Lightroom - Exposure vs Brightness...

kelly1

Hello, could someone please tell me the difference between brightness and exposure in Lightroom?

Thanks,
Noel.

pixbyjohn

In my simple understanding of it.
Brightness will only brighten the photo, but exposure will recover the information in the dark parts of the picture especially if you are using raw images.

kelly1

PixbyJohn, sounds like you're describing Fill Light.

I think I've worked out the difference.

Looks like Brightness slider shifts the histogram left or right with very little scaling. The Exposure setting seems to shift and scale the histogram like the Levels control in Photoshop.

I don't know why they don't just have a levels control!

Noel.

Heebie

Exposure is very different from brightness... although often does similar things.

With exposure you're taking the entire exposed range of the image and either stretching it or compressing it at the bright end.

If you bring the exposure down, you are taking the "whitest" point, and making it darker.. everything else scales down and gets compressed into the "space" left between the black point and the white point, while staying relative to both of those points. (so.. if you have 15% gray between a black point of 0 and a white point of 100.. it's value will be 15.. but if you take the white point down to 50.. that same 15% gray will now be a value of 7.5 overall instead of 15. If you raise the white point to 200.. the 15% will then be 30. Note..the PERCENTAGE stays the same... this is a relative value with relationships to the black point and the white point. (and.. the values I've used.. 0, 100 and 200 are randomly select and really have no bearing on individual photographs.)

The "black point" in relation to exposure will always be true black.. no color present.

The "black" control lets you adjust the "black point" upwards into the histogram... so say the darkest point you have in your photo has a value of 25.. that means there are no actual blacks in the photo.. just greys. You can "toe in" the black value to "pull" that 25 value down to be true black. This is great if something is looking a bit washed out.

On to brightness.

Brightness takes the absolute values (NON-relative.. NOT percentages in other words) and makes them ALL brighter or darker.

Next to fill-light. This takes only the darkER sections of the photo (generally doesn't go all the way to black) and makes only those sections of the photo brighter or darker. This can be good for getting a bit more detail out of shadowed areas.

Using all 4 of them SKILFULLY can be great. Overusing them can look absolutely horrid. Play with them a bit & see if you "get it"

It's VERY helpful that the histogram is there & edited in real-time.. it will tell you a lot about what's going on.

Heebie

Your description regarding brightness is entirely accurate for showing the effects of the brightness control.. if you take EVERY point and make it brighter.. the whole histogram slides right.. make them all darker and it slides left... without changing "scale"

The control in Lightroom is very similar to a levels control.. but in some ways more complicated..and other ways simpler.

I forgot to mention the contrast control.. which scales the histogram out to both sides from the centre. (similar to the exposure control.. except that instead of scaling from black to the white point you choose. it scales from 50% gray towards both the black & white points simultaneously.

kelly1 wrote: »

PixbyJohn, sounds like you're describing Fill Light.

I think I've worked out the difference.

Looks like Brightness slider shifts the histogram left or right with very little scaling. The Exposure setting seems to shift and scale the histogram like the Levels control in Photoshop.

I don't know why they don't just have a levels control!

Noel.

kelly1

Thanks Heebie. I think it's worth knowing that using the exposure control can stretch the histogram resulting in tonal gaps.

5uspect

kelly1 wrote: »

I don't know why they don't just have a levels control!

You can just a "cranked" straight line adjustment in your curves adjustment to do exactly what levels does. Curves is just non-linear adjustment of the histogram.

kelly1 wrote: »

Thanks Heebie. I think it's worth knowing that using the exposure control can stretch the histogram resulting in tonal gaps.

If you shoot in RAW and convert to something like jpeg then this isn't going to be an issue since you're stripping out the tonal depth anyway.