[Irma]

I understand that when you have in your histogram colors touching the upper part of the graphic those colors are blown out? I don't know if I am right or not.

Anyway, some of my pictures have this problem and it is very difficult to correct. Someimes in LR with a bit of exposure and some times with desaturation. At the end you don't have the colors you want. When I am shooting I don't know how to correct the problem with more or with less light, with different light or changing my settings to different wb.

Any comment to help me understand this would be greatly appreciated...

[StudioJ]

Less light, different wb, both will help. I find it happens to me quite a bit in the red channel and looks rather ghastly. Sometimes lower contrast will help as well.

[Irma]

Thanks SJ for your comment. I will try that. You are right, the red looks bad.

Really lovely to see you around...

[ADK_Jim]

The histogram is actually a bar graph divided into 256 segments. That number was derived from the limits of computer displays. What the histogram graphic shows is the curve created by the tops of the 256 bars. Each bar represents one of the 256 available tones. The height of any point on the histogram indicates the number of pixels at that tone. You can actually have the curve extend above the top of the graphic in a high key or high contrast image with no tones blown. Where you run into trouble is when the histogram curve exits part way up one or both of the sides of the histogram graphic rather than dipping to the base on both sides. That indicates that there are tones above and/or below what the computer can display. If it exits on the left side (rather than at the base) you have lost shadow detail. If it exits out part way up the right side, you have lost highlight detail. The higher the line exits through the side the more tones you are losing. Exception: If you are shooting RAW and using a good RAW conversion you may be able to recover some of these details since the sensor records slightly more than the 256 tones your computer is limited too. The amount you can recover depends on your camera and the conversion software you are using.

ADK Jim

[Irma]

Thanks a lot Jim....

Last time I took pictures of those yellow lilies I had hard time with the color. I tried with a blue cloth on the umbrella... the color got a bit better, but still it changed.

[wulinka]

well, couldn't you always try to shoot at a shorter exposure and recover some of the detail from more shadowy parts of your picture?

I find that RAW has better detention of detail in highlights, but if you find your highlights too blown out to recover good tones, why don't you try the other way round?

Sorry if I completely misunderstood you...

Uli

[Irma]

Sorry, just a post and go...

This is one of the problems I have...





The thing is that whatever you do in raw the colors are touching the top in the histogram. The picture was taken with flash.

I will be back with more examples with pictures and histogram.

BTW Uli, I am missing you a lot, and your pictures too. I hope you get your computer right soon...

[NT73]

That's too technical for me.

[Pavel]

Hello Irma,

I think I understand the situation (let me know if I do not). I beleive that you basically overexposed your photo. When you see the histogram all buched up to the right and if the rightmost barr is very high, that is what you did. The sensor is basically overwhelmed by light and so it records everything as "white" and thus you do not have details and you have all sorts of strange things happening to your colours. If the overexposure is slight, use the "recovery slider in the LR and Adobe will try to reconstruct the missing bits based on the information it has. This can be successfull to a degree. You can also try to reduce brightness or exposure or contrast and all these actions have a tendency to move the right end of the histogram to the left. This means in effect that your highlights are reduced.

The solution to this problem is in the way you do your metering. From film days, you are used to meter for neutral graay average and you hope for the best for highlights and shadows. With digital photography, you have an option to "meter for highlights". What you do is you meter for the brightest part of the photo you still do not wish to be blown. This could be sky, white frame of the window, white cat etc. Next you overexpose slightly, so that your meter shows + about 1/2 f-stop or so. You take the photo and check the histogram. The rightmost column should not be there, but you should have data coming close tpo the right end of the histogram. What you are doing in effect is getting as high an exposure as you can, without blowing the highlights. In LR, you "fill light" until shadows loose their darkness. On the histogram, you will see that the leftmost part of the histogram is no longer spilling into the leftmost column too much (It is often OK to allow some spill to the left, it just means that you loose some shadow detail, but this is often pleasing). This is probably the most effective method to deal with very contrasty situation, short of using fill-in flash or D-lighting (if you own recent Nikon) or HDR. Let me know if I understood your question correctly and if my explanation was comprehensible. Pavel

[Irma]

The pictures where I had this problem more often were the ones I took with flash. I have changed a bit my light setting and the problem has gone. I think I had my light too strong and direct to the subject.

Thanks a lot Pavel for your explanation.

[Zig]

I wonder....
I think this may be an auto-flash problem...in other words the conversion is not the remedy...or am I being too far out here??

Are you using Canon ETTL flash by any chance? If the answer is yes, it might be worth going manual with the flash...alllegedly(well, Rufus has had a mare of a time with this recently...your post jogged my memory...

[Kombisaurus]

I understand that when you have in your histogram colors touching the upper part of the graphic those colors are blown out? I don't know if I am right or not.

I think Irma you might be mis-reading the histogram...

You are correct in saying that when colours touch (or get clipped at) the upper part of the graph then the colours are blown out. Unfortunately the confusing thing about this statement is that the "upper part" being discussed actually means the right-hand-side edge of the graph, not literally the top edge of the graph. It is talking about the upper part of the x-axis (which is to the right side of the x-axis).

The y-axis represents the number of pixels that fall into each "brightness zone" if you like... This axis is always normalised so that the highest value touches the top of the y-axis. This means that in every photo, you will have some point of the graph touching the top edge.

So in all the examples you posted, none of the highlights were being blown out because there was nothing running off the right-hand edge of the graph. The fact that all the examples touch the top edge is just normal.



In the example above, this photo uses most of the available dynamic range quite well without blowing the highlights (off the right edge) or losing them to shadow. (off the left edge).

While a histogram certainly has its place, personally I think a bit too much emphasis is put on it. Some of my best photos have blown-out highlights or detail lost in the shadows and that's just the way I like it. Sometimes what you don't include is just as important as what you do. I use the "clipping warning" feature to blink areas of the photo that are in danger of being blown out or lost in shadow so I can tell at a glance if I'm content to lose them or not, but apart from that I tend to trust my eye more than a histogram.

Having said that, a histogram can still be handy. Particularly in some not-so-obvious situations where just one or two colour channels get blown out, such as shooting into a very bright (and very red) sunset. It's very easy to blow out the red channel and sometimes the green channel too in a sunset shot which can upset the colour balance. This can be repaired to some extent by using a channel mixer layer, but using the other channels to replace detail in a lost channel is only an estimate of what was lost, so it's not perfect.

Hope that helps?

[Kombisaurus]

Just as a further example Irma, here is a photo that has massively (and deliberately) blown highlights in it so you can see how the histogram is bunched up hard against the right edge.

[Irma]

Thanks Zig,

With the pictures I posted the first histograms I used a studio flash with umbrella. Most of my studio photography I make it with this light because I can place it around any place I need. It has a very long cabel. I always set my camera in manual. But you are right part of this histogram this way was the light.

Thanks Kombi for your comment.

Studying my pictures when I had this kind of histogram, I realized that it was due to the background. When I had a background with an even color the bar appeared in the histogram. If the background was bright (not blown out) the bar was more into the right, when the background was dark the bar was at the left.




This somehow made me think that eventhough I wanted to light my subject only at the right the background didn't correspond well because I had too much light there. What I did was to reduce my light in this case from f14 I went to f20 as I can't work with high sync with this flash, my background had a gradient (light/color) giving better sense of depth to my picture, and the bar was not there.