Last week in the comments a request was made for levels and curves by JSolomon, and she said it would be good to do it in GIMP. I know that for most people Photoshop is too expensive and it is hard doing tutorials in it. I tried to contact Adobe about this, but apparently they don’t like people contacting them, especially when you look at trying to do it, and even more so if you manage to contact them, well, it is even harder getting a response. GIMP is free and for most people more than adequate, so GIMP it is.
Doing this tutorial created an interesting dilemma for me, I use both, but I have never really thought about when to use them, I just use them. I know in Photoshop there are certain things you can do, but you can’t do them in GIMP. I had to do some reading. This tutorial is going to be basic, but hopefully will give you enough of an understanding of how they are different and when to use them.
Next right click on the image, go to Colors, then Levels.
This window is used to adjust the levels. The levels adjusts the tonal range of the image. As you can see by the histogram above the red circles I have drawn, the tonal range is spread right over, there is some in the black area on the left and some more in the light area on the right, and not much in between.
This is how I was taught to do levels, you move the arrow, circled in red to the edge of the histogram, like so. The one at the other end would stay where it is because the histogram is right up to the edge. Changing the one for whites, hasn’t done a lot. Time to move the middles one.
I didn’t move it much, but you can see that the pylons holding up the jetty have lightened up quite a bit, but unfortunately when you do this, the whole image lightens up and you start to lose detail in the lights.
This is not a good image for levels, you will never get the image you want from using it.
However, for an image like the one above, it is perfect. The image is quite well exposed, but according to the histogram, needs a little lightening up. So I would move the right arrow to the beginning of the histogram, and the middle one to the left until I thought the image was better.
For our first image, Curves is probably going to be a lot better. With curves you can control more, you have more say in the highlights, shadows and darks. You can change the lights without it affecting other parts. This is where it starts to get complicated.
You can move the start of the curve over to where the histogram starts, like up the top of the line, circled in red. You can almost put a marker on the midway point. This anchors the curve at that spot.
You can see where I have moved the line or the curve here and how it has changed the image. I darkened the sky, and lightened the poles. The only thing to watch out for really is that areas can become too grey. It really is different for each image and you just have to try different things to see how you go.
Both have their places. In the image above, the levels has made the sky too light, whereas the curves has done something strange to the water. Admittedly, it wasn’t a great image to begin with. I think it is a judgement call and you need to decide depending on the image. I usually start with levels, if I can’t get the result I want with that, then I go to curves. If I am fixing up a selected area of the image then I use curves. I say play, and see what you come up.
I hope I haven’t made it all too confusing. It is a tough one. Experience is the best key. Levels is probably the best way to start.
I just experienced something in GIMP that I haven’t come across before, it wouldn’t let me save my image as a jpeg, I will have to investigate that more.
I have almost finished writing the first part in my series on photography. I just to pretty it up some more. Hopefully it will be ready to be sold soon. I thought I would concentrate on taking photos and leave the editing for now. I am hoping there are enough people out there that will be interested in that.
Reality Blog Award
I’ve been nominated for another award, this time from Jenny’s Serendipity,
Thank you Jen.