I can’t remember how many times I have accidently saved a Blender render as .png just to realize that it isn’t enough for post-processing. Wasting hours re-rendering because I didn’t save the result correctly.
You can render images and animations from the “Render” menu. When the rendering is done, go to “Image->Save” in the image editor for still images. Animations are automatically saved in the default output folder. On windows this is “c:\temp”.
That is the basics of saving our render result, but there is more to the story, read on to learn how we can get the most possible data moved from our final render to disk. Enabling us to post-process later or in another application.
To save the most possible data into your finished image render follow these steps:
So, why can’t I just hit save, give my image a name and be done with it? Well, you could but you might lose valuable information hidden in your render.
To understand the amount of data that is output by Blender when we render, we need to investigate render passes. We will use the render engine Cycles for our example.
You can read a full guide on render passes in the article below. In this article we cover the basics.
Related content: Render passes in Blender Cycles: Complete guide
When we render an image, we collect certain information that combined will give us the final color of each pixel in the image. In cycles we can pick out these individual contributors and separate them. Each separation is called a pass. Here are some examples of render passes that we may want to use.
This is not a complete list, there are many more and you could find them if you got to the “view layer” properties in the Properties panel and find the “Passes” section.
The point that needs to get across is that we can use all this extra data in our post-processing to enhance our renders. Just like a photographer would use a RAW file format to access all the data captured when the photo was taken, a 3D artist uses these captured passes of data for maximum flexibility after the render has completed.
Only difference is that as 3D artists we have even more control and data to work with if we want.
However, if we save our images in the default output format, PNG. We lose a lot of this information.
To maintain as much of this information as possible, we must select the passes that we want before we render. We also need to save our output in a file format that support all these passes.
The most versatile format available to us is OpenEXR. One could say that OpenEXR is the raw file format of render output in Blender. Just like the photographer using a raw file format when shooting images.
There are two variations of this format. The standard OpenEXR and “OpenEXR multilayer”. Choosing multilayer will save each renderpass as a separate layer. We can then open this file in any 2D art software we want and in most software the layers will be picked up by the software's internal layer system.
This works in Photoshop, Affinity photo and GIMP among others.
We can use any tool in the 2D application of choice to manipulate any of the layer and use Blend modes to combine them in different ways to get different effects.
OpenExr has another major benefit as well. It can store pixels brighter than white. This means that if some part of our image is blown out and only has white pixels, we can adjust this and bring details back.
There are also other file formats available to us that we can use with other benefits. PNG and JPEG are generally the file formats we use for web. Jpeg is often considered the final output format. For example, a jpeg is what we would send for printing.
Depending on the context, the file browser may look slightly different. It will adapt to whatever situation it is opened in. If we open this as part of a save operation, we will have access to save properties such as file formats and formats specific settings.
But if we append data from another blend file or export a 3D object the settings available will be according to the context it is opened in.
The context specific settings are found in the properties panel, toggled with “n”. We can also click the cogwheel in the top right corner to show these settings if they happened to be hidden.
On the left side we have some shortcuts for quick navigation around the filesystem. Volumes at the top followed by some system locations such as Documents and Desktop and possibly other entries for Mac and Linux users.
Next there are favorites. To add a favourite, brwose for the location in the main window and press the “plus” icon to add it to favorites. We can then use the arrow buttons to rearrange the positioning.
At the bottom are the recently used folders.
Above the main window we have some navigation buttons, create folder and the current path. We can aslo search for files and folders.
Then there are two drop down menus. One for filtering what filetypes are shown and one for sorting and displaying the contents.
At the bottom there is a box to fill the filename and on the right side there are plus and minus buttons that will increase or decrease the last number in the filename. This is convenient if you are saving multiple versions of the same file. Just press the plus and save to increase the number.
Apart from OpenEXR, Jpeg and PNG we have a few other file formats that we can use as well. The most important things are that you know that the file format is supported for the intended use. If you don’t know, save as OpenEXR multiplayer. Then you can always use that file to export to another file format later.
Let’s step back from the file browser for a while and look at what useful features we have in the image editor when our render is done.
By default, the image editor, formerly UV/Image Editor pops-up show us the progression of our render.
Once it is done, a few options are available. First, we can verify data about our image. Right click and hold on the image to get information about the pixel you are currently hovering over. We can check that the color values are sensible as well as the Z-depth if we plan to use this value in compositing.
If we find that we have light areas with color values above 1.0. Then this means that there is potentially more detail in that area that we might want to expose in post-processing.
We can also use the scopes. Press “n” to bring up the properties and find the “scopes” tab. Here we can see what color ranges we have in the image and get an idea if we are clamping values. The histogram shows how many pixels have a value close to 1.0(white) or close to 0.0(black) and any number in between.
In the top right corner, there is a small icon opening a dropdown if we click it. Here we can select what render pass to view.
Let’s now turn our focus to slots. In the top right corner, you can see that we are currently in slot one. We can change this to any slot from 1 to 8. If we change to slot two and render again, we can have two render results.
This feature simply enables us to have multiple renders in memory without having to save each render to a file. They are instead kept in RAM.
We can add more slots and change the name of these slots if we find the image tab in the right-side properties panel.
Find the “Render slots” subsection. Click the plus to add a slot and double click a slot to rename it. The “X” button will clear the current render slot.
In the “image” tab there is also a “metadata” section where we can find some basic information about our image.
In this article we covered some of the tools that we encounter as we save render images. The file browser allow us to navigate the file system and save files in different file formats.
The image editor allows us to view our renders, compare them and see what data we save and export.
Saving in the correct file format is crucial to not lose data once we close Blender.
Thanks for your time.
