Basics for beginners - DPChallenge Forums

Canon EF 28-135mm F/3.5-5.6 IS USM

07/06/2005 11:42:29 PM · #1

My object here is get the beginner started in presenting a better image. There are many image enhancers and many tricks by the way of tools in your typical image editing program. First, I want you to forget about the play box and concentrate on one concept that will yield a better photo off the bat! No fancy or advance filters will make a bad image look better.

I am talking about the levels adjustment. Its finer counterpart is the curves, but curves requires extensive study. Levels, on the other hand, is easy to use and understand. I will simply wet your appetite and hope you will invest a little time to study it further on your own.

The histrogram can be viewed as a linear representation of the tones in your image. You have absolute black on the left and absolute white on the right. There is a center arrow and this is referred to as the gamma adjustment.

First, let us try to understand the mechanics. A healthy histrogram begins its build up on the dark and slopes off at the right. It is like a mountain. If the left starts off midway of the mountain it means that your image lacks detail in the lower tonal values. If you see a rush at the right, where the mountains does not end but is cut, then your image is suffering at the high end.

The easiest conditions to solve is where the histrogram starts a little late from the left or too early on your right. Remember, you are looking at the distribution of tonal values. To understand this more fully we need to introduce the Zone System. We are not going to employ it, but rather to use it as a reference. Zone 1 is total darkness. Zone 2 you are able to discern some detail. Zone three, while still dark, you are able to see enough detail to avoid ambiguity in what you see. Zone 4 approaches almost to full detail of texture. Zone 5 is the center and most images have more Zone 5 than any other image. Zone 6 texture begins to lose a little detail, but all is still good and very appealing. Zone 7 along with 6 have all the lighter areas of the image. Zone 8 is where the lightest part reside. Zone 9, while very light there is still a hint of texture but all info is very unreliable. Highlights are represented here. Zone ten is total white so all detail is lost here. As you can imagine an image can take advantage of the entire spectrum while others will suffer.

So, we are looking at an image that is dull. The histrogram shows that the dark starts very late and the lights end too early. We take the little left arrow and drag it so that it meets the start of the left mountain. The image grows darker at once. We now take the arrow on the right and move it to just where the mountain ends. At once the image jumps out at out. What you have done is to have repositioned the markers to create a new distribution of the light and shadows in your image. The image looks better but our motion on both ends have cause the gamma to shift. Now, and only now is your good taste required. If you drag the gamma to the right the image will frow darker, to the left it will grow lighter. However, you are affecting the midtones here, that is zone 4,5 and 6. Find the best placement and you are finished.

There are some images which start okay on the dark side but then you noticed that the right ends too soon. All you need here is to drag the right arrow near enough to touch the end of the histrogram. Then you leave the dark alone and again adjust the gamma as described above.

To me, levels is the most important adjustment tool because everything else is useless if your basic image is not represented in its best light. This is the tool to master and until you have mastered it, avoid playing with the other tools.

A good way to practice is by uploading good images and then study their histrogram. Then play with the adjustment and observe the results.

The next item to master is curves. Levels allow you to control zone 1,2,3 on the left and zones 8, 9 and 10 on the right and the middle tones with the gamma. Well, curves is more exact because you are able to select a specific zone and adjust it independently of the other tones, as you can surmize, you can easily get in trouble. I will address it in the future. Meantime concentrate on levels. Master it and your images will sing at once.

Message edited by author 2011-04-05 00:43:15.

PhotoRyno

Canon EOS-5D

07/06/2005 11:57:59 PM · #2

What a GREAT post. Although a few questions. When you select levels you have a choice such as Normal, Luminsoity, Color, etc. Which is the correct choice?

Also when you then move to brightness/contract and then hus/sat, what selection do you choose, Normal, Lum, etc. etc.

graphicfunk

Canon EF 28-135mm F/3.5-5.6 IS USM

07/07/2005 12:18:49 AM · #3

In the beginning we always go with normal.

Bear_Music

Samsung Galaxy S21, S21+, S21 Ultra

Sony 24-70mm F4 Vario-Tessar T* FE OSS

07/07/2005 12:27:52 AM · #4

Great post Funk. Hat's off to you.

Ryno, stick with "normal" for one simple reason: anything else is illegal in basic editing. Once you've mastered tools in normal, then you might try playing with other modes.

Robt.

nico_blue

Canon EOS-5D Mark II

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

07/07/2005 12:29:19 AM · #5

great post dan! you have always been amongst one of the most helpful and supportive people here on dpc :-)

@PhotoRyno - i didnt really understand your question but if you mean adjustment layer blending mode then i always do normal but you should def. play around with them, its not like there is a right or wrong setting, it all depends what you are trying to achieve. Only normal is legal for basic editing rules though.

totaldis

Canon EOS-400D Rebel XTi

Canon EF 50mm f/1.8 II

07/07/2005 12:34:50 AM · #6

great post indeed....... my mind hurts though, your zone three is the only zone with the number spelled out. it killlllllls me! boy is it late =)

megryan

Nikon D300

Nikon AF Zoom-Nikkor 80-200mm f/2.8D ED

07/07/2005 12:37:35 AM · #7

no doubt about you graphicfunk ...you're truely an asset to this site !

