Little experiment: (non destructive) Jpeg compression effect using filter layers

[ENJERUNE]

Hello! ive been experimenting with filter layers recently, so i thought i would share some of that for anyoneinteresed

yesterday i felt inspired by Jam2go’s video about jpeg compression where he applies this visual effect (and some others) in the depth of field in his game.
video here
I wanted to try something similar in krita.

I know that the G-mic-qt plug in has a jpeg artifact filter and for the effect itself it is really good!!, however the G-mic-qt filters are destructive so if i wanted a bit more artistic control over the effect i would need to do something else.

A simple solution would be to use a pixelize filter and a posterize filter.
before

after

this is…fine. but some of it is lacking, instead of jpeg compression it feels more like pixel art, wich is not really what im going for even though i think this is a cool effect too

Making some research, something that really contributes to the jpeg artifacts is this thing called “discrete cosine transform”, im gonna be honest, i dont fully understand the technical aspect of how it works, but from the little bunch i understand is an algorithim that uses a combination of patterns to recreate as closely as possible the uncompressed image

something i did to fake this effect was to make 3 pixelize filters with diferent values

one where the height was wider and shorter (25 x4)

one where the effect is a little smaller but with more height than width (2 x 15)

and one with very little diference to the original (6 x 4)

then i adjust the opacity of the pixelize filter layers, the one with the strongest effect has less opacity, the one with the least effect has more. it will depend on how strong you want the artifacts

the i add a posterize layer

something i consider extra but Jam2Go applies this in his video and i quite like the effect, (this is not really part of the actual jpeg compression from what i know) you can add a sharpen filter (or mean removal if you want something stronger) to make things more crispy, if you dont want the effect to be too strong while still being noticable you can put the layer in parallel mode or you can just lower the opacity (or both).

Now, i know that this effect is not aesthetically pleasing for everyone, but for me you can flex something and fool your friends with it…I mean, have you ever seen a JPEG image with TRANSPARENCY?

either way. If anyone has any ideas on how could this be improved please let me know :>

[nehakakar]

Interesting technique! For non-destructive compression effects, tools like JPEG Compressor could also be helpful to test JPEG artifacting and quality without altering the original image. Great for experimenting with subtle artifact effects

[ENJERUNE]

@ENJERUNE

mind if i ask, what is JPEG Compressor? is it some software in specific? looking it up only gives me a bunch of online jpeg compressors (which do pretty much the same thing as the G-mic filter or saving a file with low quality in krita)
What im trying to achieve with this is not only the effect of jpeg compression artifacts but also have some control on every part of the compression for artistic reasons, like only applying an amount of these artifacts in a specific area of an illustration

mind if i ask, what is JPEG Compressor? is it some software in specific? looking it up only gives me a bunch of online jpeg compressors (which do pretty much the same thing as the G-mic filter or saving a file with low quality in krita)
What im trying to achieve with this is not only the effect of jpeg compression artifacts but also have some control on every part of the compression for artistic reasons, like only applying an amount of these artifacts in a specific area of an illustration

[nehakakar]

Hi ENJERUNE
JPEG Compressor is a tool that compresses JPEG images while keeping their quality. Here is the website- jpegcompressor.com. It’s great for preserving detail. If you need more control for artistic effects, you might try software like Photoshop or GIMP. They let you adjust compression settings and apply effects to specific parts of your illustration.

[ENJERUNE]

hmm ok, well this is not exactly what im looking for, the website just seems to be a compressor site, almost lossless compressor is possible when you save in krita as a jpeg file. Same could be done in GIMP and Photoshop.
GIMP and Krita share this plugin called GMic that allow to apply a JPEG artifact filter
These options are good as i mentioned in my OP, but i was doing here was not just recreate the compression itself, i was just trying to take that process, fake it using other filters just for artistic non destructive effect as inspired by Jam2Go’s video where he tries to mimic this effect for real time rendering in his videogame.
Using any Jpeg compressor website, saving a krita file as a jpeg, using photoshop and gimp, and using the GMic filter are all good ways to achieve the effect but are destructive and lack control other than the overall amount of compression