What are Filter Layers and why should I use them?
Let’s say you want to turn a photograph black and white and apply some tone adjustments. You turn the photo black and white, fix the contrast and you are happy with it so you save it. Then you think actually maybe I overdid the contrast and actually I liked the colour version. If you saved over the original then I’m afraid there is no going back.
This is what is known as destructive editing. Each change you make alters the original file and can only be undone by pressing Undo (if you haven’t saved over it).
This is the bad way of editing files.
Non Destructive Editing
Non Destructive Editing is the opposite of this approach. With this method, every single change can be toggled, changed or removed at any time. If you work professionally this is the only way to organise your work.
Rather than edit the original image this approach stacks the alterations on top of the image but leaves the original image unchanged. This is where Filter Layers come in.
If you are already familiar with Photoshop this is the same thing as Adjustment Layers.
So allow me to demonstrate a non-destructive way of editing a photograph in Krita.
I open up my original image in Krita.
Now rather than select the filters from the top menu, I am going to create a new filter layer.
So first I am going to add a desaturate filter.
This has created a new layer which sits above the original image. Although the end result is a desaturated image the original image is unaffected and I can toggle the effect on/off.
So next I am going to tweak the levels a bit so once again I create a new filter layer and select the levels adjustment filter. Once again a new filter layer has been created leaving the original intact. I select Auto Levels.
Applying the same steps I used on the two previous filters, I finally add a sharpen filter to finish the image off.
The reason this is the best way to work is because every filter can be removed or toggled on and off. I can even change the settings of the filters by right-clicking on the filter layer and then selecting properties. This brings up the Filter options, I can now change the original settings I selected when I created the Filter Layer.
You can also adjust the opacity of the Filter layer which gives you the option of easing in the effect. You can re-order the layers too, this will also affect the end result.
Adding Masks to Filters
Let’s say you only want to adjust one area of the photo. For example, it’s incredibly common for the sky to be overexposed in a photograph. So in order to fix this issue, you would want to darken the sky but leave the land unaffected because the land is already correctly exposed.
This is where you introduce a transparency mask to the filter layer. The transparency mask allows you to select which area of the image is affected and by how much. Allow me to demonstrate.
In this photo, the sky is too bright (to be honest the whole photo is a bit too bright). So I add a filter layer with a levels adjustment and tweak the settings until I like the way the sky looks. I ignore the ground because I know I will mask it out.
With my levels filter applied I next create a new Transparency Mask. This mask will determine the coverage of the levels adjustment. What I am going to do is create a gradient over the sky of the photo. This will ease in the effect over the sky so it doesn’t look too harsh.
To do this I select the new mask layer and draw a gradient with the gradient tool. The gradient goes from black to white. Black being transparent and white being opaque.
If you want to isolate the mask layer so you can work on it without distractions, right click on it and toggle isolate layer.
Finally, pick the blend mode which suits your photo best, normal is what I picked.
As you can see above the sky has been gradually darkened but the rest of the photo has been left alone.
Finally, make sure you save your file as a Krita Document so you can edit it in the future. As long as you keep your Krita Document, you can export multiple variations of the same image forever.
Another reason it is a good idea to work non-destructively with photos like this is due to the variance of computer screens. You could work on one monitor which is too bright (often laptops) and end up darkening the photo more than needed. Then when you go on to another computer with a better screen set up you realize your photo is too dark.
This happens a lot when people print their photos, the prints come out too dark because the photo was adjusted with a screen that was too bright.
Thanks for reading.