[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: >Although I concur with all you have said, I have to wonder if the publicist >and publisher are requesting jpeg files rather than lwz compressed TIFF >files out of force of habit, lack of knowledgabout the ability to compress >TIFFs using the lwz compression which is as good if not better than the JPG >compression at levels 10-12, or a lack of any real concern over quality of >the file they are getting. Hi Laurie, Is it not lzw compression instead of lwz? In any case, does the amount of reduction in the file size using lzw compression vary considerably with the content? The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Your comment that lzw compressed TIFF files are as small as JPGs made me wonder if you are working with graphic files and if they offer better compression than photos. Later, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
Date sent: Sun, 09 Jun 2002 15:09:58 -0400 Send reply to: [EMAIL PROTECTED] From: "Johnny Johnson" <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) > At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: > > >Although I concur with all you have said, I have to wonder if the publicist > >and publisher are requesting jpeg files rather than lwz compressed TIFF > >files out of force of habit, lack of knowledgabout the ability to compress > >TIFFs using the lwz compression which is as good if not better than the JPG > >compression at levels 10-12, or a lack of any real concern over quality of > >the file they are getting. > > Hi Laurie, > > Is it not lzw compression instead of lwz? yes > In any case, does the amount of > reduction in the file size using lzw compression vary considerably with the > content? yes; if there are many pixels of same color, image will compress more. The reason I ask is that I just compared a scanned photograph of > 3591 X 5472 pixel size saved in several formats. The results were: > > TIFF36,498 kb > TIFF with lwz compression 36, 523 kb > JPG @ Photoshop level 1217,633 kb Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes)
At 05:32 PM 6/9/02 -0400, Mac wrote: >Wow, are you sure? The LZW TIFF was *larger*? >That's unusual. Hi Mac, Thanks for asking - it looks like the original TIFF file that I grabbed must have already been saved with lwz compression. So, I did the experiment again using a fresh scan of a different slide with the following results: TIFF: 56,264 kb TIFF with lzw compression: 35,364 kb JPG with Photoshop level 12:18,453 kb So, in both this case and the previous one, the JPG with level 12 compression is ~ 1/2 the size of a TIFF with lzw compression. Thanks again for bringing my mistake to my attention, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
It's not that unusual, though I don't recall why, and LZW compression will not reduce file size nearly as much as JPG Maris - Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 09, 2002 4:32 PM Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) [snipped] The reason I ask is that I just compared a scanned photograph of > 3591 X 5472 pixel size saved in several formats. The results were: > > TIFF36,498 kb > TIFF with lwz compression 36, 523 kb > JPG @ Photoshop level 1217,633 kb Wow, are you sure? The LZW TIFF was *larger*? That's unusual. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
> yes; if there are many pixels of same color, image > will compress more. And that is almost never true for real-world photographs, although it is certainly true quite often for computer-generated images such as diagrams and the like. > Wow, are you sure? The LZW TIFF was *larger*? It can be if there is a _lot_ of detail. In a lossless compression scheme, the chances of a compressed image being _larger_ than the original are always equal to the chances of it being smaller, if the image is completely random. In practice, totally random images are scarce, but the more detail an image contains, the more closely it approaches randomness, and the greater the probability that the compressed file may actually be larger than the uncompressed file. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes)
Date sent: Sun, 9 Jun 2002 19:42:32 -0500 Send reply to: [EMAIL PROTECTED] From: "Maris V. Lidaka Sr." <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) > It's not that unusual, though I don't recall why, and LZW compression will > not reduce file size nearly as much as JPG > > Maris Makes sense to me. Even at low compression (high quality) a JPEG is throwing away alot of similar color nuances. That's how it works. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen (was:Color spaces for differentpurposes)
