@Man, yes smartlighting in higher levels does strange things in the toning of colors.
I use it with boxes in black area and white area in combination with exposure correction. Mostly 25%.
Then it act’s as a flexible black and white point. Moving exc up white get’s supressed so you don’t push white in clipping.
Selective tone does have alot of overlap. Which is a good and bad thing.
I find it depends on the image. Last night, I was working on some older photos that were taken in very low light. Several weren’t exposed correctly, but had the composition I wanted. So how to fill in the right end of the histogram? I tried a few things like you did, Joanna, and found what worked best for me was to raise Smart Lighting to around 50, then highlights, and then either shadows or blacks - whichever keeps the contrast between light and shadow reasonable.
I think I would make the same choices for the image you provided as a test case. Raising only the highlights as much as you did (to 78) left the contrast too high (shadows are still underexposed), while Smart Lighting set to Strong raises the shadows and highlights nicely but keeps the contrast too low for my taste. I notice you didn’t suggest leaving the image like that, but rather, suggested Smart Lighting as a starting point for “making manipulation easier.” I think that’s a good approach, as long as colors are well preserved. Simply lowering midtones a bit after this (or applying some ClearView Plus, which usually lowers midtones in flatter parts of the image) would reach the result I like. There might need to be some manual lifting of the highlights after lowering midtones, as these ranges do overlap in PhotoLab.
Adjusting Contrast sliders after Smart Lighting can also yield some nice results - but I usually keep those adjustments small.
Smart Lighting can fail when the image is severely underexposed or when film emulations are used. (By design, the latter alter the histogram in a way that Smart Lighting doesn’t notice and therefore can’t correct). So sometimes adjusting Color Rendering sliders and settings is very helpful.
I’d like to thank the “pros” for these conversations. This is the information gleaned from years of experience that’s not in the books. Again, thank you.
Thanks for the useful tips. However one thing I find is Smart Lighting often does little-to-nothing on my shots. I am assuming this is because of the actual lighting present in the shot. It’s one thing to have an image with the full gamut of tones from dark to light, but another thing if you photograph coal on snow*. This is one thing I’ve always found odd about focusing on a balanced histogram — the assumption that the scene has all light levels present. A night or very low light scene will naturally exist to the left and a snowy landscape to the right.
However, I do use the histogram as a primary tool to understand what leeway I have when I am trying to fix lighting, along with the clipping indicators.
*No, I don’t photograph that — haven’t seen coal since I was a kid — but I think it gets the idea across.
This is a very interesting discussion, Joanna - Personally, I use your #2 & #3 methods … and I’ve learnt to do so until it “looks right” to me (to the point that I don’t bother with the histogram much at all any more !).
John M
Thanks for your video, Peter - - I always find it “enlightening” to watch how others use PL.
Your use of Smart Lighting reminded me of a gripe (annoyance) I’ve long had with this tool; in that, often, I want to compare the affect of SM Uniform versus SM Spot Weighted - BUT the intensity settings are not “sticky” … I have an outstanding UI improvement request here, for this issue.
John M
Would you not create a couple of temporary virtual copies and compare those?
True, but the first image in aperture mode and shot a “normal” exposed in the middle by watching histogram, not ETTR, the scene i used for first video would be more spread. higlights where possibly still nearclippingpoint due snow. but the gras and shadows where darker more near black.
a wider histogram to begin with. i think, i wasn’t there.
That one was compressed by exposing ETTR. (which everyone would do by the way if you stood there to capture the top and bottom as good as possible, but in this case the “lower anker got drifted”)
Smartlighting does two things:
compress DR in highdynamic scene’s to get rid of clipping warnings. (contrast is low.)
expand DR in low dynamic scene’s to gain some nuance , to be seen in histogram as getting wider more spread.
I suspect it uses the algoritm of selective tone sliders in automatic mode together with contrast and gamma level.
By using two or more boxes to give away which objects ,part of the Dynamicrange, you want to effect you can control the effects better.
And even only effect a part of the histogram.
In some ways, the title I gave this thread could be construed as suggesting that the histogram should always be full - something which is certainly not the case.
Or is it? Take the example of this image…
… and its histogram…
This was made, quite deliberately, as a high-key image so, understandably, there are very few tones in the first half of the histogram and the image appears as we would expect.
However, if I turn on the over and under exposure warnings, I only have to move the ends of the tone curve sideways by a couple of points…
… and both the under and over exposure warnings start to flash.
Especially surprising for the shadows end but, if you look at this section of the flower…
… in more detail, you find that there are indeed tones that are virtually black, despite the apparent absence of such tones in the histogram. It’s all about the scale of the histogram, where there are simply not enough levels to show such small quantities of a particular tone.
In fact, despite its appearance, I have completely filled this histogram 
Virtual Copies are very useful when you want to preserve a particular “state” before moving on to more detailed corrections … BUT, I find them to be next to useless for comparison of subtle differences - because the time it takes to (re)render ALL corrections when switching between VCs exceeds my mental picture of the previous result !
John M
Hmmm. I don’t get any lag on my Mac. For comparison, I choose one of the virtual copies, then I set the comparison drop-down to another and simply hit the Compare button.
That’s really interesting, Joanna - I’ve only ever thought to switch between VCs via the Image Browser - not via the Compare; and I’m most surprised (indeed, curious) to find that the latter is much faster … tho, still not fast enough for me to make a satisfactory mental comparison.
Which suggests that either your Mac is much faster than my PC - - or my mental picture dissolves too quickly 
John
Thanks again for the second useful tip today 
Works like a charm and you pass by the lag when completely switching. I mostly only compare to the original, (pressing “D”), but knowing this now is a game changer. Will use it for sure more in future.
And, thanks for this reminder, KD … I had forgotten.
It’s a bit fiddly to set-up a VC as the reference image (and not at all obvious, on the Win version, that it’s even possible to do so !), but it’s certainly faster to compare VCs this way than it is by switching between them via the Image Browser (PL is obviously caching them).
All the same, I’d still prefer that the SM intensity values were “sticky” !
John
never realised that i had this feature.
Thanks.
When I raised this as a concern last year, DxO explained that the lag disappears once the images have been cached. Sometimes I have to switch between two images several times before they’re both cached and can be displayed just about instantaneously. Especially if they’re from a RAW file. So maybe it would help to raise the size of your cache in your PhotoLab preferences and make sure you have enough free system RAM. I suspect using a fast SSD also helps with this.
Just tried your suggestion and raised the memory from 1000MB to 10000MB. But it makes no difference. Cleared the cache before and opened then 6 editet images. This raised the used memory up to around 6MB. The lag, because of rendering the preview, when switching in the image browser stays the same like before.
You tried switching back and forth between two images several times, and the lag never went away?
Yes I did and the lag keeps. It always starts to render the preview again. On Mac btw.
