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 05/05/2008 09:28:39 PM · #1
I save most of my edits as flattened TIFFs, at 350 dpi, 20 in x 30 in.
The resulting file sizes range from about 230 MB to 550 MB.
Does this seem right or is it higher than it should be?

(Thanks for responding).
 05/05/2008 09:38:18 PM · #2
hmm...busted post.

Message edited by author 2008-05-05 22:16:07.
 05/05/2008 09:49:16 PM · #3
20in x 350pix/in x 30in x 350pix/in x 3colors x 2bytes/color = 441MB, assuming no compression. So your number seem high, unless the tiffs have a 2byte alpha-channel, that would bump the uncompressed size up to 588MB. With lossless compression you could be getting up to a factor of 2 compression, so that would explain the range in size you are seeing.

BTW, have you tried some of the better wavelet compression methods, like JPEG2000 and Microsoft's HD Photo? You can get significantly more compression with absolutely no perceivable compression artifacts. I know disk-space is cheap, but those are some mighty large files :-)
 05/05/2008 10:12:02 PM · #4
Originally posted by magnus:
20in x 350pix/in x 30in x 350pix/in x 3colors x 2bytes/color = 441MB, assuming no compression. So your number seem high, unless the tiffs have a 2byte alpha-channel, that would bump the uncompressed size up to 588MB. With lossless compression you could be getting up to a factor of 2 compression, so that would explain the range in size you are seeing.

BTW, have you tried some of the better wavelet compression methods, like JPEG2000 and Microsoft's HD Photo? You can get significantly more compression with absolutely no perceivable compression artifacts. I know disk-space is cheap, but those are some mighty large files :-)


I'm just a one-headed peasant, 2bytes alpha short of any compression. JPEG2000 sounds JPEG to me which is lossy. Microsoft bloats me, altho I'm clueless with regards to HD Photo. I could be intrigued by wavelets, perhaps.

05/05/2008 10:15:32 PM · #5
Originally posted by CEJ:
.tiff files are very large. Depending on the use of the file, perhaps lower the .dpi? If it is not going to print no need for a 350 dpi file. Even if it is, 300 should be more than sufficient.


Are you sure? I don't, really, want to compromise any quality.
 05/05/2008 10:17:04 PM · #6
no...I know nothing...not a thing. Does this button turn it on or off?

Message edited by author 2008-05-05 22:18:09.
 05/05/2008 10:23:41 PM · #7
You started me thinking here, so I tried saving one image a few different ways:
.psd = 12.6MB
.tif (no compression) = 20.1MB
.tif (LZW lossless compression) = 7.2MB
.wdp (HDPhoto lossless compression "1.0 quality") = 5.7MB
.wdp (HDPhoto "0.9 quality") = 1.0MB

No matter how I zoom in and search around, I can't see any difference between the 1MB and the 20MB files. So I, for one, would use Microsoft's HDPhoto if I were faced with files this big. And no, I don't work for Microsoft, in fact I can't stand most of their products. But I'm in the image processing industry and I've read about the research that led to HDPhoto, and I must begrudgingly admit that they did a really good job on this one.
 05/05/2008 10:46:33 PM · #8
The linked page, still, doesn't give enough info to educate me, but I'm grateful nonetheless for the direction. I'm going to see what else I can find on it.
 05/05/2008 10:48:07 PM · #9
Originally posted by CEJ:
no...I know nothing...not a thing. Does this button turn it on or off?


Are you going to abandon me now altogether?
 05/05/2008 11:19:56 PM · #10
Originally posted by zeuszen:
The linked page, still, doesn't give enough info to educate me, but I'm grateful nonetheless for the direction. I'm going to see what else I can find on it.

Here's a couple of starting points. Bill Crow's blog (he's the program manager for HDPhoto), and an interview with him in PopPhoto. It was actually the blog that convinced me he had done his science right, in particular the Oct 20 '06 entry.

There is one other dimension to all of this: will you still find software to open your images 10 or 20 years from now? TIFF (even with LZW compression) is such a simple file format that it's practically guaranteed to be around for ever (lazy software developers rule!). JPEG2000 is complex, but it is a standard, so chances are pretty good that it'll be around for a while, if only as a niche product. So you may be able to open JPEG2000 photos in 10 years, but probably not with a Photoshop plugin. HDPhoto will either catch on and become a standard, or crash and burn. I'd still bet on it, but worst case you'll have to recode all your files in 5 years. If that happens and it's my fault, I'll just have fly out west and give you a hand (hey, I've never been to western Canada...)
 05/06/2008 12:03:17 AM · #11
Originally posted by magnus:
...Here's a couple of starting points. Bill Crow's blog (he's the program manager for HDPhoto), and an interview with him in PopPhoto. It was actually the blog that convinced me he had done his science right, in particular the Oct 20 '06 entry.

There is one other dimension to all of this: will you still find software to open your images 10 or 20 years from now? TIFF (even with LZW compression) is such a simple file format that it's practically guaranteed to be around for ever (lazy software developers rule!). JPEG2000 is complex, but it is a standard, so chances are pretty good that it'll be around for a while, if only as a niche product. So you may be able to open JPEG2000 photos in 10 years, but probably not with a Photoshop plugin. HDPhoto will either catch on and become a standard, or crash and burn. I'd still bet on it, but worst case you'll have to recode all your files in 5 years. If that happens and it's my fault, I'll just have fly out west and give you a hand (hey, I've never been to western Canada...)


Funny you linked Bill Crow. I was reading it (still am) at the time of your post.

I'm somewhat reserved about these formats. CS3 reads 'em but won't let us save in them. There's not much software with support, certainly nothing auntie Betty would ever use. OSX can display them, but when it does it looks radically different than via Microsoft's PS plugin, and I have to enter into a legal contract with M. to use it?

M. describes the format as twice as good as JPEG and comparable (that's all?) to JPEG2000. Is it as good as PSD/TIFF though? And what is optimum (Microsoft, quote/un-) dynamic range, equal to RAW?

Message edited by author 2008-05-06 00:07:30.
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