PNG vs. TIFF

[z-vet]

Hi all
I need an opinion on PNG format compared to TIFF.
For now i store my converted RAWs in 16-bit TIFF format, which results in 55 Mb files. Saving them in PNG gives me 30-something Mb, and PNG can store EXIF as well. So i think to switch to PNG completely. How good PNG is compared to TIFF? Should i switch and use it or it's better to stay with TIFF? Any other things i need to know?
Thank you.

[jdepould]

Why? Just keep the raw files.

[z-vet]

I do keep the RAWs, but i convert them for processing and store them in TIFF. Then i do all the cropping-levels-whatever and store the resulting image in original size uncompressed so i can print it, and a smaller JPG for Web.

[oldwolf]

doesn't png handle only 256 colors? it supports transparencies but i thought it was only 256 colors. maybe i'm thinking of a different file format?

we convert everything to tiff to process. if we're using a lot of layers and we want to remmeber how we did something then we save it in the native psp (psd) format with all layers turned invisible to save room and make the file size not so big. if we do that then we just delete the tiff file.

yes, we convert to jpg but only to upload to the client's private gallery or to send to the photo labs.

[sk66]

A lot will depend upon your work flow and "product".
I do most of my editing in Lightroom which basically means I do "no editing" to the original file so I just keep the RAW and lightroom files...
If I edit in Photoshop, then I save the Tiff. IME most print clients prefer to get Tiff's, but maybe that's changing...
If I need a Jpeg/Png, then I convert at upload....I don't usually keep those files on my backups....they can always be recreated.

As for file size concerns...I keep everything on external drives and they are getting cheaper every day.

[dcclark]

True... if you're going to bother to keep not only raw but also converted, lossless files (that's really a lot!), you may as well not worry about file size. Anything you do will be huge. Since, as you point out, PNG can handle EXIF, you may as well go with it. PNG is an open standard, which means that it is likely to be accessible for a very long time to come.

[oldwolf]

I guess I'm off my rocker. It seems if you use transparencies in PNG then it converts to 256 colors. Not sure if that's just in the program I use or if it's true in PS as well.

I try to set a color to be transparent and not by using masks and stuff and it converts my pictures to 256 color but if I just keep it as is and don't pick a color to be transparent then all is good.

[dcclark]

Originally Posted by oldwolf

I guess I'm off my rocker. It seems if you use transparencies in PNG then it converts to 256 colors. Not sure if that's just in the program I use or if it's true in PS as well.

I try to set a color to be transparent and not by using masks and stuff and it converts my pictures to 256 color but if I just keep it as is and don't pick a color to be transparent then all is good.

You may be going about it wrong. PNG format supports an entire alpha channel -- perhaps the program you're using assumes that you want to be in 256 color mode if you choose a single color to be transparent, but you may be able to add a transparency channel in a different way.

[oldwolf]

Originally Posted by dcclark

You may be going about it wrong. PNG format supports an entire alpha channel -- perhaps the program you're using assumes that you want to be in 256 color mode if you choose a single color to be transparent, but you may be able to add a transparency channel in a different way.

Yep, I was trying to go about it the easy way instead of using masks hehe.

That's why I had to go back and check.

[OsmosisStudios]

I only ever use TIFFs for printing, and they're processed from the RAW file. I use jpgs for everything else (jpg holds EXIF too)