Levels Tutorial

[ricktas]

What are ‘levels”?
simply, levels are the range of tones in your photo from deep black to pure white. A photo that covers the full range, but isn't blown out (to bright) or to dark is more visually appealing than one that isn’t. This is not to say that a dark photo or a high-key photo cannot be successful.

THIS IS A BASIC LEVELS TUTORIAL, IT DOES NOT FULLY COVER ALL ASPECTS OF LEVELS ADJUSTMENTS.

In Photoshop, to access the levels adjustment screen, click Layers > Adjustment > Levels Adjustment, on the pop-up screen, just click OK.

http://www.ausphotography.net.au/staff/tutorial/Levels/good.jpg

In the Levels histogram above, the left is the darker tones, the right is the lighter tones. For more information on reading histograms, click here (http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml).

A good histogram should begin in the bottom left corner, arch up and then come down and finish in the bottom right corner. Mostly though, there will be jagged peaks and troughs, rather than a smooth curve. A histogram with all the data bunched to the left is an under-exposed photo, one with all the data bunched to the right is an over-exposed photo. The above is an example of a good histogram.

A levels adjustment can be handy when there is empty space at either end, before the graph starts to climb.

There is no such thing as a perfect histogram.

http://www.ausphotography.net.au/staff/tutorial/Levels/under-and-over.jpg

The above levels histogram shows a photo that is both under-exposed (note the big peak on the left edge) but also parts of the photo are over-exposed (see the peak on the right end). This does not mean it’s a bad photo; it just has very dark and very bright elements to it.

http://www.ausphotography.net.au/staff/tutorial/Levels/under-exposed.jpg

The above levels histogram shows a photo that is under-exposed. Notice how the right end (the highlight end) is devoid of data in the graph. You can correct the levels of this photo by dragging the small white triangle (under the right end of the graph) in towards where the graph data starts to appear on the right.

http://www.ausphotography.net.au/staff/tutorial/Levels/over%20exposed.jpg

The above levels histogram shows an over-exposed photo, generally when the over-exposure is to this extent, the photo cannot be salvaged. To correct Levels here, the left (black) slider needs to be dragged in to the graph left side start. It is worth considering a possible black and white conversion, as mono photographs can look amazingly effective with over-exposed areas. The gaps in this histogram were the result of a small JPG version of a photo. JPG compresses filesizes effectively, but is a 'lossy' file format. Meaning that each time the photo is resaved it loses more data. The gaps in the above histogram show the missing data that JPG compression causes, effectively.

How to adjust the Levels
Underneath the histogram are three sliders, a black one on the left, a grey one in the middle and a white one on the right. By moving these sliders you can perform a levels adjustment. What you need to do is drag the black one in till it lines up with the edge of where the graph data starts to rise, the right one in to where the graph data starts to rise on that end, and if you want to adjust contrast, adjust the middle slider.

It is a simple process of moving those sliders inward to the edge of where the graph starts to rise, creating a range of tones in your photo from black to white. A levels adjustment can do wonders to the final outcome of your photo.

Below are some examples of a photo and its histogram, showing a before and after adjustment.

Under Exposed Photo:
http://www.ausphotography.net.au/staff/tutorial/Levels/shokan%20dark.jpg

Levels histogram for above:
http://www.ausphotography.net.au/staff/tutorial/Levels/shokan%20dark%20levels.jpg

Levels adjusted photo (right slider*white one* moved inwards to touch edge of graph)
http://www.ausphotography.net.au/staff/tutorial/Levels/shokan.jpg

Levels histogram after adjustment of sliders:
http://www.ausphotography.net.au/staff/tutorial/Levels/shokan%20ok.jpg

I HOPE MEMBERS FIND THIS BASIC LEVELS TUTORIAL HELPFUL IN THE PROCESS OF IMPROVING YOUR POST PROCESSING.

[MattC]

Thanks Rick - very helpfull - I have always wondered what that middle slider did - now I know!

[MrJorge]

Nice writeup Rick.

[sixfootfour]

"one with all the data bunched to the left is an over-exposed photo"

Possible typo, shouldn't data on the right be overexposed?

[ricktas]

"one with all the data bunched to the left is an over-exposed photo"

Possible typo, shouldn't data on the right be overexposed?

Ah, thanks, I always have trouble with left and right. Comes from working in medical. We call them as they are to the patient, so we talk about left, meaning patients left, but its our right. Always stumps me. Will fix

[sixfootfour]

Ah, thanks, I always have trouble with left and right. Comes from working in medical. We call them as they are to the patient, so we talk about left, meaning patients left, but its our right. Always stumps me. Will fix


...riiiiight *mental note* do NOT go to see ricktas for that leg amputation!

