Geograph - photograph every grid square

[the beginnings of an answer]

Put simply, photographs are made of light. In good light, today's digital cameras make it difficult to take a technically poor photo. Sometimes, though, photos unavoidably come out dark or grey because the subject was in shadow, or it was getting late; worst of all, a cloud appeared overhead and followed you round while the distant landscape was bathed in sunshine. There are ways of making these photos reveal their subjects better.

This isn't a highly technical answer. It refers to features of commonly-used image editing or image enhancement software.

[to be continued]

Geograph is primarily for documentary photographs, not works of art. If your photos clearly show the subject, are well-lit, straightened-up, in focus and if possible visually appealing, you're doing fine. In the Collections area of the site there are many examples: see any of the 'Stellar examples' in Themed topics and illustrations of Geographical context at http://www.geograph.org.uk/tags/primary.php

Light
Generally speaking, sunshine gives best results, but time of day and time of year impart their own qualities to a photo. In bright summer light in the middle of the day, subjects are unavoidably top-lit, often reflective, while shadows are short, intense and below the subject. In the early morning and from late afternoon the sun is lower in the sky, subjects may be side-lit, the light is less harsh and shadows may be attractively long, revealing the form of objects they lie across. Similar conditions prevail in the middle of the day in the winter months. Photographing into the light is not recommended. 'Contre-jour' effects are expressive but may not convey much geographical information. Sometimes, however, you should ignore advice such as this and just respond to the subject and the conditions. For very bright surroundings such as snow, beaches and expanses of rock or concrete, consult your user guide.

Shadow
Subjects and scenes in shadow may sometimes have to be photographed "ready or not". The sun goes in or clouds merge. Pointing the camera more towards the ground will make auto-exposure adjust for a darker subject. If you prefer more control you can change the camera settings: look in your user guide for topics such as 'ISO speed', 'Metering mode' and 'Exposure compensation'. There may be less control with a camera phone: photos taken in poor light are likely to be dark or dull. To salvage something from a disappointing photo, see the answer to the question 'How can I improve a photo?' On the other hand dull days provide opportunities for photographing other subjects, such as details. Exploit the 'flat' light with zoom shots of distant subjects.

Night photography
Photographs taken at night are often classified as supplementals. That is fine; they can reveal geographic and cultural realities not evident during the day. There may be multiple light sources. Again, consult your camera's user guide. Experiment — and stay safe.

edited by Robin Stott

Actually I like Photoshop. It IS expensive, but you can purchase cheaper versions of it which are perfectly capable. It does take a little time to learn, but if you can master the keyboard shortcuts it helps a lot. It really can do everything - from HDR to 3d painting.
There are loads of Image editing applications, including the free one GIMP. Its personal preference. GIMP is very capable, but I'm not personally keen on the interface, even if it is a bit like Photoshop. It also runs on Linux.
In windows, its useful to have the application set up so that a right click on the image will launch the application, or open the image in it.