-Lisa

sheapod

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

07/07/2005 12:38:49 AM · #8

What a truly wonderful post! I have no problems with the levels adjustment, but as graphicfunk stated, I find it pretty easy to get into trouble with curves. I'm nowhere near mastering it. I look forward to the post on that subject.
Thanks for the clearly written and easily understandable explanation.
- Laura

rasdub

Nikon D70

Nikon AF-S DX Zoom-Nikkor 18-70mm f/3.5-4.5G IF-ED

07/07/2005 12:42:49 AM · #9

Just wanted to say thanks for the great information and advice.

Dave

Samsung Galaxy S21, S21+, S21 Ultra

07/07/2005 01:14:19 AM · #10

Originally posted by graphicfunk:

A healthy histrogram begins its build up on the dark and slopes off at the right. It is like a mountain. If the left starts off midway of the mountain it means that your image lacks detail in the lower tonal values. If you see a rush at the right, where the mountains does not end but it is cut, then your image is suffering at the high end.

THANK YOU!

Mainly, i'm confused about the mountain idea. how can it start off "midway of the mountain"? i thought it was the mountain?

Here's my histogram for my current circle image. maybe you can give me examples related to this?

Bear_Music

Sony 24-70mm F4 Vario-Tessar T* FE OSS

07/07/2005 02:07:34 AM · #11

Originally posted by mikala:

Originally posted by graphicfunk:
A healthy histrogram begins its build up on the dark and slopes off at the right. It is like a mountain. If the left starts off midway of the mountain it means that your image lacks detail in the lower tonal values. If you see a rush at the right, where the mountains does not end but it is cut, then your image is suffering at the high end.

THANK YOU!

Mainly, i'm confused about the mountain idea. how can it start off "midway of the mountain"? i thought it was the mountain?

Here's my histogram for my current circle image. maybe you can give me examples related to this?

nova

Canon EOS-6D

Canon EF 35mm f/1.4L USM

07/07/2005 05:23:36 AM · #12

Lots to absorb here, Daniel. Thanks very much for taking the effort to post this, I'll make good use of it. Thanks you too, Robert, for your reliable help for us beginners. Hat's off to you both.

Ray

jaxter

Canon EOS-400D Rebel XTi

Tamron AF 75-300mm f/4.0-5.6 LD for Canon

07/07/2005 06:32:48 AM · #13

Very well written explanation of levels adjustments. Am looking forward to the type up on doing curves.

woohoopepper

Nikon D70

Nikon AF-S DX Zoom-Nikkor 18-70mm f/3.5-4.5G IF-ED

07/07/2005 07:31:35 AM · #14

Nice tutorial grapicfunk. I'll also await your curves explanation, because I have an awful time with that.

Strikeslip

Canon EOS-5D

Canon EF 100-400mm f/4.5-5.6L IS

07/07/2005 07:47:19 AM · #15

Thanks Funk!
:-)

mystical_princess

Canon EOS-5D

07/07/2005 08:03:24 AM · #16

Thanks, really need to learn this stuff!

07/08/2005 01:46:12 AM · #17

In this histogram your mountain starts on the laft (dark) side with a high, skinny peak, and the bulk of the pixels in your image are WAY on the right side of the histogram. Meanwhile, there's a slow slope-off to the bright side, and a sudden spike right at the end.

I deduce that this is the histogram of an already-shopped imageyes, that's right where you've maniulated the tonalities, but I may be wrong on that. I can say with confidence that it's a darkish, moody picture with quite a bit of absolute black.

In a "normally distributed" histogram, the slope starts at far left, very low, rises slowly but with increasing speed to a soft hilltop in the middle, then slopes off in a mirror of the left side to the right. Sort of a classic bell-curve shape.

Wait, I just noticed that's the histogram of the LUMINOSITY channel. Set it to "normal" and cap that, for comparison, okay? You're in much murkier waters with a luminosity histogram.

Thanks Robert! I am trying to find the 'normal' histogram but only find the luminosity option when i choose IMAGE --> HISTOGRAM in PS6. when i choose ADJUST --> LEVELS i get a histogram with only RGB (and the individual colors) as an option. i can't find 'normal' :( i am in rgb mode, could that be the problem?

thanks for your reply, it helped me to 'get' the mountain concept. for some reason i was thinking the histogram would start out at the peak and slope down :O

Samsung Galaxy S21, S21+, S21 Ultra

07/08/2005 01:47:38 AM · #18

Bear_Music

Sony 24-70mm F4 Vario-Tessar T* FE OSS

07/08/2005 02:17:24 AM · #19

Mikala,

Take a look at your histogram:

See the box at the top where it says "Luminosity"? There's a down arrow there? Click that and you will get a list of channels, pick "normal".

Robt.

Canon EF 70-200mm f/4.0L USM

07/08/2005 02:27:12 AM · #20

Originally posted by bear_music:

See the box at the top where it says "Luminosity"? There's a down arrow there? Click that and you will get a list of channels, pick "normal".

Robt.

Robert, I don't get a 'normal' choice. i'm in PS6, here's a copy of another one with the pulldown menu showing...i'm confused.

cpickett

Canon EOS-350D Rebel XT

07/08/2005 02:45:14 PM · #21

I think he just means the histogram that is under (at least in Photoshop CS) "Image -> Adjustments -> Levels". It doesn't say normal, it should say RGB (possibly CMYK if you have your image in that mode).

graphicfunk