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#171
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Mike Engles wrote:
ftp://ftp.alvyray.com/Acrobat/9_Gamma.pdf Yes, very good information, from a rather heavy weight professional, his Bio btw is at: http://alvyray.com/Bio/default.htm Even if it was written in 1995 it is perfectly valid today (only that in case the image has an embedded ICC profile we need not to *guess* the transfer function, ICC color-management was not very popular at that time). They must be transmitting/recording in at least 18 bit. That is the bit level that Chris Cox et al say is the minimum necessary for linear images, without gamma encoding. No more bits are necessary for digital imaging than what the sensor of the acquire device is able to provide (according to it's S/N ratio) in other words there is no need to store pure noise. Say you buy 12 eggs, then you do not need a trailer truck to bring them home. And these days the so called pro scanners and pro digital cameras can not reach even 10-bit. Ther real pro devices (like the EverSmart Supreme ll scanner that has cooled CCD) can do nearly 12-bit. And the so called banding issue in 8-bit/c is linear is enormously exaggerated, it is in fact quite an academic case:Here is an example from a thread on my forums: 16-bit/ edit: http://www.aim-dtp.net/aim/temp/sad_...edit-16bit.jpg 8-bit/c edit http://www.aim-dtp.net/aim/temp/sad_...-edit-8bit.jpg The original was a linear converted RAW from D60. You can read the details from the thread:'Linear workflow and 8bit/channel' if you like to go there. Rather demanding picture in regards to the horrible banding issue, can you see *any* problems in the 8-bit/c edit? It does seem that what we have today is two types of digital imaging. One is the truly scientific one that uses ALL linear data. Yes, the scientific imaging is done in linear. The other is a convenient engineering one that delivers the goods simply, by pre compensating the linear data to display on non linear displays. This the _easy solution_ for the ordinary consumers. It is *not* an engineering issue but a marketing issue.The industry simply needs a way to sell the digital imaging gadgets to the mass market consumers without stressing the consumers with the workflow issues. And the third type of digital imaging is the high end professional imaging that you see in the better magazines etc. It is still done in linear domain like it has been done for the past 30 years. For the very reasons Dr. Alvy Ray Smith lists on his above mentioned memo like "all computer graphics computations assume linear images", this includes Photoshop CS also. When the computations are applied over gamma compensated image data there will be the Gamma Induced Errors. Timo Autiokari |
#172
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Mike Engles wrote:
ftp://ftp.alvyray.com/Acrobat/9_Gamma.pdf Yes, very good information, from a rather heavy weight professional, his Bio btw is at: http://alvyray.com/Bio/default.htm Even if it was written in 1995 it is perfectly valid today (only that in case the image has an embedded ICC profile we need not to *guess* the transfer function, ICC color-management was not very popular at that time). They must be transmitting/recording in at least 18 bit. That is the bit level that Chris Cox et al say is the minimum necessary for linear images, without gamma encoding. No more bits are necessary for digital imaging than what the sensor of the acquire device is able to provide (according to it's S/N ratio) in other words there is no need to store pure noise. Say you buy 12 eggs, then you do not need a trailer truck to bring them home. And these days the so called pro scanners and pro digital cameras can not reach even 10-bit. Ther real pro devices (like the EverSmart Supreme ll scanner that has cooled CCD) can do nearly 12-bit. And the so called banding issue in 8-bit/c is linear is enormously exaggerated, it is in fact quite an academic case:Here is an example from a thread on my forums: 16-bit/ edit: http://www.aim-dtp.net/aim/temp/sad_...edit-16bit.jpg 8-bit/c edit http://www.aim-dtp.net/aim/temp/sad_...-edit-8bit.jpg The original was a linear converted RAW from D60. You can read the details from the thread:'Linear workflow and 8bit/channel' if you like to go there. Rather demanding picture in regards to the horrible banding issue, can you see *any* problems in the 8-bit/c edit? It does seem that what we have today is two types of digital imaging. One is the truly scientific one that uses ALL linear data. Yes, the scientific imaging is done in linear. The other is a convenient engineering one that delivers the goods simply, by pre compensating the linear data to display on non linear displays. This the _easy solution_ for the ordinary consumers. It is *not* an engineering issue but a marketing issue.The industry simply needs a way to sell the digital imaging gadgets to the mass market consumers without stressing the consumers with the workflow issues. And the third type of digital imaging is the high end professional imaging that you see in the better magazines etc. It is still done in linear domain like it has been done for the past 30 years. For the very reasons Dr. Alvy Ray Smith lists on his above mentioned memo like "all computer graphics computations assume linear images", this includes Photoshop CS also. When the computations are applied over gamma compensated image data there will be the Gamma Induced Errors. Timo Autiokari |
#173
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Please do not feed the troll.
