the png debate

[Nickh]

Hi,

We've been having a bit of an on going debate in the office about the best (quality v file size) image formats to be saving renders in, as we want to set a standard format that we all save in.

For animations we always use pngs, as they are small, uncompressed (as far as I know??) and store alpha channels - so work well with combustion. But some people think the quality of pngs is only good enough for these low res renders and not for high res stills. They are insiting on using tiffs for the main renders, but happy to use pngs for channel renders.

Do other people use pngs for high res stills?

Thanks
Nick

[vlado]

PNG files use lossless compression, so any argument about "quality" is pointless. They give you the exact same image as an uncompressed image format.

Best regards,
Vlado

[joconnell]

The only thing I don't like about them is that they read and write quite slowly in after effects - as vlado mentioned you won't lose any quality by using them and they'll probably compress a lot better than something like tga.

[Nickh]

Thanks Vlado and John. That is what I thought\hoped.

Luckly I've not noticed any performance issues in combustion.

Does anyone know of any reason why pngs shouldn't be used arcoss the board for all renders for any other reason?

I have had a few problems with backburner on a couple of jobs rendering funny pngs occasionally - the odd one renders out randomly at 48bit and combustion crashes when it tries to play\render them.

Nick

[Da_elf]

in some cases i prefer to use straight for my alpha channel and tga gives me the option to choose between straight and premultiplied.

[percydaman]

we use tifs here for some reason, not sure why. Well we've just switched to exr, so i guess we dont use tiffs anymore lol

[trixian]

on a side note, percy, are you by any chance called percydaman in eve as well? Think I met you a couple of years ago up in solitude?

[mike_kennedy]

WE use PNG for sequences and Tiff for stills because PS CS and all prior versions suck when dealing with PNG's, AE works well with them, not sure why Adobe can't get their act together on PNG files....We have pretty fast machines here so the speed is fine and actaully better becuase we work at HD and PNG's move across the network way faster than TGA or Tiff files...
Cheers
Mike K

[Nickh]

yeah there's no alpha choice is one thing.

Mike, how do they suck in PS? I've not notced anything myself.

[Morbid Angel]

The only thing I don't like about them is that they read and write quite slowly in after effects - as vlado mentioned you won't lose any quality by using them and they'll probably compress a lot better than something like tga.

this is understandable; since they are lossless and compressed, this is what has to happen on write, or read, I would imaging. Like opening an archive every frame.

From many places, I've used anything from tga, tiff, to exr, png...

I think for most cases if not dealing with film, png is a great way to go.
Or, in film pipeline, exrs are great for all the color info and then pngs for mats, alphas etc. Since if you render this color info into exr it will take farely large space on disk.

[sv]

I think for most cases if not dealing with film, png is a great way to go.
Or, in film pipeline, exrs are great for all the color info and then pngs for mats, alphas etc. Since if you render this color info into exr it will take farely large space on disk.

yes, i completely agree, and this is more or less the way i work.
also PNG's are really good for compatibility - the way they handle transparency is used great by other, non-compositing programs like flash etc.

[andrewjohn81]

I pretty much agree with everything there.

As a general rule here we use png for any animation.

I use png when we don't have any alpha using shadows. But for print stuff I'll use tiff or targa. Tiff seems to be the general favorite around here.

Open up a png that has a soft shadow fading on the ground. You'll notice it looks fine in a tiff, but the shadow probably won't even show up in the png at all. This is due to the premultiplication stuff. #1 reason we don't use png's for stills. I've done it on accident before and had to end up opening it up in after effects first, then saving it for psd, Then finally editing it in photoshop. I wish PS would give you the option.

Hope my input helps your decision.

[percydaman]

on a side note, percy, are you by any chance called percydaman in eve as well? Think I met you a couple of years ago up in solitude?

interesting you should say that. I have a very old account that I think was named percydaman from like 2003, that I thought I cancelled (might have given account to corp at time, not sure) Ive had to create new chars: TheReverend and Fuhshizzle.

But as you say, I've been trying like mad to find those old accounts, and couldn't remember their login or email. Funny if someones been playing my original account after all these years.

I hate starting over

[cpnichols]

I use pretty much exr because we work in linear space and want some good float data.

[panthon]

I use RPF all the time, because I use DOF, MB and ID selection from combustion for all kind of obscure purposes. Unfortunately, this format slows down combustion A LOT, but the flexibility is unbeatable.
If combustion had support for EXR channels, I would switch to EXR.