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Arguably the first thing that comes to mind when talking about post-processing and lighting effects

is glare. glare or blooming is the optical effect where light from bright source appears to leak

into surrounding objects. by default the Blender glare node takes the bright glints that go above

the threshold of 1 and adds these little streaks. by the way you can press M to mute

the note temporarily and M to bring it back. so the core of the effect is just to detect the brightest

pixels falling outside a certain threshold and then you can add the fog low to them for example.

to work in a physically plausible manner it totally depends on the scene referred

data, the type of data Blender uses by default for its calculations when we hit

the render button or otherwise to preserve the dynamic range as we have mentioned you

you have to use the open exr format or any other 32-bit unbounded scene referred format.

in addition to glare we can try to simulate different types of photographic blooming

effects, for example simulating diffusion filters, these type of filters or in some cases dabbing

Vaseline directly onto the lens is used to create a hazy, dreamy glow. we won't keep it

in our main setup, but let's have a look at this effect just for the sake of off topic. if you feel

like borrowing this effect from photography and cinematography for that matter, we can go

with the mix filter, god... what I'm saying... it's not filter, it's a mix node and then we add the blur

filter which expects our image as an input, so we should probably plug the glare output there...

so far we don't see anything spectacular and that is because we need to connect it

to the second socket of the mix node, then what I usually do is strike the relative

checkbox to make it non-dependent on the scene resolution and then up the X and Y blur values

to be fair... uh... to make it look uniform we should also play with the aspect correction,

I will check the Y aspect correction, as for the amount of blurriness I want it to be

fairly dreamy and hazy, but still retain some bigger shapes if that makes sense.

now to make it shine the mix factor should be switched over to add. the add mode is one of the

safest blending modes when working with the scene referred light data, add, multiply... what else? mix

pretty much everything else is broken when when working with the unbounded light values. all right

but now we have to compensate the exposure and we can do it of course with the help of the exposure

node or just by using good old RGB curves. trying to eyeball or rather approximate the brightness.

okay now it should be possible to compare before and after by muting these two nodes

and toggling them back on. all right, it is dreamy, it is hazy... it is 90s as hell :) probably

not my type of effect, not always at least and still it has its place in very small doses, uh...

to unify the light values ever so slightly across the image, something like that anyway.

so that is another filter from photography that we can try to simulate using compositor nodes.

but meanwhile let's get rid of our soft diffusion setup and take a step back.

so once upon the compositor there was a glare node. let's start from here.

now moving on to copying some other mistakes of photographic image formations such as chromatic

aberration within the lens and it's also known as color fringing and it produces the colorful

outlines around the edges of the objects, it can be an unwanted or highly desirable effect

depending on your style, but if we talk about CG lighting, it's fairly important to know how

to pepper your image up with such "mistakes". in Blender the easiest way to achieve chromatic

aberration is to use the lens distortion node and then crank up the dispersion value.

it just blew the picture up into this kind of colorful mess which proves that every

effect should be used in moderation :) and when we set the mode to projector it is much more

bearable, much more palatable. the amount of dispersion or chromatic aberration is

a matter of personal preference, but I like it in both CG and in photography for that matter.

there is something very attractive in the idea of the different wavelengths of light splitting

inside the lens to produce this effect. kind of reveals the inner working of light that passes

through the lens, which shows that the lens is very complex object indeed. there is a certain

how should I put it... an image formation depth about it and some people there say that it looks *good*.

following the theme of the optical aberrations that should degrade the image but actually make

it look better, here is another one, the vignette effect that is often associated with the retro

lenses. the vignette effect is all about darkening the edges of the image, as simple as that and we

can do it procedurally in Blender compositor. I'm going to go matte and add the ellipse mask.

The mask should go into the mix factor of our newly created mix node, there should be

this type of white ellipse right in the center of the screen, we need to scale its width and height

so it's approximately touching the edges like that. so the width of 1 and the height of 0.4 something

gets the job done. now it has to be inverted, so the mix node affects the edges of the image only and

obviously if we are aiming to get the darkening effect the color should be made darker. there...

as for the blending mode I have just said that everything aside multiply, add and

mix is a blunder and here I myself set the mix mode to soft light, but okay, fair enough :D

the blur node can be used to gradually soften the edges of the mask

and the intensity of the effect is basically controlled by altering the shade of gray...

can't stop thinking about the blending mode... we should change it... and true, multiply is way safer.

add, multiply and mix just doesn't screw the colors, these operations are perfectly linear,

perfectly safe for the scene referred linear type of data. all right cool, so that was the darkening

around the edges effect aka the retro vignetting effect, it's classic, it's timeless and elegant and

very easy to do. that is why it's always welcome to our cinematic post-processing effects party.