Showing posts with label photo. Show all posts
Showing posts with label photo. Show all posts

2014/09/19

Vintage photo style in Gimp

I was seeking for some way how to make a vintage effect to photos in Gimp. I discovered several tutorials and combined them together to something that works for me. Here is the recipe mainly for me not to forget it.

  1. Create three layers in the picture and fill them with colors. Listing their attributes from top to bottom in the Layers window:
    • Some "computer" blue color, the one like in old Dos times. I used 0949e9, Opacity around 17. Layer mode Screen.
    • Some pink color around e865b3, opacity 20, layer mode Screen.
    • Light yellow, like yellow paper for taking notes. My color is fbf2a3, opacity around 60, layer mode Multiply.
    • Now goes the original layer.
  2. Increase contrast to something around 21 in the original layer.
  3. Slightly decrease Hue (-9), increase Lightness (+9), and lower Saturation (-30).
  4. You can further add dark corners. Create a new layer right above the original picture. Use Eclipse selection tool to select the whole picture. Feather selection by reasonable amount of pixels (depends on the photo size, I use 150-400px). Invert selection and fill the corners with black. Set the layer opacity as desired.

More glares can be added by a separate multiplied layer with white and yellow color paintings.

2011/12/04

My Gimp Magic

I'm a Linux user (distribution-agnostic) so I have to bolt my seat down in the airplane but once done, it is really comfortable. The same thing applies to Gimp. Today I spent some time with it on a fresh installation and found out all the good plugins I ever used. The important point here is that there are only three of them to do what I really need. And, of course, all of this can be done manually in a clean Gimp installation but it might take ages.

Contrast Blending aka HDR Photography

High dynamic range imaging is a set of techniques that allow displaying images with big differences between dark and light parts on a limited device. A limited device is a usual computer screen or a printed image. None of these media can fully display the range that a human eye is able to see. So we need to make a compromise in the scene.

There is a great Gimp plugin and tutorial for HDR blenging. The basic principle is to take three pictures with different exposure values (dark, normal and bright) and mix them together. A good algorithm can do that pretty easily for you. A sample picture can be seen below. In the left upper corner, there is the dark exposure. In the upper right corner, there is the normal exposure, the bright exposure is placed at lower left, and, eventually, the result image is at lower right. Note that you can see the background, while there is the candle wick still visible below the light.

HDR Photo

Layer Effects

In Photoshop, layer effects are built-in. These effects can do some easy manipulation with the image and is one the most criticised lacks of Gimp. Fortunately, there is a plugin that can be easily installed and works pretty much the same way.

Layer Effects Demo

Shadows and Highlights

This plugin allows you to manipulate dark and light parts of the scene. It can automatically extract these parts into new layers and by using the layer opacity you can configure the light in shadows and darken the bright parts.

This is not such a miracle, but it is very useful in infrared (IR) photography.

IR Photography

The biggest issue with IR photography is that usual DSLR cameras have a fixed built-in IR filter before the image chip. This is to avoid unwanted light. But for IR photos we want it! The solution (except for camera disassembly or buying Sigma SD14 with removable filter) is to increase exposure period. It can take several minutes to get enough light with an IR filter on your lens.

Now, when we have a photo, how to process the red scene we obtained? There is a great Photoshop IR tutorial. But I wanted to do that in Gimp. There is a tutorial in a forum that resembles the Photoshop procedure. To summarize that:

  1. Realize what is in individual color channels - red is brightness, green is sharpness, blue is noise.
  2. In Gimp go to Colors, Levels and try Automatic or set a reference white point (which is something that produces most IR light - a green leaf on a sun for instance). You can also setup individual channels as you like.
  3. In Gimp select Colors, Components, Channel mixer and switch the red and the blue channels. This is done by setting 100% for blue and 0% for red with the red input channel and vice versa for the blue input channel.
  4. Now is the best time for the Shadows and Highlights plugin.
  5. Finally, you can try Colors, Hue/Saturation and add a little bit of Hue (+15 - +24) and possibly add some Saturation as well.
  6. Bonus step is to open Colors, Curves or Colors, Levels and fine tune the image colors.
IR Photo
. .