To see why this is so, compare the histograms of the images. I think the image with the contrast mask has a lot more pop! This one looks kind of flat by comparison. I’ve tried to adjust the contrast to have the leaves appear about the same. It is informative to see how this technique compares to the conventional technique of using the contrast dialog to adjust contrast. The image at top left is the original, the top right is with the contrast mask. Similarly, turn off the Background layer if you want to view the mask to do further work on it. After blurring the contrast mask the overall image should now look much sharper.Ĭlick on the “eye” next to the Contrast Mask layer in the Layers dialog to rapidly compare the image with and without the mask. You will need to experiment to find the best value, but typically a value between 10 and 30 will do nicely. Go to the image window and right-click, selecting: (This step is not strictly necessary, but it is helpful to prevent confusion about what is on each layer, especially if you add some additional layers for other editing purposes). Now double-click on the duplicate layer and rename the new layer “Contrast Mask”. Right-click on the Background layer and select Duplicate (there is also a button for this in the bottom button bar of the Layers dialog. We want to brighten the dark areas a little and darken the light areas a little. At the same time, the yellow flowers have a couple of specular highlights that would probably blow out the detail if printed. The red leaves are a little too dark to make out the detail if printed, the result would be pretty dark and muddy. Here is the original example image, loaded into GIMP. Experiment to see if it can work for your particular image. Occasionally this technique gives unacceptable color shifts in certain images. If you feel your image has exposure problems you might want to consider those techniques as well. The contrast mask technique does some similar things for the exposure as the digital split ND filter and the blended exposures techniques. I adapted it for GIMP from a Photoshop tutorial on The Luminous Landscape web site (great photography web site BTW I recommend it). Giving credit where credit is due: I did not come up with this method. All the while your original image remains blissfully unchanged on its layer. The images are combined in overlay mode: dark parts with light, light parts with dark. The basic technique is to create a layer above the image that contains a B&W negative of the image. You can of course modify your image directly in GIMP to decrease contrast, but the advantage of the contrast mask technique is that it allows you much more precise control, and gives better results. This may be necessary to obtain a decent print, because prints on paper do not have as much dynamic range as a monitor if you don’t control the contrast, detail in the highlights may blow out and detail in the shadows can block up and become muddy or even black. A contrast mask allows you to reduce overall contrast, simultaneously bringing out more detail in highlights and shadows. In this tutorial I’ll show you how to do create a contrast mask for your image in GIMP. Jeschke and may not be used without permission of the author. Text and images Copyright (C) 2002 Eric R.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |