# Exposure Vs Brightness



## JClishe (Dec 30, 2011)

I'm having a hard time wrapping my head around the difference between the exposure and brightness controls when working on an image in post. Specifically, the brightness control. I completely understand exposure, but I can't come to grips with why you would need to alter brightness after exposure, blacks, fill, and recovery have all been performed.

Can anyone help me out?


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## WesternGuy (Dec 30, 2011)

Jason, here is my understanding - I am assuming you are working in Lightroom (maybe true for Photoshop - don't know) - the Brightness slider is something like a midtones adjustment slider.  If you drag it to the right it will brighten up the midtones and if you drag it to the left, it will darken them up.  The Exposure slider, on the other hand, works on the image as a whole.  I find that I often use this (Brightness slider) when the skies need to be darkened up a bit, i.e, they were washed out - now it doesn't always help, but sometimes this works.  Often, I find that I may have to re-adjust the Exposure slider to brighten things up.  You should be able to see the effects of this from changes in the histogram.  HTH.

Cheers,

WesternGuy


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## Big Mike (Dec 30, 2011)

I'm not 100% on this, but here's what I think...

When you adjust the exposure slider, it changes the 'brightness' evenly.  So the blacks get brighter by the same amount as the mids and the whites.
When you adjust the brightness slider, it is like grabbing the middle of the tone curve and moving it up.  In other words, it starts by brightening the mid tones, leaving the black point and the white point alone.  I think it's similar to adjusting the middle 'triangle' in the levels command in Photoshop.  

So what I do (and what I think is the recommended procedure)...in Lightroom, adjust the exposure slider first, then adjust your recovery & black sliders.  In Photoshop, I'd start with levels and adjust the left & right 'triangles' to change the black & white points.  Then, if needed, I'd adjust the middle slider (or the brightness slider in LR).  Although, I tend not to use the brightness slider in LR, preferring to go to the tone curve and pulling the section of the curve that I want to adjust.


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## KmH (Dec 30, 2011)

According to Bruce Fraser and Jeff Schewe in Real World Camera Raw with Adobe Photoshop CS5: Photoshop CS5's Camera Raw, and Photoshop Lightroom 3's Develope module use Adobe Camera Raw 6. So the info in this book applies to both.

The Exposure slider controls the mapping of the highlight tone values in the image to those in your designated working space (ProPhoto RGB is recommended), but it's first and foremost a white-clipping adjustment.

Brightness is a non-linear adjustment that works very much like Mike said, like the gray input slider in Levels. The Brightness slider lets you redistribute the mid-tone values without clipping the highlights or the shadows.

Another way to adjust mid-tones is found in the Presence section of sliders by using the Clarity slider.


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## jwbryson1 (Dec 30, 2011)

Okay, what about brightness versus fill light in LR3?


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## Big Mike (Dec 30, 2011)

I believe that fill light brightens from the shadows, where as brightness brightens from the middle (as mentioned above).


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## JClishe (Dec 30, 2011)

That helps. The dots still aren't connected yet, but getting closer.  I'll need to find images to play around with. Thanks,


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## Dominantly (Dec 30, 2011)

I never ever touch brightness. Fill and levels are a better bet IMHO.


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## JClishe (Dec 30, 2011)

Dominantly said:


> I never ever touch brightness. Fill and levels are a better bet IMHO.



I like that answer better


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## morethanasnapshot (Dec 30, 2011)

I agree with many of the answers above and previously haven't used brightness in lightroom either.  However, I read somewhere that its useful for making adjustments for prints.  You can use all the other sliders to make your image look good on the screen but when it comes time to print your image it often comes out dark.   This is because your screen is obviously going to be brighter than paper so making a small brightness adjustment can help get rid of dark prints.

Gary
morethanasnapshot.com


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## djacobox372 (Jan 2, 2012)

"Brightness" brightens all the pixel values evenly, light and dark.  This; however, is not optically correct as light falls off quadratically, and there's also the whole gamma curve thing to deal with. 

Exposure biases the brightening/darkening in a way which is more representative of what a change in exposure would have create had it been done when the picture was taken.


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## Garbz (Jan 3, 2012)

morethanasnapshot said:


> I agree with many of the answers above and previously haven't used brightness in lightroom either.  However, I read somewhere that its useful for making adjustments for prints.  You can use all the other sliders to make your image look good on the screen but when it comes time to print your image it often comes out dark.   This is because your screen is obviously going to be brighter than paper so making a small brightness adjustment can help get rid of dark prints.



Calibration alert! Danger Mr Robinson Danger!

For comparing monitors to prints you should artificially limit both the brightness and the contrast ratio, and then light the print brightly with a source of similar colour temp to your monitor. ... That's if its deadly important to get it accurate.


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