[Jackaroo]

Thanks Rick for the explanation. I am a little confused with your left and right. Is the comment under the jpg histogram correct - cant seem to get my head around what you are trying to say

[ricktas]

Thanks Rick for the explanation. I am a little confused with your left and right. Is the comment under the jpg histogram correct - cant seem to get my head around what you are trying to say

Thanks, fixed!

[The_Camera_Poser]

thank you Rick- this is on my list for this vacation to learn.

[MTV]

Another great tutorial! Could have saved me a few images back when I was having issues getting my exposures right!

[Trigger Happy]

fantastic tut - I've been trying to work out what to do with these little things and now I know. :)

[NikonNellie]

Thanks Rick - I knew how to adjust my levels but I never knew what the gaps in the histogram were when you adjusted your jpg files.
Oh ....is that why I used to get my left and right mixed up? I too used to work in the medical field.

[dbax]

Just to add to Ricks excellent tute, Using CS3 if you hold the alt key while adjusting the black/white sliders your photo will go either black or white and you can see the detail beginning to appear as you move the sliders.....cool:cool:

[TOM]

Excellent tutorial.

With landscapes and other certain types of images, I like to drag the left slider slightly to the right of where the graph starts to rise. This gives punch to the image and creates a similar look to Fuji Velvia 50 (in conjuction with other adjustments), which has narrow latitude and tends to clip shadows.

[bigbikes]

Nicely written Rick.
One day Im going to learn how to use these. I just need some extra time to sit down and work on it.
Thanks Rick

[NikonNellie]

Nicely written Rick.
One day Im going to learn how to use these. I just need some extra time to sit down and work on it.
Thanks Rick

That's the hardest thing - finding the time!

[jamalnic]

Thanks Rick, a very helpful explanation.

[marko]

Great little tutorial :th3:
Yet another handy notch I can wear on my photography belt thanks to this site.

A question though: When practising this on some of my old under exposed images, I noticed that certain objects such as night lights etc blow out and detract from the image when the levels are adjusted.

Is there an accompanying adjustment, ie: Brightness/Contrast that can be used to limit this?

[ricktas]

Great little tutorial :th3:
Yet another handy notch I can wear on my photography belt thanks to this site.

A question though: When practising this on some of my old under exposed images, I noticed that certain objects such as night lights etc blow out and detract from the image when the levels are adjusted.

Is there an accompanying adjustment, ie: Brightness/Contrast that can be used to limit this?

There is, its the curves adjustment, which is accessible via the menu, right near levels. Curves are a bit more complex, and I haven't written a tutorial on them at this stage.

[wazzam]

Thanks for the great tutorial Rick.


Just to add to Ricks excellent tute, Using CS3 if you hold the alt key while adjusting the black/white sliders your photo will go either black or white and you can see the detail beginning to appear as you move the sliders.....cool:cool:

I just tried this and I'm amazed. You can see exactly when you are starting to blow the highlights. Great tip.

[lourdes]

Thanks Rick, good tut.:th3:

[Miaow]

Thanks for this Rick, Great tutorial :)

[draco]

very nice tutorial.. easy to read, easy to understand.. thanks Rick :D

[nouveau1]

Couldn't find an answer to this one in the thread, so forgive me if someone has already answered this, but...
Doing the RAW work (in my case in Canon DPP) obviously alters the histogram when one comes to look at it in the RGB. What are the advantages/disadvantages of manipulating the images in the two different ways?
Any info appreciated..

[ricktas]

Any alteration to your photo is going to adjust the histogram. I am not sure what you mean by the two different ways?

[nouveau1]

thanks for reply..

I may have misunderstood something here as I think(???) the histogram I'm seeing in the DPP raw tab might actually be a luminance histogram, not a levels one. I guess (?) this would make sense as this histogram can be used to manipulate over/underexposure by shifting the whole curve (+/- 2 EVs), not sliding the dark or light levels as in your tute (which I incidentally found very useful).

I'm not explaining this very well, I clearly don't understand it well enough yet.

Thanks

[ricktas]

AH, yes there are several ways to change histograms and differing software allows differing changes. You maybe comparing the photoshop curves adjustment, with the levels one. I reckon your DPP software has something like curves adjustment as well.

