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DPChallenge Forums >> General Discussion >> TIFF file compression question
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10/11/2017 12:44:15 PM · #1
Hoping someone can shed some light on this.

I'm trying to get some image files prepared for a friend to print and want to save them as TIFFs. Problem is the images are being printed at Costco whose max file size is 95mb but the files I have are 324mb. I tried saving them as TIFFs with LZW compression but it only lowered the file size to 317mb. Is there a way for me to get the file sizes down to around 90mb without losing too much data? I tried saving one as a jpg but it made it 9mb so I know it's losing a lot of image quality.

If the specifics are needed, they're 300dpi and 6000x9000 pixels and will be printed on metal.

Any help appreciated.
10/11/2017 12:54:00 PM · #2
How large is the final print?

An uncompressed TIFF at those dimensions should "only" be about 154MB -- is your image in 16-bit mode? If so, start by converting to 8-bit ...

FWIW I print TIFFs to Costco all the time ... I thought their max file size was more like 35MB, so it's good to hear it's larger now.

Also, you *may* be able to use a larger file if you are ordering directly from the in-store kiosk rather than on-line.

Message edited by author 2017-10-11 12:57:19.
10/11/2017 01:04:26 PM · #3
Thanks for the quick answer, Paul. The final print size is 20"x30".

The file was in 16bit mode so changed it to 8bit. I tried saving on with no compression but it was still too big (162mb). Saved another one with LZW compression which brought it down to 35mb. Will changing to 8bit and using LZW compression have any affect on the image quality? If not, then that would be perfect.
10/11/2017 01:26:05 PM · #4
If you really want to check the quality, copy out similar sample sections from the 8-bit and 16-bit versions and look at them side-by-side at 100% view. Personally, I've never been able to see the difference, and I doubt most people viewing the print will be able to either.

Even at 8-bit there are 16.7 million "possible" colors available -- I think most people can distinguish only a few thousand discrete shades -- the color gamut of CMYK (how magazines are printed) is considered to be "only" about 7000 colors.

The LZW compression will not affect image quality as it is lossless; FWIW if you are using a newish version of Photoshop I'm told that the highest-quality JPEG setting is also lossless, though I still prefer using TIFF myself whenever possible.
10/11/2017 01:33:52 PM · #5
Cool, thanks Paul. I'm sure my friend won't be able to tell any difference between 16 and 8 bit, I can't really tell. They're ordered. Thanks for your help.
10/11/2017 01:38:32 PM · #6
Late to the party, but just chiming in to say that for prints, there will be almost no difference between 8-bit and 16-bit files. The only time I'd be careful with 8-bit is when there is a solid-color sky with almost no gradient; 8-bit color can have a little bit of banding, but even that can be minimized by retaining 16-bit information until finally saving for output.

Edit to add:
TIFF compression is always lossless, unlike JPEG compression.

Message edited by author 2017-10-11 13:39:21.
10/11/2017 01:54:23 PM · #7
Originally posted by Cuttooth:

Cool, thanks Paul. I'm sure my friend won't be able to tell any difference between 16 and 8 bit, I can't really tell. They're ordered. Thanks for your help.

You're welcome -- glad it was something I actually know about!

FWIW if you (or anyone) ever have a similar issue, it would help to post at least a small version of the image in question, as compression results can be image-dependent -- the more detail and colors the less effective the compression will be.
10/11/2017 02:09:42 PM · #8
even later to the conversation................

I don't think in a print you would notice any difference if you printed your TIFF and JPG. If you work from the RAW file the entire time (or even going into PSD) and only output the JPG to print, you will not see any difference.
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