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View Full Version : Which image file format is better: psd or tiff?


Geoff Tani
18 September 2005, 10:53 PM
I am new to image formats, and I am looking for the image file format that retains the most data about the image. I assumed that either PSD or TIF did this. I further assumed that they were interchangable: that you could save a file to PSD, then convert it to TIF without any loss of data, and vice versa.

I discovered the following when I scan a letter sized document:

Doc scan at 600dpi greyscale saved to TIF = 33MB
Same scan at 600dpi greyscale saved to PSD = 10MB

Given the difference in file sizes, are my assumptions wrong? If I save to PSD, then convert the file to TIF later, will there be loss of data? Is there loss of data going the other way (TIF to PSD)?

Which is the better file format for images? PSD or TIF?

And if PSD and TIF are really the same high quality, how is it that PSD can be so compressed, compared to TIF?

Thanks for your help.

theKiwi
18 September 2005, 11:01 PM
PSD files are usually smaller than TIFF files because the PSD format has compression built into it to make the files smaller. This is lossless compression, and doesn't affect the contents of the file - you can open it, save it close it numerous times without affecting the quality of the image it contains.

TIFF files are not as compressed (if you choose LZW compression) or aren't compressed at all if you don't compress them, and so are much larger, but contain the same information about the image they contain.

If the files are only going to be used by you, save them as PSD files, but if you're going to exchange them with other family members, the TIFF format may be better as it can probably be opened by more different software than can the PSD files.

Roger

Geoff Tani
19 September 2005, 01:50 AM
Thank you very much for the information.

I already have many files saved to PSD. With distribution to other people in mind, if I open those files in Photoshop, and convert them to TIF, would I lose image information in the process? To put it another way, would an image saved to PSD and later converted to TIF have the same information as the same image saved to TIF originally?

theKiwi
19 September 2005, 07:22 AM
Yes.

Cheers

Roger

Geoff Tani
19 September 2005, 11:13 AM
Yes.


Thanks again.

I assume your "yes" reply was to the question:

"To put it another way, would an image saved to PSD and later converted to TIF have the same information as the same image saved to TIF originally?"

Anyway, I really appreciate your help.

Geoff

MHill
19 September 2005, 11:52 AM
For color and grayscale images with only one layer (e.g., scanned documents), I generally save as PNG, which is also lossless. I find that the file size is usually smaller than PSD.

theKiwi
19 September 2005, 12:49 PM
I assume your "yes" reply was to the question:

"To put it another way, would an image saved to PSD and later converted to TIF have the same information as the same image saved to TIF originally?"

Yes, my Yes answer was to the above question.

Roger

Venita Roylance
21 September 2005, 02:19 PM
I am new to image formats, and I am looking for the image file format that retains the most data about the image. I assumed that either PSD or TIF did this. I further assumed that they were interchangable: that you could save a file to PSD, then convert it to TIF without any loss of data, and vice versa.

I discovered the following when I scan a letter sized document:

Doc scan at 600dpi greyscale saved to TIF = 33MB
Same scan at 600dpi greyscale saved to PSD = 10MB

Given the difference in file sizes, are my assumptions wrong? If I save to PSD, then convert the file to TIF later, will there be loss of data? Is there loss of data going the other way (TIF to PSD)?

Which is the better file format for images? PSD or TIF?

And if PSD and TIF are really the same high quality, how is it that PSD can be so compressed, compared to TIF?

Thanks for your help.

TIF/TIFF will save every pixel of your photo with no compression at all and is therefore excellent for archive photos - such as scans of old family photos. It creates high memory files and can be opened by most photo software. PSD uses some compression and creates smaller files, but is not always easily opened by other photo software.

My suggestion is to save your most valuable photos as .tif/tiff files. You may wish to copy them to a flash drive, cd, .mac account, or etc., as a backup to your hard drive. You can save copies of them as .jpg files to share.

Other photos, such as snapshots to be shared with friends, etc., could be saved as .jpg files which compresses the information. JPG is a universal format which can be opened by most any photo software. Any photos that you wish to post on the internet or email to someone should be in the .jpg format to provide the most universal access.

Yours,

Venita