Setting Black, Gray and White point

[Petar Petrenko]

Hi,

is there any way to set black, gray and white point in Photo just like in Photoshop?

[Gabe]

Hi @Petar Petrenko,

 

I'm afraid we do not have this option. You can hold down ALT while moving the sliders and you should get a preview of the areas that clip. This way you can drag until your black and white areas just clip and you're good to go. 

 

Thanks,

Gabe.  

[Petar Petrenko]

Is there any chances to be added in near future? It is great feature for photographers.

[Petar Petrenko]

https://www.xrite.com/categories/calibration-profiling/colorchecker-grayscale

[Gabe]

I will move this to our Feature Request section 

[toltec]

17 minutes ago, Petar Petrenko said:

Hi,

is there any way to set black, gray and white point in Photo just like in Photoshop?

 

 

I sort of simulate that with a curves adjustment.

 

Use the Picker.

 

Click on the area to be black and drag to the bottom.

Click on the area to be white and drag to the top.

Click on the area to be grey and drag to the middle.

 

The curve allows some very good fine tuning.

 

Sorry but this is not great because it was a totally unsuitable image to use but it was all I had to hand to show the points.

 

 

 

[Petar Petrenko]

But how to adjust to be 18% gray as in the xRite link I sent?

[toltec]

1 minute ago, Petar Petrenko said:

But how to adjust to be 18% gray as in the xRite link I sent?

 

It doesn't. It just sets the black, white and mid grey points. Like using the Photoshop eyedroppers.

[Petar Petrenko]

5 minutes ago, toltec said:

 

It doesn't. It just sets the black, white and mid grey points. Like using the Photoshop eyedroppers.

 

Yes, I like them too. You can set the gray level to any percentage you need via "Options..." and they can be found in "Curves" beside "Levels".

[toltec]

36 minutes ago, Petar Petrenko said:

 

Yes, I like them too. You can set the gray level to any percentage you need via "Options...".

 

I used to use them all the time, that's why I started using the curves adjustment to simulate them.

 

What you could do is combine it with using the Info panel.

 

Set an "info" target on the 18% grey checker area

 

Use a Curve adjustment layer and user the picker to set the black and white points. Click on the 18% grey area with the picker, then move the curve point until the info panel shows 18%,

This curve was the result from a screengrab of the x-rite link ColorChecker thing.

 

It's not perfect and is a slightly messy workaround but better than nothing ? The curves adjustment does allow great fine tuning though.

[Petar Petrenko]

Yes, I agree with you. I'll give it a try for sure. Thank you very much for this woraround.

[Petar Petrenko]

As you can see I, somehow, managed to set the gray to 18%, but how to adjust black and white points? Would you be so kind and explain to me in more details?

[toltec]

1 hour ago, Petar Petrenko said:

As you can see I, somehow, managed to set the gray to 18%, but how to adjust black and white points? Would you be so kind and explain to me in more details?

 

 It is best to do the black and white points first.

 

Using the Curves Picker, click on the area that appears to be (or should be) pure black. When you click, drag down to the bottom. You will see the histogram change.

 Set another point, this time on a point that should be pure white, and drag up to the top. Look at my curves panel grabs to see the position of the points.

 

Now set the grey.

 

It might be a good idea while you experiment to set an info target on all three points. White, grey and black so you can see what you are doing. Once you have done a couple, there will be no need. The curves histogram reveals all 

 

This curve is a bit odd on the grey because of the adjustments you made.

[Petar Petrenko]

Thank you Toltec for being so patient with me, but it is SF for me. Better to wait Affinity to manage this at some point in the future.

[vinde simone]

I'm not sure my method is 100% right, but I think you might check and decide:

 

1. Add a fill layer and fill iti with 50% grey, then set it to Difference.

2 Add a Threshold layer, then move its cursor all the way to the left until  you'll get your picture completely white.

3. Move the cursor towards the right and stop when you see the first group of pixels turned black and zoom with cmd+9 on it-

4. Activate the Info panel and put a marker on the first pixel turned black.

5. Turn grey and Threshold layers off; now you can see that the pixel under the marker is actually almost grey 50%. You can check its color code in the Info panel; let's say,, for instance, its color is 130, 120, 120.

6. Since you want it to become exactly a 128,128,128 pixel you have to add a Curve layer and set it to RGB mode, then you have to click on the Selector button and…

7.1. In the Curve floating window, select the red channel, clic on the marker on the picture and correct its value by dragging until R turns from 130 to 128.

7.2 Correct the other two values the same way, by turning G and B values from 120 to 128.

8. If the result is good for you, delete grey and Threshold layers and merge the picture and curve layer. That's it.

 

Please, give me your feedback if you guess my method is helpful, but especially if you check that it doesn't work at all.