What do Lightroom Presets do?
In short, Lightroom presets take your adjustments that you used on a previous photo (like exposure slider, white balance, etc), and applies those settings to a different photo in one click. When you are happy with your adjustments on one photo, you can save those settings as a preset to use later on.
Editing in Lightroom
With Lightroom, you can change different settings such as exposure, white balance, clarity, etc. You can edit a photo to your liking by changing the various sliders in the Lightroom Develop module. For example, take this photo for instance:
Say we wanted to change the settings to increase the exposure, contrast, etc.
It may take a few minutes of tinkering to get the look I want, but I ended up turning this Raw image into a better looking image. After I am happy with it, I can save some, or all of these settings into a preset.
Lightroom presets are essentially settings that you can save and re-apply to other photos in one click. They are very convenient and easy to use on other photos in one click.
Presets are saved settings
Many photographers will find that they continually apply similar settings to various images. To save time, they create presets for different types of edits.
You can choose to save just some presets or you can layer your presets in a way that allows you to stack settings to photos. For example, you could either add the exposure, contrast, vignetting, etc all in one preset, or you can separate those settings to be different presets.
It just depends on the way you want to work. Some prefer to have all their settings saved in one preset, others like to have them saved in different presets.
Presets are like iOS or Instagram filters
Another way people use presets are as filters. You can really add some oomph to your photos and enhance the creative process with Lightroom presets.
Many other photographers like to purchase full blown preset systems and packs to give them a large library of various presets to choose from. These photographers like to apply different presets to their photos, to achieve different looks to their photos.
Its nice to be able to have many different presets to choose from, to turn your images into a different style or give it a different look. For example there are split tone presets, vintage presets, HDR presets, Black and white presets, etc
You can create your own library of different presets that offer a wide range of different styles and looks that you can apply to your photos. However, many photographers choose to purchase preset bundles, since it can be very time consuming and challenging to create a full usable preset system.
A great preset pack can really speed up your post production workflow and enhance the creative process. You can use the presets as they are after clicking on preset for a photo, or you can choose to further customize those edits.
It is actually recommended to use presets as somewhat of a starting point, as no 1 preset will look good on every photo. It takes some cycling through presets until you find one that really shines. Then you can take that further and edit to your exact liking.