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Question

Tiff files are not uncompressed

Forum|Forum|3 years ago
March 28, 2022
4 replies
6011 views

Jorma Jokinen.

I have made a Family Tree chart in tiff format. Every time I get new information I open it in PS and do my editing. After repeating this tens of times the older parts of the chart are beginnig to seem more and more unreadable. Why this because tiff format is told to be uncompressed and loseless.

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T

Test Screen Name

Legend

"I open a picture in PS, edit it and save in tiff format in mode without any compression. Why it is not exatly the same picture that I had on the screen when I open it again? "

I think the results shown from your screen shots are clear. It is not the editing and saving of TIFF which causes the slow damage to the picture. You could open and save a TIFF a million or a billion times without any damage. The damage is, therefore, caused by the things you do when you're editing (not necessarily every time).

J

jazz-y

Legend

It seems to me that the problem is not related to the image format.

Your example looks like you first reduced the size of the entire image (or an individual layer) and then increased it. For example, I took your screenshot with good readable text, its size 576x801 px reduced it to 200x308 px, and then returned it to its original size using Preserve Details interpolation algorithm (Photoshop uses it automatically if you did not change the interpolation settings) . It can be seen that very similar distortions of letters to images have occurred (the difference is only in sharpness, I assume that you added it later).

TheDigitalDog

Inspiring

The TIFF format is always lossless, even if you pick one of the compression options which you may not want to do for support in other products and time lost compressing and uncompressing. A TIFF isn't a JPEG so no, you can open, edit and save without the same kinds of data loss as JPEG. Now unless you're re-editing high-bit data, edits can produce some data loss from the image editing itself but not in this case, due to you picking TIFF.

More here: http://digitaldog.net/files/TIFFvsPSD.pdf

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

davescm

Community Expert

"The TIFF format is always lossless"

That is not the case if you flatten an 8 bit image and save it as a TIFF using the jpeg compression option. Then the compression is lossy. If in doubt, try it, just Save As, choose TIFF and choose jpeg compression, setting the quality to low. On re-opening the TIFF file, the jpeg compression artifacts are obvious.

Dave

TheDigitalDog

Inspiring

I don't have such an option I can select.

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

T

Test Screen Name

Legend

Yes, the TIFF format is lossless UNLESS you choose the "JPEG" option on saving (that is, the JPEG option for saving TIFF).

Can you share a little cut off part of the family tree, with no complete personal info, to show us what the damage looks like?

J

JJo-45Author

Participating Frequently

Here is a pair of pictures. The older date is 15.09.2021 and the newer
22.02.2022.
Between these dates there has been numerous open and save actions.
Saving of the work file has always happened in uncompressed tiff format.
The size of whole chart in tiff format is 487 MB and in jpg format which
I have used when sending it to friends is 13 MB.

Conrad_C

Community Expert

My document size is 22526 px x 7559 px and resolution 96 px/inch.

The low resiolution is derived from the program (MyHeritage). I can´t get the family tree data as digital file but I copy it from the computer screen with screensaver. So My text is not text but letters are small picture images as all other elements like lines and pictures. Data boxes come from MyHeritage but placing the boxes to my cahart, drawing new lines and editing text inside boxes happens by enormous amount of copy and save actions.

@JJo-45 wrote:

The low resiolution is derived from the program (MyHeritage). I can´t get the family tree data as digital file but I copy it from the computer screen with screensaver. So My text is not text but letters are small picture images as all other elements like lines and pictures. Data boxes come from MyHeritage but placing the boxes to my cahart, drawing new lines and editing text inside boxes happens by enormous amount of copy and save actions.

OK. I see. That explains a lot. That means the quality of the family data depends on what is copied out of MyHeritage. It is too bad it doesn’t let you copy it as editable smooth text.

It also means how good it looks depends on the quality of the display on screen in MyHeritage. Does it let you zoom in or enlarge the text? If it did, that would help preserve the quality. Because you have to copy and paste the info as images in that way, it will be hard to improve the quality.

That still does not explain why you think the quality is degrading with more saves. The TIFF format should still not do that, even if LZW or ZIP compression is used because they are lossless. But again, quality could go down if the pasted images are resized.

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