>Is it not lzw compression instead of lwz? Yes, my fingers went faster than my mind when I wrote it. :-( >Your comment that lzw compressed TIFF files are as small as JPGs made me >wonder if you are working with graphic files and if they offer better >compression than photos. I must be candid and note that I was only repeating what others have said in other discussions of file compression techniques and their comparative advantages and limitations. I personally tend to use Genuine Fractals with photographic images and not JPEG or LZW. My experiences in doing some of my own testing suggests that (a) it depends on the image as to how comparable the size of the file will be upon compression using LZW vr JPEG at level 10-12, (b) the level of quality (i.e., degree of artifacting and degradation of the image) often is dependent on the degree of compression one uses when saving as JPEG such that the compression needed to produce sizable reductions in file sizes tends to result in a trade-off with respect to an increase in image degradation, and (c) certain image enhancements do prior to compression tends to effect the efficiency of the compression performed by the different compression operations. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Johnny Johnson Sent: Sunday, June 09, 2002 2:10 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen (was:Color spaces for differentpurposes) At 01:20 PM 6/9/02 -0500, Laurie Solomon wrote: >Although I concur with all you have said, I have to wonder if the publicist >and publisher are requesting jpeg files rather than lwz compressed TIFF >files out of force of habit, lack of knowledgabout the ability to compress >TIFFs using the lwz compression which is as good if not better than the JPG >compression at levels 10-12, or a lack of any real concern over quality of >the file they are getting. Hi Laurie, Is it not lzw compression instead of lwz? In any case, does the amount of reduction in the file size using lzw compression vary considerably with the content? The reason I ask is that I just compared a scanned photograph of 3591 X 5472 pixel size saved in several formats. The results were: TIFF36,498 kb TIFF with lwz compression 36, 523 kb JPG @ Photoshop level 1217,633 kb Your comment that lzw compressed TIFF files are as small as JPGs made me wonder if you are working with graphic files and if they offer better compression than photos. Later, Johnny __ Johnny Johnson Lilburn, GA mailto:[EMAIL PROTECTED] Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes)
Date sent: Sun, 09 Jun 2002 18:59:45 -0400 Send reply to: [EMAIL PROTECTED] From: "Johnny Johnson" <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes) > At 05:32 PM 6/9/02 -0400, Mac wrote: > > >Wow, are you sure? The LZW TIFF was *larger*? > >That's unusual. > > Hi Mac, > > Thanks for asking - it looks like the original TIFF file that I grabbed > must have already been saved with lwz compression. So, I did the > experiment again using a fresh scan of a different slide with the following > results: > > TIFF: 56,264 kb > TIFF with lzw compression: 35,364 kb > JPG with Photoshop level 12:18,453 kb > > So, in both this case and the previous one, the JPG with level 12 > compression is ~ 1/2 the size of a TIFF with lzw compression. > > Thanks again for bringing my mistake to my attention, > Johnny That makes more sense. Contrary to what Anthony Atkielski wrote, I have NEVER seen a LZW Tiff come out larger than an uncompressed one, regardless of exact pixel content. I have also never seen a compressed TIFF come out equal to or smaller than a JPEG at the same pixel dimensions, regardless of how how the quality setting of the JPEG. The only time I've seen a compressed file come out larger than a non-compressed one is when using .zip on a JPEG. Mac McDougald -- DOOGLE DIGITAL 500 Prestwick Ridge Way # 39 - Knoxville, TN 37919 [EMAIL PROTECTED] 865-540-1308 http://www.doogle.com Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen(was:Color spaces for differentpurposes)
I have occasionally gotten JPEGs that were larger than the original, uncompressed TIFF file if the file contained a lot of detail and had been heavily sharpened, and the JPEG compression was set at maximum quality / minimum compression. So it can happen, but in my personal experience only rarely. - David -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Sunday, June 09, 2002 11:43 PM [snip] The only time I've seen a compressed file come out larger than a non-compressed one is when using .zip on a JPEG. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] RE: Archiving and when to sharpen(was:Color spaces for differentpurposes)
>Since JPEG is lossless and TIFF is not, this is to be expected. Don't you have this reversed? My understanding is that JPEG is lossy while TIFF with LZW is lossless. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Anthony Atkielski Sent: Monday, June 10, 2002 4:05 PM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes) Mac writes: > Contrary to what Anthony Atkielski wrote, > I have NEVER seen a LZW Tiff come out larger > than an uncompressed one, regardless of exact > pixel content. Real-world photographic images rarely come out larger after compression, but I can generate such an image in about 30 seconds in Photoshop. I did that just now and got one that is 20% larger after compression. > I have also never seen a compressed TIFF > come out equal to or smaller than a JPEG > at the same pixel dimensions, regardless of > how how the quality setting of the JPEG. Since JPEG is lossless and TIFF is not, this is to be expected. > The only time I've seen a compressed file come > out larger than a non-compressed one > is when using .zip on a JPEG. JPEGs are virtually incompressible to begin with, which is why attempts to losslessly compress them further will often produce larger files. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
[filmscanners] Re: Archiving and when to sharpen(was:Color spaces for differentpurposes)
Laurie writes: > Don't you have this reversed? My understanding > is that JPEG is lossy while TIFF with LZW is > lossless. Yes, I do, sorry. Fortunately, you understood what I meant, not what I wrote. I was in a rush, as usual. Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
