TIFF vs JEPG
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From: Scott W on 19 Apr 2006 12:04 Don wrote: > On Mon, 17 Apr 2006 19:15:11 -0400, Raphael Bustin <foo(a)bar.com> > wrote: > > >When you say things like this: > > > > "At 100% magnification (i.e. 1:1) even a JPG image at lowest > > compression (i.e. highest quality) stands out like a sore thumb > > when compared to the original." > > > >without qualification, that is misinformation, plain and simple. > > No, it's a simple fact. Explained thoroughly in subsequent messages > where I tried being conciliatory by not responding to your unwarranted > abuse. Unfortunately, your reply to that calm, factual response was > more unwarranted abuse. > > You were in the middle of a slug fest with our Mr. Noons so I may have > just caught some shrapnel the first time around (which is why I tried > being conciliatory and tried to calm things down) but the second batch > of abuses shows that initial outburst was not an accident. > > >I've offered several counter-examples to make my point. > >You've offered nothing of substance to defend yours. > > No, you did not. You offered highly processed images with no way of > confirming their veracity which all together made them meaningless in > this context. > > I explicitly specified parameters required for an objective test and > you violated virtually all of them in your "examples". Climbing all > the way back to those parameters now - and risking more abuse in the > process - at this point seems like an exercise in futility. > > The facts are all out there so let the reader decide for themselves. A > careful reader will arrive at meaningful conclusions, a careless > readers will spew nonsense. We've already seen examples of both. > And you have offer exactly what in the way of samples? How hard is this for you, show us a crop from a scan of yours that suffers visibly from being saved as a jpeg. Just how hard is that, after all you did say "At 100% magnification (i.e. 1:1) even a JPG image at lowest compression (i.e. highest quality) stands out like a sore thumb when compared to the original." So I did the test, here is my crop, one side was save as a jpeg the other is the original tiff. http://www.sewcon.com/tiff_vs_jpeg/compare.tif 2.8 MB Note not all browsers will view a 16 bit tiff and so this might have to be downloaded and viewed in something like Photoshop. This is an overview of the full image http://www.sewcon.com/tiff_vs_jpeg/overview.jpg And for those just for grins this is the full image as a fairly highly compressed jpeg http://www.sewcon.com/tiff_vs_jpeg/overview.jpg 13.5 MB Now you statement was that the jpeg would stand out like a sore thumb, it is clear to anyone who looks at the images that this in wrong. Not only does it not stand out like a sore thumb but I doubt there is anyone who can tell the difference even when zooming in on the image. Scott
From: rafe b on 19 Apr 2006 12:05 "Don" <phoney.email(a)yahoo.com> wrote in message news:jvhc42t6lj0bk3he9br0f6sf15nlk6vkhi(a)4ax.com... > No, you did not. You offered highly processed images with no way of > confirming their veracity which all together made them meaningless in > this context. Highly processed? Only for Noons' benefit, because it seemed he wanted "upsampled" versions (in his words: "Now, crop the JPEG and increase its size...") I started with images straight off the scanner. They can't be any more raw than that, Don. In fact, the images I linked to weren't created for you, they've been up on my "snippets" website for many months, specifically as a counterexample for those who make the same erroneous claims that you do. Again, you've contributed nothing but words to this thread. How about some examples to illustrate your points? Oh, right. You can't, of course, because your points are bogus. rafe b www.terrapinphoto.com scan snippets [now includes Epson V700] www.terrapinphoto.com/jmdavis
From: Scott W on 19 Apr 2006 12:07 Don wrote: > On 18 Apr 2006 14:34:56 +0200, Ole-Hjalmar Kristensen > <ole-hjalmar.kristensen(a)substitute_employer_here.com> wrote: > > >If you know where to look you will definitely see JPEG artifacts at a > >100% zoom. > > Exactly. > > >Just look at sharply defined diagonal lines, and it's easy > >to see the JPEG compression at work. > > That's one example. Another one is areas with lots of high contrast > detail where the 8x8 pixel JPG squares are as plain as can be. So post a tiff of your image that has this high contrast, just how hard is that? Scott
From: rafe b on 19 Apr 2006 12:10 "Don" <phoney.email(a)yahoo.com> wrote in message news:hbic42pa6s8mt023sd4s3j07ugsra67lkp(a)4ax.com... >clearly visible JPG artifacts at 100% are a > self-evident, axiomatic fact. In your universe, maybe. Not in mine. rafe b www.terrapinphoto.com
From: Bruce on 19 Apr 2006 12:01
Don, Yes, everyone agrees that with high compression JPG artifacts can be objectionable. But the point is that at low compression the quality can be so good that any data loss is imperceptible even after zooming in. Your answer when shown examples of this is to repeatedly accuse them of lying (you question the "veracity" of the examples) and then to attack them for taking offense to your accusations. The fact is that if you need to save a photographic image to a limited file size you will always get a better quality image from a JPG than a TIF. For example, to fit 100 large images on a CD, with quality JPGs you could use higher DPI (a very perceptible difference) than you could with TIFs. And Don, anyone watching sees the pattern where you provoke attacks and then feign innocence. In this case, if you don't like the data they show, maybe you should try and reproduce their results before publicly announcing (on theoretical grounds) not only that they are wrong, but that they also must be purposely lying. Don wrote: > On 18 Apr 2006 14:34:56 +0200, Ole-Hjalmar Kristensen > <ole-hjalmar.kristensen(a)substitute_employer_here.com> wrote: > >> If you know where to look you will definitely see JPEG artifacts at a >> 100% zoom. > > Exactly. > >> Just look at sharply defined diagonal lines, and it's easy >> to see the JPEG compression at work. > > That's one example. Another one is areas with lots of high contrast > detail where the 8x8 pixel JPG squares are as plain as can be. > >> But I agree, I will not matter at >> all for the content of the image. >> I file everything as maximum quality JPEG. > > Both of those are statements of subjective opinion (i.e. a reflection > of how much one values image content). I never talk about that because > that not only depends on the context but each person has their own > individual requirements. I only talk about objective facts and, as you > yourself confirm, clearly visible JPG artifacts at 100% are a > self-evident, axiomatic fact. > > Don. |