A question of quality--jpeg back to tiff

[mishahonu]

Hi There,

I am in charge all production aspects of a stock photo library. Due to an unfortunate backup error, our company has lost nearly 1,000 of our original tiffs. We do have all of these files as boxtop compressed jpeg's but we always keep copies of the tiffs.

My question is this:

Can I open our compressed jpegs (which open up to 50-75MB ) and then resave them as tiffs? From onscreen testing this seems fine as high as 300% but I have not tried a print test. Does this cause a great deal of damage or can I get away with it? If it does cause damage--what is it and where can it be seen?

Thanks for any and all advice!

--M

[bigcloud]

I can't be 100% sure but I believe that the damage is already done... so to speak. It's the saving as a JPG format that reduced the quality. Opening it as a TIFF shouldn't degrade it any further.

I'm sure there is much more to this answer (right or wrong) that others here can shed on this subject.

[mishahonu]

Right, the saving as a jpeg is where the loss of quality came in...but the tiffs are gonzo so it is either create new tiffs from the jpegs we have on file or spend a lot of money (we're talking thousands) and a lot of time rescanning and optimizing tiffs from slides.

Thanks for the reply

[Angusdog]

It would depend on the compression/quality trade-off when the JPGs were originally created - that's when the information would be lost. Opening them up and resaving them as TIFFs won't bring back any quality, JPG being a lossy format. However, I would imagine, being a stock photo library, you would have originally saved them with high quality / low compression and so the loss of quality will be negligible. Yes, technically some information has been lost, but you'd need a real expert to pick it and a real pedant to complain about it. Also, since I assume you supply them to clients as JPGs, who's going to complain?

[Scott W.]

Chances are if the jpg files were only saved once they can definitely be opened and re-saved as tiffs with very minimal quality loss. Compression of a single jpg saving will not damage a file too much provided the jpg quality setting is above 8. All online stock photography is marketed in jpg format with the understanding the files should be opened and re-saved as tiffs.

[pixel8]

While the jpegs are very likely top quality probably saved at maximum quality, and therefore perfectly fine to convert to a tif file that will not degrade further, there is still the problem with regards that you are selling these images from a stock library.

Which means that you run into a bit of trouble if you convert them to tif and then *sell them as tifs* because they aren't really and you could very well be done for false advertising. While the jpeg artifacts would not be visible in normal use or if published they would be visible if someone looked for them.

Remember that after converting to tiff that the image will still look like the original jpeg if it is blown up large enough to see the individual pixels. And those jpeg artifacts will always be visible in the tif file and any tifs made from it. If it is ever subsequently enlarged and sharpened those artifacts might become significant.