is:
(0, 0, 0, 2, 5, 7, 8, 6, 5, 2, 0)

Not a major difference but still a difference.

And this would seem to bear out my supposition that the Selective Tone sliders do much the same as the Parametric Tone Curve sliders do in Lr. The great thing about the Lr sliders, IMO, is that they seem to be an alternative method to adjusting the Tone Curve and their effect is shown in the curve, not supplemental to it.

Although, it would take some practice to see if that is a good thing or not.

Maybe a little off-topic, but following the DXO forum for some time I got the impression that it’s common to use the Smart Lighting with the setting on Spot Weighted and placing boxes on the brightest and darkest parts of an image.

I thought it was used to set the white and black point, or at least for defining a good tonal range for the image. And maybe as an alternative for the white slider in LR.

So I took my greyscale, but this time without the 2 bars on the left and on the right. Values from left to right are (51,76,102,127,153,178,205).

Greyscale without first and last 2.tif (731,4 KB)

Then I used the Smart Lighting with Spot Weighted and placed 1 box on the right bar and used the modes slight, medium, strong and 100%. The right bar gets the value of 255 first with the mode ‘strong’.

And the left bar went from 51 to 20.

Because this is not pure black, I’ve placed a 2nd box on the left bar. Hoping this will set the blackpoint.

But the opposite is happening, the RGB values of the left bar are now 42. So instead of decreasing it’s increasing.

I also tested if bigger boxes would make a difference. It does but not what I expected. The RGB value of the left bar has raised to 52.

Now I’m confused what Spot weighted is doing.

I use them to set (better to control) what part of the highlights / shadows should contain some texture.
What you can do in a real pic, not here with the grey steps, pull the rectangle and move it around to see what’s happening …
(and those modes Slight Medium Strong are only presets).

Ok, so Smart Lighting is a kind of shadows and highlight recovery.

But is that also the objective of the white slider in LR?

Because with a slider you can increase of decrease values.

What I see on YT in post-processing when someone uses the white slider is most of the times increasing the values, not decreasing. I think that is not getting more texture, but just adding more contrast in the brightest parts of the image.

After looking at the video and seeing where he talks about graduation of levels within a bar when “selective tone” sliders were moved, I thought I would see what happened to the test image in PL5.

Sure enough, the bars start to show different values from left to right.

Take the example of applying only -100 to the mid-tones slider…

Base 0 42 70 94 119 143 167 189 211 232 255
Left 0 42 59 64 74 97 133 171 207 232 255
Right 0 41 51 59 74 100 136 174 209 232 255

Applying only +100 to the shadows slider…

Base 0 42 70 94 119 143 167 189 211 232 255
Left 0 114 132 142 154 168 183 199 216 234 255
Right 0 96 116 132 148 163 179 196 214 233 255

So, it would seem that this is a way of introducing a subtle extra edge contrast between two adjacent tones.

If anybody has got the time and energy, it could be interesting to see what shape these offsets make when applied to the tone curve.

My base greyscale has the following equal RGB values:

(0, 25, 51, 76, 102, 127, 153, 178, 204, 229, 255)

Using the Selective Tone in PL and setting the midtones to -100, I get the same effect within a bar. For example the bar with base value 127 has the following values for (left, middle, right) = (78, 80, 81).

Using the Tone curve and lowering the Midpoint so that this same bar has a value of 80, then there’s no difference within the bar itself: (left, middle, right) = (80, 80, 80).

TC Midpoint -80

Addendum:

But using the tone curve in PL is a little bit annoying. There’s no picker tool and I can not set the exact (x,y) values of each point on the curve (like the black point and white point). Also missing is a sampler tool to set on a place in the image. Now I have to switch between the curve tool and the hand tool to see the RGB values under the histogram.
Affinity Photo has a better implementation of these tools.

1 Like

Well, who’d have thought we would find out something about PL from a video on Lr? :roll_eyes:

:joy: :joy: :joy: :joy: :joy: :joy: :joy: :joy: :joy: :joy:

I got the message that this post must have at least 10 characters :rofl:

Hi
Interesting test.
Strangely,i don’t have same values measured in PL5. (black line is for me (3,3,2) and white is (252,252,252).
I did a quick test in C1 v20.
Not same measures ( the black is 5.5.5 and white is 253.253.253). I don’t know if default setting is applied, i couln’t find it.

measures give in C1 BEFORE
5.39.68.95.120.145.168.190.212.234.253

with black slider at -100
measures are as follows:
0.0.2.35.85.116.141.165.188.210.232.251

So in conclusion, C1 black slider is more selective than the black slider of PL5.

White slider increase is fairly common. Lightroom, when set to automatic tone correction, often reduces brightness and increases whites in order to keep white things white. The same also happens with blacks: when brightness is raised, black values are lowered.

I found a difference between the ‘11-step-wedge.tif’ of platypus and my ‘greyscale.tif’ (Lex).

The ‘11-step-wedge.tif’ of platypus doesn’t start with (0,0,0) but with (3,2,2) in my version of PL5 on windows. Also the last bar is (252,252,253) instead of (255,255,255).

I’ve checked this also in Affinity Photo: (3,3,3) and (252,252,252):

11-step-wedge (Platypus) check in AP.

There’re other slight differences too.

Which one did you use?

I created the step wedge in PS in Lab colour space and exported it to a ProPhotoRGB TIFF.
Start and end were set to 1% and 99% brightness in HSB.