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Discussion Starter · #1 ·
Does anyone know why tiff files become corrupt. I scan some old pix as tiff's and worked with them in Photo Shop. Some I worked with in Paint Shop Pro. Now I can't open them in either program. Message says "The specified file cannot be identified as a supported type." or "It is not the right kind of document" These files worked for awhile - I was able to open them and work with them. So what could happen all of a sudden??? I am using a Dell XPS 600 with 2Gig of Ram; PhotoShop CS2 and Paint Shop Pro X and XI. Help please.
 

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What file type were they saved as after you fiddled with them

Do they open in explorer?
 

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When I get that message it is always because something has happened to the file extension. Make sure the very last thing in the file name is either .tif or .tiff.

Something else that could possible happen is that you save a tiff with layers and then try to open the file in a program that can't handle the layers. I haven't tried it, but it could be possible that PSP can't handle a tiff with layers from Photoshop. If you saved layers try the program you saved from to open it. If that works, flatten the image before saving it. Better to save as a proprietary file from Photoshop or PSP if you are saving layers.
 

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Discussion Starter · #5 ·
Possibly I did save the files with layers, don't remember - but these particular files won't open in any software now. I let the program create the extension, I never change it. This really worries me about future photos I scan and work on. If I cannot open them and no longer have the original - I'm in big trouble. Need to understand what I did so I don't do it again.
 

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I'm just curious: I'm assuming your original photos are either .jpg or .bmp which you open up in Photoshop or Paintshop. Why, for example, after opening the image in Photoshop, do you not save the file as a .psd file? And before you open the image in either program, copy your original photos to a CD or other media to save them.
 

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Discussion Starter · #7 ·
These photos are scanned to tiff and were backed up as such. Or were scanned to jpegs and changed to tiffs. I guess I was thinking they were interchangable between different software if left as tiff rather than the program's default format. I never opened one of these photos in a different software if it had layers. I worked on it in the original program. But months later when I went to open one of these files (flattened or one layer only) they wouldn't open in any software. Messages of corrupt files or corrupt headers. I hope this is clear
 

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Are these the only type of files that you've had problems with or are other files in other programs not readable either? I'm not sure what I can tell you to help you with your current dilemma, but use this methodology: Always keep a native copy of the file in whatever program you're using—Photoshop or Paintshop Pro—and if you need a TIF or other format, save a copy of the file in that format. You will always have a "work" file (the native file) and a "finished" file. If someone goes wrong with the finished file, you can always open the native and create another.
 

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Discussion Starter · #9 ·
I think that is good advice -- to keep a native copy. I have only had problems with tiff files - but that is pretty much the only format I use. If editing scanned photos (very old and damaged) or embellishing contemporary photos (again scanned) is there a preferred format to use??? These are for print AND archival purposes.
 

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Sorry so long—been away from my computer. Seems to me like you will need that "middle balance." When you say "print" do you mean inkjet/laser or are these going to a print shop for offset press printing? If it's "just" inkjet or laser, 300dpi is a good mid range for both your purposes. If it's going to press, depending on how large the image will print, it may need to be 1200dpi or larger. The most important thing is "capture." Take your photos in high resolution; you can always downsize them as necessary and you will have a sharper, more detailed image. If captured at low-rez, the quality can be tweaked but it won't have the clarity of an image taken at hi-rez. If archiving and printing, you are going to have to find a balance between managable file size and clarity of image.
 

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Oh—as far as a preferred format, again, the purpose can help determine that. I would guess that for your purposes, jpg, tif, or bmp files will be fine. If going to offset press, I would use postscript format (eps). If it indeed is going to offset press, the best thing to do is discuss it with the print shop—they will be your best advisors. If not, the most common image formats are ones mentioned above.
 

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Discussion Starter · #12 ·
I sometimes send my files to a lab if I am composing a poster or a piece with multiple photos or is larger than my printer can handle. Otherwise I use an inkjet printer and the format is tiff because it's lossless - is there a benefit to a bmp or other format (not jpeg) if I am doing the printing. So far the clarity has been very good with tiff but don't know enough about other formats.
 

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Okay, a few things.

First of all, TIFF's are not necessarily lossless -- the TIFF format supports various types of lossy and lossless compression depending on the options you select when you save the image. You seem to know what you're doing, so I assume you're selecting a lossless type of compression, but I just wanted to point that out.

