Changing Brightness and Contrast Without Affecting Saturation

A Color Experiment

A while back I was made aware of an article on DPReview.com entitled Reducing Contrast Without the ColoursFading (using GIMP) wherein Tom Axford talks about the need for reducing the contrast in or otherwise brightening an image to make it look better in print. His original technique involved using an HSV model to make adjustments to a value layer without affecting the saturation of the colors in an image.

Intrigued by the concept, I decided to perform an experiment to see exactly what effect brightness and contrast adjustments have on colors. I created three squares, one each of red, green, and blue — red being lighter, green being darker, and blue being of medium intensity.

How to Replace the Sky in a Photo

A Simple GIMP 2.8 Tutorial

Have you ever had a nice outdoor picture of something, say a building, where the exposure on the building was good, but the sky looked drab, washed out, or overexposed, and you wondered what you could do to make the sky look better? You could replace the sky either with a simple solid blue color of the appropriate intensity or with a linear or radial blue gradient. Sometimes that's fine, but sometimes you'd like a different effect to make the image more interesting.

In this tutorial I'll describe a technique you can use to create this image:

from this image:

One Method for Adjusting an Underexposed Photo

A GIMP 2.8 Quick Tutorial

I was perusing my zebra photos one day and came across one showing a zebra running away from me at full tilt. The photo was really underexposed, but I liked the dynamics of the image, so I loaded it into GIMP and started playing around with it.

What follows is a description of how I created this image:

from this image: