Pages: [1]   Go Down

Author Topic: Tiff format  (Read 7368 times)

mbalensiefer

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 297
Tiff format
« on: February 21, 2011, 05:29:01 am »

When saving as Tiff, should I save as 32 bit (Float), 24 bit (FP24), or 16 bit (half)?
 I will eventually output to .jpg.

Also, Tiff save options in Photoshop give me an option for "pixel order":
 Interleaved (RGBRGB)
 Per Channel (RRGGBB)
--> Which one is optimal, and why?.
 

I get the Photoshop options to Save Image Pyramid (default position is "Off").
--> Do I ever save in Image Pyramid?

Also, under Image > Mode > I can change my mode to:
8bits/channel
16bits/channel
32bits/channel
--> How does this differ from Tiff Saveas options?

Thank you
Michael
Logged

langier

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1502
    • Celebrating Rural America, the Balkans and beyond
Re: Tiff format
« Reply #1 on: February 21, 2011, 09:56:28 am »

Here's a few basic settings for saving TIFF files, YRMV.

If you are working with a raw file and work in 16-bit color, simply save as a TIFF file, no compression, interleaved, and I don't think that the Byte Order (IBM vs. Mac) matters much today since with main-stream programs, each respects the other with this legacy setting.

Always save your master file, including layers, so you can revisit it as needed and so you don't have to repeat the time and effort needed to recraft your image! You can always dumb down your master file into an infinite variety of purposes, but a dumbed-down file, say you settled on 1000x1500 pixel jpeg file, can't be reworked back to your original quality.

Now if you normally shoot jpeg files and convert to TIFF, it's already an 8-bit file and you can save it pretty much with the above settings, with the exception it doesn't make sense to up the bit depth to 16 since it only creates a larger file with no increase of quality.

You can save some file size by using Lossless compression of LZW but with the size of today's hard drives, it's almost a moot point to compress your files. LZW does save 10-40% space on an 8-bit image, but sometimes makes 16-bit images larger. It will take more time to both compress and decompress the image and it may not be compatible with fringe software. In 20-plus years of working with TIFF files, I haven't found any problems in working with the compressed TIFF files other than when a client bought some funky program in a bargain bin that said it supported TIFF and later found it was some ancient flavor from TIFF's early years...

Pretty much the dialog box has giving you TMI and you need to simplify to the mainstream settings. IMO, the defaults as set in PS are usually quite adequate and you don't need to worry too much in the mainstream about them. It's one of those things that we tend to set once and forget and get back to crafting our images.
Logged
Larry Angier
ASMP, ACT, & many more! @sacred_icons
https://angier-fox.photoshelter.com

mbalensiefer

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 297
Re: Tiff format
« Reply #2 on: February 21, 2011, 10:09:05 am »

Thank you for the reply!
 I wonder why Tiff does not have an 8-bit option under its File>Save As settings?
Bits listed are per-channel (RGB), correct?

As noted, Tiff's save options give you a choice of 32 bit, 24 bit, or 16 bit...

But, under Image > Mode > I can change my mode to:
 8bits/channel
 16bits/channel
 32bits/channel
--> How does this differ from Tiff Saveas options?

Michael
Logged

langier

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1502
    • Celebrating Rural America, the Balkans and beyond
Re: Tiff format
« Reply #3 on: February 21, 2011, 05:26:48 pm »

PS assumes that if you are saving a 16-bit image, you want the file to be 16-bit. If you are saving an 8-bit image, you'll get the menu for that.

Having a check-box in 16-bit to save as an 8-bit file would lead to a lot of grumbling for many if they checked the box by mistake and then realized a few or even dozens of images later that their master 16-bit files were now dumbed-down to 8-bit.

It wasn't until PS-CS-5 that we could take a 16-bit tiff/psd file and "save-as" a jpeg without first dropping down the 16-bits to 8-bits before saving.
Logged
Larry Angier
ASMP, ACT, & many more! @sacred_icons
https://angier-fox.photoshelter.com
Pages: [1]   Go Up