3D-Daz Daz3d Art - Show Us Your DazSkill

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m4dsk1llz

m4dsk1llz

Engaged Member
Feb 13, 2019
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Jumbi said:
That does not make much sense. Upon downscaling you are compressing the pixels, which should reduce the noise if anything. In fact, that's a well-known technique, from what I've gathered since I started to get interested in Daz.

As for uploading 4K images, go for it. As long as each one is below the 15 MB mark, you should be able to upload them directly to F95zone servers. I usually upload 4K renderings in here. I could understand your hesitation and your consideration towards others' bandwidth if you flooded the thread with your work, but that's not the case. And it's not only me who post 4K renders in here BTW.
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15mb is the key limiter for F95 uploads, besides if you are uploading 4K jpgs that meet that 15 mb limit you aren't really doing yourself any favors, since jpg compression is not lossless. When you set JPEG quality to 100, no real DCT quantization takes place but you are likely carrying out chrominance subsampling. With this behavior, information is lost, even when no quantization happens. JPEG encoding implies going to the DCT quantization domain, which causes rounding of coefficients. Rounding discards some information. This will happen regardless of all other options.

I know this is more technical than most people want to delve into, but we should all know as artists that when we save our images as jpegs, even at the highest quality, we still compress the information and that compression discards information that is lost forever. That is the very reason why you have photograhers like Jared Polin and others almost always use RAW formats so loses do not creep into their workflow.

Yes, there is a lossless jpeg compression but so little supports it, that it is almost never used.

Using png files is a whole other discussion.
 
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atheran

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Feb 3, 2020
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Jumbi said:
That does not make much sense. Upon downscaling you are compressing the pixels, which should reduce the noise if anything. In fact, that's a well-known technique, from what I've gathered since I started to get interested in Daz.

As for uploading 4K images, go for it. As long as each one is below the 15 MB mark, you should be able to upload them directly to F95zone servers. I usually upload 4K renderings in here. I could understand your hesitation and your consideration towards others' bandwidth if you flooded the thread with your work, but that's not the case. And it's not only me who post 4K renders in here BTW.
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It compresses the noise, not reduce it. You don't get any new information by downscaling. Plus the noise I put is there for a reason. I'ts a specific size to simulate a camera grain noise. Even if all information was kept by downscaling, there are not enough pixels around to get that effect properly. I do clean renders when possible and I put the noise in myself. What you said however, applies to noisy renders that people downscale in order for said noise to go away, or be minimized if possible.
 
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atheran

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Feb 3, 2020
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It was annoyingly quiet at work, so here we go. This time I was bored and went a little more hands on with the post processing. Besides my usual stuff, I added glow, freckles, etc. It's far outside my usual process or type of renders, did not try for something realistic this time, though that skin looks great imo. Also, I was wondering why the render was so slow, even when running on gpu. I figured out in Photoshop that I was rendering at 8k+ resolution, so...fuck me I guess? :D

Red Test-1.png

PS. I wanted to add some blood rivulets flowing down from the needle insertion points, but didn't find a good way to do so, without spending hours in photoshop.
 
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Jumbi

Jumbi

Well-Known Member
Feb 17, 2020
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m4dsk1llz said:
15mb is the key limiter for F95 uploads, besides if you are uploading 4K jpgs that meet that 15 mb limit you aren't really doing yourself any favors, since jpg compression is not lossless. When you set JPEG quality to 100, no real DCT quantization takes place but you are likely carrying out chrominance subsampling. With this behavior, information is lost, even when no quantization happens. JPEG encoding implies going to the DCT quantization domain, which causes rounding of coefficients. Rounding discards some information. This will happen regardless of all other options.

I know this is more technical than most people want to delve into, but we should all know as artists that when we save our images as jpegs, even at the highest quality, we still compress the information and that compression discards information that is lost forever. That is the very reason why you have photograhers like Jared Polin and others almost always use RAW formats so loses do not creep into their workflow.

Yes, there is a lossless jpeg compression but so little supports it, that it is almost never used.

Using png files is a whole other discussion.
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I must be honest here and admit that I am not very sure why you introduced all this technical information about the JPG format. I did not even mention that in my reply to atheran. But it's interesting information in any case.
 
m4dsk1llz

m4dsk1llz

Engaged Member
Feb 13, 2019
2,601
16,890
Jumbi said:
I must be honest here and admit that I am not very sure why you introduced all this technical information about the JPG format. I did not even mention that in my reply to atheran. But it's interesting information in any case.
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It kinda fit with where i believed atheran was going, when you introduce a filter to add grain, which he does on many of his images, compression and downscaling are the worst things you can do to the image. But the post was intended just to pass along a bit of information that maybe others might not have known about the jpeg format. Jpeg is also the easiest format to compress and everything supports it, so a lot of people upload the easiest format. Looking back at atheran's post it seems he always uploads PNG files, so it wasn't a answer he could use. PNG files do compress losslessly so the file you create is the file F95 can display, without any other manipulations.

PNG is almost universally better to upload to a message board than jpegs, and a lot of people don't know that. I always upload PNG files unless for some reason I can't (bad source, etc). But I also render in 8k then downsize to 2.5k (approx) so my images on F95 are never the same as what I created.
 
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5.00 star(s) 12 Votes