In article , Timo Autiokari wrote nothing useful: |
#174
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Please do not feed the troll.
In article , Timo Autiokari wrote nothing useful: |
#175
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Chris Cox wrote:
Please do not feed the troll. In article , Timo Autiokari wrote nothing useful: I respectfully disagree. Timo's contributions to the group are certainly of value. I think he deserves further credit for not responding in kind to some of those who criticize him personally. -- Mike Russell www.curvemeister.com www.geigy.2y.net |
#176
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Chris Cox wrote:
Please do not feed the troll. In article , Timo Autiokari wrote nothing useful: I respectfully disagree. Timo's contributions to the group are certainly of value. I think he deserves further credit for not responding in kind to some of those who criticize him personally. -- Mike Russell www.curvemeister.com www.geigy.2y.net |
#177
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Kibo informs me that Chris Cox stated that:
They're part of the SDK, and always have been. (and don't get me started on why the SDK isn't free) *mutter* I can guess. It'd obviously be inappropriate for you to discuss that issue here, but if you feel the urge to vent about it, I'd be most interested in discussing it via email. (This email address will reach me, BTW) Photoshop RAW is just bytes - no header, no documentation. Ah. In that case, I should be able to figure the details out for myself. Much obliged for the hint, Chris. And if you get a chance to pass on on a message to the genius who decided to put a price-tag on the SDK (despite the fact that Adobe has the sense to provide the PostScript, etc doco's for free download), please inform him/her that that policy has cost them a potential plugin developer, because I refuse to pay a company money for documentation that I would need to enhance *their* product. Even *Microsoft* have finally realised that encouraging 3rd party developers is good business practice. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#178
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The pot is calling the kettle black again. Chris Cox' behavior was well
documented in this link: http://www.ledet.com/margulis/How_CM_Failed.pdf ============================= Is Color Management Rocket Science? In January, I was e-mailed some tough technical questions from a gentleman who was having trouble making the upgrade to PS 5. I wondered why he had not asked them of Adobe. It turned out that he had. Chris Cox, an Adobe programmer, had responded on-line as follows: “Start by going to the Adobe web site and reading the PS 5 technical guides (oh, and get the 5.0.2 update).” The correspondent replied, “I’ve read them several times and still have the many questions described (and have 5.0.2).” To that, Mr. Cox’s answer was, “Well, since they clearly answer the ques-tions you posed, I have to wonder what’s wrong.” The answers are not there. And the man Mr. Cox had blown off not only was a Photoshop instructor with a graduate degree in mathematics but, get this, a rocket scientist, claiming to have played an important design role in the launch interface for the Apollo program. The rocket scientist, having stated these credentials, shot back, “I don’t know what your problem is. Your first response to my questions showed you didn’t read my message, which clearly indicates that I had read the documents you cited. Your second reply, in addition to being totally insulting, reinforces that you didn’t read the original message as there are many, many questions not addressed by Adobe. Moreover anyone who claims that the Adobe documents answer my questions clearly is either an expert who doesn’t understand the difficulties others have or someone who doesn’t understand the difficulties of the subject…These are not straightforward issues...So, Chris, be careful with your snivelling, ignorant remarks.” At that point, the two wisely took their conversation off-line, but not before other readers chimed in. One wrote. “I agree with [the rocket scientist]. As a Photoshop heavy user since version 1.0, I have been struggling and struggling with ICC color profiles for a while now and I just don’t get it! I’VE BEEN TO ADOBE ONLINE....I’m really ****ed at Adobe. I have ruined—by embedding profiles—a bunch of scans that I don’t know how I’m going to fix…I’m sure the Adobe engineers had their heads in the right place, but I’ll be dipped in [doo-doo] if I can get my scanners, computers and printers to all work together. Sure I can go back to 4.0, but c’mon—I don’t think that’s the intent of Adobe—to send people reeling back-wards. Most people will not spend the 8-16 hours trying to write color profiles and run tons of expensive coated papers to master this crap. Let’s try to work together to share experiences and not just patly respond with trite comments.” You don’t need to be a rocket scientist to agree with that. —DM Mike Russell wrote: Chris Cox wrote: Please do not feed the troll. In article , Timo Autiokari wrote nothing useful: I respectfully disagree. Timo's contributions to the group are certainly of value. I think he deserves further credit for not responding in kind to some of those who criticize him personally. -- Mike Russell www.curvemeister.com www.geigy.2y.net |