[nouveau1]

i forgot to complete the thought (?dementing); so, the questions i'm asking become;
1/ what are the advantages/disadvantages to manipulating exposure using the raw luminance histogram vs the RGB one?
2/ are there other useful things one can do with the luminance one (IF that's what it is) in RAW?

[ricktas]

I am not familiar with DPP so maybe someone else can answer that one.

[nouveau1]

thanks anyway! i'm learning heaps from your site..

[jev]

1/ what are the advantages/disadvantages to manipulating exposure using the raw luminance histogram vs the RGB one?
The raw luminance histogram allows you to manipulate the dynamic range of the image (compare it to the "levels" tool in other software) - it mainly allows you to set black and white point. There is no gamma manipulation possible, but you can do some contrast adjustments. Note that this histogram is not linear, it is logarithmic!

You ask about exposure - always adjust that in the raw luminance tool because that allows editing at the full dynamic range.

The RGB histogram takes the output of the RAW processing step and manipulates that in terms of output range. It works more like the curves tool in other software.

[nouveau1]

The raw luminance histogram allows you to manipulate the dynamic range of the image (compare it to the "levels" tool in other software) - it mainly allows you to set black and white point. There is no gamma manipulation possible, but you can do some contrast adjustments. Note that this histogram is not linear, it is logarithmic!

You ask about exposure - always adjust that in the raw luminance tool because that allows editing at the full dynamic range.

The RGB histogram takes the output of the RAW processing step and manipulates that in terms of output range. It works more like the curves tool in other software.
Just read this today and do appreciate reply. I have been mucking around (DPP) with an image with high dynamic range and wonder, if you have the inclination, would you be willing to comment if I posted them? - just 3 images; the original from the raw into jpeg, a raw luminance adjusted and then a 3rd using RGB curves/levels (DPP again). It may help me (?other newbies too) understand the software possibilities a little better...

cheers, rick

[ricktas]

Rick, you would need to post them into member photos area, for critique. The tutorials area is not a place for photo reviews. So post them in the relevant photo area stating what you want feedback on etc, and you will get it.

[etherial]

I think I know what Rick (nouveau1) is getting at here, as I think I have the same question.

It appears to me that these levels adjustments are very similar to what you might do with Adobe Camera Raw with a raw image? (Or any other raw image tool for that matter)? DPP is similar in that you can drag the edges of the histogram in and ACR uses the numerous sliders to do effectively the same thing. They all just have subtly different terminology or ways of displaying these controls.

Am I right?

[ricktas]

Yes Mic. Levels adjustments can be performed in DPP, Camera Raw, Lightroom, Aperture, Picasa, Gimp, etc etc. They all work similarly, but may have different icons etc for the various functions and the nomenclature for those functions may also differ.

[etherial]

Ok so I'm on the right track. Would it be safe to saw where possible do your levels adjustments in the raw form and if all you have is jpg or tiff, use PS and the method above?

Now then, curves is another story yes? ACR can't do curves other than some minor adjustments with saturation etc. Whereas PS can do curves adjustments with much more flexibility yes?

(DPP has another tab for doing curves adjustments which could account for the confusion earlier in this thread).

Curves I have no idea...I look forward to that tute when you get the time!

Cheers,

[ricktas]

I tend to do a general check of the histogram in my RAW software(Lightroom) and occasionally make adjustments at that point. Ultimately it is about getting the exposure right in-camera, well as right as you can, and then work wit it in the editing software of your choice. All the adjustments and changes you make to your photo while editing it in PS or similar can affect the histogram, so it can be worthwhile re-checking your histogram (and levels) towards the end of your work-flow as well.

[Chilli]

Just to add to Ricks excellent tute, Using CS3 if you hold the alt key while adjusting the black/white sliders your photo will go either black or white and you can see the detail beginning to appear as you move the sliders.....cool:cool:

Thanks for this tutorial Rick and thanks for this amazing tip dbax.....wowww !

[Elvie]

Thanks Rick, that helpful advice is very much appreciated. Elvie

[mish13]

Thank you everything is starting to make sense to me now.

[Warren Ackary]

Makes note: Learn photoshop and leave Lightroom for awhile.

[etherial]

Makes note: Learn photoshop and leave Lightroom for awhile.

Why is that? Lightroom is far easier to master than Photoshop.

[ricktas]

Makes note: Learn photoshop and leave Lightroom for awhile.

Lightroom has a histogram and you can adjust levels in it too.

[Warren Ackary]

Ta... gave me an insight to Photoshop abit more than I had