How to select only 100% pure white in AF Photo?

[waxewzt]

Ideally I would like to be able to refine the parameters for Select by Tonal Range/Highlights to define the luminance range for "Highlights".

Failing that is there a way to select all areas that are pure blown out white? or within a luminance range from 250 to 255 for example.

[firstdefence]

You could use the Threshold Adjustment Filter to find the whitest white in the image by sliding the slider all the way over to the right to approx 98-99% then mark the "hotspot" with a vertical and horizontal guide.

If you wanted to pull back on the whitest white so that you no longer have hotspots, you could keep the threshold adjustment filter and add a Shadows/Highlights Adjustment Filter to the image and adjust the Highlights slider to a minus figure somewhere around -5% to--7% or until the threshold filter no longer displays hotspots you can then turn off the Threshold Adjustment Filter.

Original untouched image.

Threshold Adjustment Filter tuned to 98% showing hottest part of the image

Shadow/Highlights Adjustments Filter Tuned to eliminate Hottest Part of the Image

Image adjusted, this is a very subtle adjustment.

[firstdefence]

A post you may be interested in: 

 

[lepr]

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[waxewzt]

Thanks to both respondents to my question. That looks like it will work. And certainly the macros will be most helpful as i an hoping to create a macro for fixing small blown highlights in artwork photography. The macro will produce a blurred layer under a layer with hotspots selected, grown, feathered and deleted.

The hotspots in question are caused by dust embedded in the art surface so pretty small and not practical to manually treat.

Ideally this problem should be prevented at the photographic stage using cross polarization but this is not always possible.

thanks again!

[Roger C]

8 hours ago, owenr said:

I would use a Threshold adjustment in a similar way to @firstdefence: nest a Threshold adjustment inside the image layer, move the threshold slider to at least 98% to make the image black and white with the hottest parts being white.

Cmd-click (ctrl-click on Windows) the image's thumbnail (not its name and not the adjustment's thumbnail or name) in the Layers panel to get a selection of the pixels that have been made white by the adjustment.

Now disable the adjustment to see the image again.

That sounds like an excellent idea. But I can't reproduce it. When I ctrl-click the image's thumbnail the whole image is selected, not just the white pixels.

What simple mistake am I making?

R

(An "Affinity Reaction" for whoever guesses the weather person hiding in the image!)

 

[lepr]

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[Alfred]

31 minutes ago, owenr said:

Sorry. It was my mistake.

Should have written shift-cmd-click (shift-ctrl-click on Windows).

That’s better! For those wondering, Cmd-click on Mac (or Ctrl-click on Windows) selects the non-transparent pixels, but the Threshold adjustment makes the layer black and white rather than black and transparent, so there are no transparent pixels to be left unselected.

[firstdefence]

1 hour ago, Roger C said:

(An "Affinity Reaction" for whoever guesses the weather person hiding in the image!)

John Kettley lol!

[- S -]

3 hours ago, Roger C said:

(An "Affinity Reaction" for whoever guesses the weather person hiding in the image!)

1 hour ago, firstdefence said:

John Kettley lol!

John Kettley is a weatherman and so is…Michael Fish.

"Affinity Reaction" please.  

 

[firstdefence]

4 minutes ago, - S - said:

John Kettley is a weatherman and so is—Michael Fish… 

"Affinity Reaction" please.  

 

 

[Roger C]

@owenr, that works delightfully well! Super useful. Thanks.

How do you and alfred know all these tricks?

------------------------------------------------------------------------------------------------------------------------------------

And now...

... I realise I forgot to write "correctly guesses". As I don't want any virtual litigation, it's Reactions to everyone who had a go.

So, whose loud checked jacket was bursting through the threshold? If you squint hard you can just make out...

Monsieur Poisson himself!

And refreshingly he's forecasting some

traditional British Summer weather.

Well done @- S - !

Your Superpowers make you the

undisputed silver lining of all the

(magnetic) clouds on the board.

R

[R C-R]

@Roger C, since I live in Texas, I do not know anything about Michael Fish or UK weathermen in general, but if the UK is subject to "(magnetic) clouds" your weather must be quite a bit different from what we see here! They must play havoc with compasses, broadcast services, & many other things.