TIF images lose sharpness

Anna from Michigan, United States, using Photoshop CS with Mac OSX, writes in with:

[Quote:]
I have been working for two days on some images. Some of them I have been working on in Tiff and some in Photoshop format. I have sharpened, color corrected and edited them. Then, when I go back to them and look at them in the browser they look perfect and then I open them and they have lost a whole lot of sharpness!!!

What has happened to them?

Everyone has always recommended to me to work in tiff and Photoshop formats instead of jpeg but I seem to be losing a lot of information- and this has not been over a long period of time- only hours! What can I do, these need to look good for my client. I have never had this problem before.
[End Quote]

If you can provide a good answer to this question, then comment below. Thanks for your help!

Comments

[James Thompson]

I know this is a very old thread but it does show up on Google when searching for info about tiffs so I thought I would chime in.

Daitenshi, you reccommend saving tiffs without any compression to preserve image quality, you do realise that both ZIP and LZW are lossless compression? They do not degrade the file at all as no information is lost it is just stored more efficiently. The only practical difference between saving a tiff with compression set to NONE and set to LZW is file size and save time.

A very simplifed example of how lossless compression manages to do this is to think about an image that is 100x100 and all solid black, just a black square. If you save this as a un-compressed tiff it will save a file that records the colour of every single pixel as black and that pixels position. If you save it with LZW compression it will save something like "black - 100px across 100px down".

[mikias]

I like the way you teach me!!!
Thank you!

[Barbarian]

Well having read the asnswer to this Q, with all respect to the writer, i have one more question....How can converting an image to CMYK before saving it to TIFF save information when the colour gamut of CMYK is much less than RGB.....

[PS 911]

Saving a compressed TIF from a JPG file is pointless. So, unless you're working with raw Photoshop files, saving as TIF will not be an advantage. Let's assume you are indeed working with Photoshop files.

Saving as a TIF gives you three options in image compression:
1) NONE
2) LZW
3) ZIP

Make sure the image mode is set to CMYK, and NOT "Indexed Color" ... while you can save an indexed color image to TIF, it's not recommended.

To retain ALL of the fidelity of the image, check the "NONE" setting. This might result in a very large file, but you'll retain all of the sharpness.

You should also flatten the file before saving, and use "Save As..." so the original file stays untouched.

If "Layer Compression" is not grayed out, that means you still have layers in the file, and you should use RLE compression.

Why you just started having the problem is a factor we cannot guess. Perhaps just the recent images? Or, perhaps the preferences got reset? Or, perhaps you've been saving over the same file, each time losing image quality?

Let us know how it comes out.

Good day. Photoshop well.

[Daitenshi]

Do you use any kind of compression while saving your tiff files?

While uncompressed, tiff is a lossless format, so the problem wouln't lies there. Can you reproduce this problem using other formats such as jpeg or eps?