#179
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The pot is calling the kettle black again. Chris Cox' behavior was well
documented in this link: http://www.ledet.com/margulis/How_CM_Failed.pdf ============================= Is Color Management Rocket Science? In January, I was e-mailed some tough technical questions from a gentleman who was having trouble making the upgrade to PS 5. I wondered why he had not asked them of Adobe. It turned out that he had. Chris Cox, an Adobe programmer, had responded on-line as follows: “Start by going to the Adobe web site and reading the PS 5 technical guides (oh, and get the 5.0.2 update).” The correspondent replied, “I’ve read them several times and still have the many questions described (and have 5.0.2).” To that, Mr. Cox’s answer was, “Well, since they clearly answer the ques-tions you posed, I have to wonder what’s wrong.” The answers are not there. And the man Mr. Cox had blown off not only was a Photoshop instructor with a graduate degree in mathematics but, get this, a rocket scientist, claiming to have played an important design role in the launch interface for the Apollo program. The rocket scientist, having stated these credentials, shot back, “I don’t know what your problem is. Your first response to my questions showed you didn’t read my message, which clearly indicates that I had read the documents you cited. Your second reply, in addition to being totally insulting, reinforces that you didn’t read the original message as there are many, many questions not addressed by Adobe. Moreover anyone who claims that the Adobe documents answer my questions clearly is either an expert who doesn’t understand the difficulties others have or someone who doesn’t understand the difficulties of the subject…These are not straightforward issues...So, Chris, be careful with your snivelling, ignorant remarks.” At that point, the two wisely took their conversation off-line, but not before other readers chimed in. One wrote. “I agree with [the rocket scientist]. As a Photoshop heavy user since version 1.0, I have been struggling and struggling with ICC color profiles for a while now and I just don’t get it! I’VE BEEN TO ADOBE ONLINE....I’m really ****ed at Adobe. I have ruined—by embedding profiles—a bunch of scans that I don’t know how I’m going to fix…I’m sure the Adobe engineers had their heads in the right place, but I’ll be dipped in [doo-doo] if I can get my scanners, computers and printers to all work together. Sure I can go back to 4.0, but c’mon—I don’t think that’s the intent of Adobe—to send people reeling back-wards. Most people will not spend the 8-16 hours trying to write color profiles and run tons of expensive coated papers to master this crap. Let’s try to work together to share experiences and not just patly respond with trite comments.” You don’t need to be a rocket scientist to agree with that. —DM Mike Russell wrote: Chris Cox wrote: Please do not feed the troll. In article , Timo Autiokari wrote nothing useful: I respectfully disagree. Timo's contributions to the group are certainly of value. I think he deserves further credit for not responding in kind to some of those who criticize him personally. -- Mike Russell www.curvemeister.com www.geigy.2y.net |
#180
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Chris Cox wrote in message ...
... (and don't get me started on why the SDK isn't free) Here are my theories: * so that Adobe can weed out people who want to use the SDK to write plugin hosts (not to mention other interoperative stuff like parse PSD format) * so there is a gate already in place for when the new plugin API is launched The timing of the retract was curious, in that it neatly divided developers from the information they needed to take plugins to OS X (unless they wanted to pay the money, somersault through the flaming hoops, wait for their application to be vetted, yadda yadda...) Shortly before the diktat came down to plug the leak, you can bet there was muttering in the halls, "Why did we -ever- give it away". --T Photoshop RAW is just bytes - no header, no documentation. Chris |
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