Secondly, Ron, when you are referring to image resolution, you should be talking about pixels per inch (ppi), not dots per inch (dpi). The dpi measurement refers to print resolution -- it's dependent on the printer and has nothing to do with the image.

Thirdly, 1200ppi is overkill for most printing applications. Printers will rarely ask for more than 300ppi for a typical 175 line screen offset print. In fact, 300ppi is pretty much a standard in the print industry, with many exceptions of course.

Fourthly, no one is printing anything here, so I don't know how that even came up :)

Sneezy, a high-quality JPEG format is sufficient for archiving photos in about 99% of cases, especially for home use. The artifacts created by JPEG compression are practically nonexistent in a large image saved at the highest quality. BMP is way too large.
 

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Okay, my background is in offset and layout and design—I'm not the photographer. The images that usually make it to me when I'm doing that kind of work are hi-rez and usually require little work, perhaps some color correction but that's it. And Sneezy said that these photos will be printed. And, in offset, it depends on the media and the size of the image. If I'm doing a poster sized photo on coated gloss, that image will be output at a minimum of1200 dpi, 150 to 188 lpi (ripped halftone output to film, usually an Agfa 2000). 300 dpi would be sufficient if you're talking about an image no larger than 8 to 12 inches especially if being prepared to print on newsprint or another light, uncoated medium. But you're right that the image itself should be "measured" in ppi.
 

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It would be the reverse, actually. Larger prints usually have a lower dpi because they are viewed from farther away... a poster is viewed at a few feet or more, not a few inches like a magazine. Also, in regards to the image itself, if you print a given image at a larger size, it will have a lower ppi, not a higher one. And I'm not sure where you would ever find a 1200ppi poster-sized photo, because even a 10MP camera will only give you about a 100ppi (or less) image for a poster-sized print :)
 

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Discussion Starter · #16 ·
So back to my problem. I scan old (50-100 year old) photos and restore them. I use PhotoShop for most. On occasion I've used PaintShopPro for certain issues. I have no problem with print clarity. Projects turn out fine. Also using contemporary photos, I create my concept of art. I have been on occasion unable to open some tiffs (error messages stating they are not the correct file for the program or they have a corrupt header) and I am trying to figure out what I may have done to cause this problem. I Don't think I was trying to open a file that had layers created in the opposite software. They were either flattened first or had only one layer to begin with. Is it possible they were inadvertently saved to mac? Would this even create a problem??? Is a file saved as a tiff in PhotoShop not always able to open in another software that is supposed to handle tiffs too?? How careful do I have to be about working across software if they can both work with tiffs?

Also the size of the file isn't an issue - but always the quality is paramount. My question earlier was "Is there a "better" format to use when doing this kind of work than a tiff file?
 

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Most of your questions have already been addressed. TIFF's are well known for having compatibility problems. It's a very open-ended file format with many variations, and a lot of programs create proprietary TIFF's that can't be read with other software. If you save it with Photoshop, open it with Photoshop. If you save it with Paint Shop Pro, open it with Paint Shop Pro. Other than that, there's not much you can do, except (as you already mentioned) save them with the PC byte order and with no compression to minimize incompatibility.

PNG would be my first choice if I wanted lossless compression, but personally, I'd stick with JPEG.
 

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dpi and ppi are probably the most missused/understood terms in digital world to date period... If a print shop requires 300 dpi...go to another shop... that shop is in the dark ages...

here is a decent link to understanding it...

Hi erick295... I had a great link but of course I can't find it...

Try this one... http://en.wikipedia.org/wiki/Dots_per_inch

read thru including the external links at the bottom of the page...
 

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Discussion Starter · #19 ·
I'm not sure why you think most of my questions had been addressed - but in any event if tiff files are known to be problematic - then that is the most definitive information I have received. I didn't know that. I was beginning to guess that each program was creating their own version of a tiff - but this is the first I've heard it.
Thanks.
 

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Hi Sneezy

I'm sure it's of no consulation but I have never had a trouble with Tiff files...

I shoot raw/jpg with my camera... I convert the raw to tiff and save as tiff... They open in both Photoshop CS2 as well as PaintShopPro 7 which is the newest version I have... They also open in Irfanview which I have, but don't use much...

buck
 
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