Post processing

What does post processing means ? Macro Everything you do with the file after you took the picture.
As I think about it post processing of the photos is essential. On the other hand I prefer not to spend long hours in front of the computer, if not necessary, so I try to minimize post processing. As a general idea, if you like the picture as it is, try to do as minimal post-processing as you can, in order to avoid the over-processed unnatural look.

Software used for post processing

There are many software out there for post processing. The most popular is Photoshop and Lightroom. Capture one and DXO are other popular programs. Some programs do the whole process automatically using different templates, others needed to command step by step.
I think it is good to start at least a free Gimp level software, which can use layers, layer masks, curves, has sharpening options.

First what is needed before post processing ?

It is very important that we can make a correctly exposed, sharp photo. It is very hard to do anything with a blurred photo, or a badly exposed too dark or too bright picture.

Batch processing of images

There are many programs for batch processing of images. This can save many time for us. I usually use Linux most of the times, for Linux the Digikam or Gthumb is such program, which can batch process images. But even before it is very good to delete all images we don’t think is good, or we need it, this saves even more time. I prefer to delete them even in the camera if I don’t like them. I usually spend many times with searching particular images. The most used batch function is resizing for me. For most times I don’t need 3000 or more pixel size images.

Crop images

Cropping images are possible with many software today. The aim here is to cut out unwanted parts of the image, or magnify some detail in the image. In general it is a good idea to try to capture the image as we like and not crop afterwards, because cropping is time consuming. I always keep the original if the image is nice, it can always happen that it is needed.

One usual mistake is over cropping images, especially wildlife / bird photos. We usually cannot fill the frame, which would very good to put more pixels on the subject, resulting more detailed images.

Resize / scale images

I resize all images I took except the best ones. Usually most images doesn’t look good at 100% magnification. I usually prefer the batch resize functions which saves time.

Sharpness

There are essentially four method of sharpening:
1. Sharpening
2. Unsharp mask
3. Add contrast
4. Adjust light levels (curves).

There are some things here, which perhaps you cannot expects here. I start with adjust levels. If we are just started photography, many cases the problem with picture sharpness is just that the pictures are too bright, showing little contrast.

To cure this is very simple, there is a tool called curves, in Photoshop, Lightroom, or the free Gimp. The curves shows the curve which representing the photo. The left side shows the dark pixels, the right side is the white pixels. If we want the picture to be darker, we can grab a middle point on the curve with the mouse and move downwards. This makes the image immediately darker. It needs some care not to modify too much, which can result a too dark or weird image. We can move the curve up and down to evaluate which setting we like the most.

Contrast – Weak lenses can produce low contrast level. We can help about it in post processing in some extent. Usually we use a slider to do this. Here also need smaller adjustment to get the desired effect. If we are not sure what we do is good or not, to keep the original is a good idea.

At the end left the two “real” sharpening methods: sharpening and unsharp mask. What I forget is in camera sharpening. If we use Dslr camera according to my preference some sharpening is needed in the camera in order to avoid lots of times afterwards. I had two cameras, a Canon 30D and the Nikon D7000, in the Canon I give +2 sharpening and +1 contrast, in Nikon I give 6 for sharpening. According to our taste we can choose how we like our images.

I don’t sharpen all my images after taking them, just some of it, if needed. For example if I had a very nice photo sometimes I like it to be even better.

The simple sharpening sharpen the picture but doesn’t change contrast level. This is comes at the cost of some noise level improvement.

The unsharp mask function can give some contrast extra as well. For low quality images perhaps this is a more effective method. Usually there are several parameters here. I suggest not use the original ones, but experiment with it what you can achieve during the process. I don’t use always the same numbers here, different reasons use different parameters.

Contrast

Adding contrast can help a lot for an otherwise flat image. It is easy and quickly can be done. Adding too much contrast also can be interesting in artistic reasons, but most cases I avoid to give too much contrast.

Saturation

If we don’t like the colors of our image, we can add a little saturation in it, or even we can change the hue as well. Experimenting is a key word here as well, to get the best results.

Post processing just parts of the images

Many program allows us make post processing just some parts of the image. For example we want to get rid of some dust spots, wants the background to be more blurred, remove noise from the image.

Layers

Layers is a key concept for many post processing programs. We can duplicate layers, desaturate layers, copy layers, we can blend two image together. In Gimp I use open as layers function a lot. In that case we open an images and we can separately work on different parts of the image.

Layer masks

Layer masks are very useful for many purposes. For example we want a HDR image from different exposures (lighter and darker images of the same scene). We can put each image on a separate layer.

I also use layer mask if I don’t like the background, the sky for example.