🚀 go-pugleaf

You know that assigning a profile and converting to a profile are two separate and quite different processes, don't you?

Yes, I believe a know the difference.

In simple terms, I believe that assigning a profile, assigns a working "set of colors" (color space) for the person who is correcting. It does not change the color value of the pixels, but is simply a visual reprsentation of the image when confined to the assigned colors. and by embedding it, the next user down the pike will know which defined "color set" was used to make corrections. Converting actually will map colors from one space to another and uses the actual destination spaces pixel values in the file.... right?

If this is the case....
I still ask the question above

ASSIGN VERSUS CONVERT TO PROFILE 

      > Why would the image (change when) assigning the profile, but look the
      same as the original when converting?




That behavior is 100% to be expected. I like to explain the difference between Assign Profile and Convert To Profile like this: <http://www.gballard.net/psd/assignconvert.html>

PROOF SETUP

Photoshop> View> Proof SetUp: Profile
AKA "Soft Proofing" is generally used to preview a target device profile (like a specific Printer/Paper/Ink profile).

In most cases, Photoshop's Soft Proofing feature is very confusing in the theory department unless we understand why we are using SoftProofing.

In this case, I would first get the Assign-Convert theory nailed down...

csullivan,

The only time you use assign is when some moron hands you an untagged profile and you need to make an educated guess as to which color space said moron was using when he/she created and saved the file.

CONVERT to profile strives to preserve the colors while changing the numbers. Assign maintains the numbers and changes/wrecks the colors.

Maybe this old post will help you:

Ram�n G Casta�eda, "Definitions for profiles" #3, 16 Nov 2008 5:17 pm </webx?14@@.59b70b5b/2>

I somehow missed that thread, Ram�n, but here is one of the best explanations I've read:

Eric Chan - 9:30am Nov 21, 08 PST (#71 of 82)
Camera Raw Engineer

I have not read the whole thread, but the easiest way to think of it is in terms of the language analogy.

Tagging/assigning is identification.

Converting means translation while preserving meaning.

Here's an example.

Suppose you hear a stream of words coming over the radio while driving your car. You don't understand it. Your friend sitting next to you says, "Oh, that sounds like Korean." That's tagging, or assigning. Your friend is identifying what the language is. There's no conversion/translation happening. Your friend may be correct, or incorrect. (For all you know, the real language might actually be Japanese.) Regardless, the central point is that this is what tagging/assigning means.

But now suppose you actually want to understand what those words mean (i.e., what the radio program is about). Then somebody has to translate it for you. This is "conversion." You ask your friend to translate the "Korean" to English, a language you do understand. What you hear from your friend are words in English, which are different from the original words coming over the radio (which are in Korean). But the meaning is the same (**). Going back to color management, "conversion" means that in general the underlying numbers change during the conversion process, but the color appearance stays the same.

Eric

(**) This assumes your friend actually knows Korean and translated it correctly.

Thank you to both of you for technical and non-technical. The analogy of language is very good and would also support the theory that once you have a "translation" (conversion) and you attempt to re-translate back or to a different language (profile) that something may be lost in the translation....

I do have a good understanding of Assign and Convert. Your information just supports that. What I did not know is how Photoshop uses previews.

What I thought was that if a had a ProPhoto RGB file and assigned Adobe RGB that the preview would reflect in gamut colors, which in turn, would look very bad given the differences in size of color space. Convert (From ProPhoto), would actually change the pixel values to fit inside of the gamut of the destination profile (Adobe RGB).

Why is it that:
If all colors in the image from ProPhoto fit inside of the Adobe RGB profile to begin with, that the preview would chaange dramatically. Is it due to the size of the gamut of ProPhoto (i.e. the distance between color values)?

and just for clarification of the preview mode. If I do assign Adobe RGB profile in this instance, why do I not get the choice of rendering intents? I am assuming that the preview is in gamut colors (and others are clipped?)

thanks

      > I do have a good understanding of Assign and Convert.




if you know (and have Honored) the Source Space in Photoshop, WHY are you still talking about ASSIGNING a different profile to it � it is kind of a pointless experiment once you understand the point

if you want to change the Source Space (Source Profile) -- CONVERT

if you want to "Soft Proof" a Target Profile/Space in Photoshop -- use View> Proof SetUp: Profile 

      > how Photoshop uses previews The file (the document Source Space) is
      independent of Photoshop:





The Color Management System CMS, Photoshop, ONLY uses the monitor profile for one thing: To PROOF source file on the monitor (the monitor profile has zero to do with how the file prints).

The Color Management System CMS, Photoshop, ONLY uses the printer (target) profile Print Space for one thing: To PROOF source file on the paper (the printer profile Print Space has zero to do with how the file looks on the monitor)...www.gballard.net/psd/cmstheory.html

      > once you have a "translation" (conversion) and you...re-translate back
      or to a different language (profile) that something may be lost in the
      translation....




EXACTLY

Conversions degrade color information...I like to keep my color conversions to an absolute minimum.

      I do have a good understanding of Assign and Convert.Yes, I believe a
      know the difference.




Are you sure? Your earlier explanation felt a bit muddled:

      In simple terms, I believe that assigning a profile, assigns a working
      "set of colors" (color space) for the person who is correcting. It does
      not change the color value of the pixels, but is simply a visual reprsentation
      of the image when confined to the assigned colors. and by embedding it,
      the next user down the pike will know which defined "color set" was used
      to make corrections. Converting actually will map colors from one space
      to another and uses the actual destination spaces pixel values in the
      file.... right?




I'm not sure. In actually simple terms, the difference is this, as others have pointed out and I'm just restating:

i Assigning a profile leaves the color numbers in the file unchanged, but changes their appearance (their "meaning" in device-independent terms).

i Converting to a profile changes the color numbers in the file, but keeps the appearance unchanged (except for gamut mismatches, in which case the rendering intent decides how the out-of-gamut colors in the source are mapped to the destination).

I think it's important to understand this distinction and be able to state it as clearly as possible.

ABOUT ASSIGN PROFILE

Bruce Fraser wrote in a previous Adobe forum:

(You could change profiles a thousand times via Assign Profile and the image would not degrade) "Inasmuch as the numbers in the file wouldn't change, this is true. But it would display incorrectly, and convert to any other space incorrectly, so it's fair to say that while the integrity of the data hasn't been compromised, and you can rescue the file by assigning the correct profile, for all practical purposes, it's hosed."

csullivan, 

      I do have a good understanding of Assign and Convert.




Not wanting to appear rude, condescending or disrespectful, but� like Marco, I really question the veracity of that statement. :/

      Conversions degrade color information...




I beg to differ. Conversions are necessary in order to create the best fit of an image with its intended output medium (a press or other). There is nothing "degraded" about a well-done conversion to the output color space -- quite the contrary.

Though it's true that, once converted, such a file is of limited usefulness for further conversions, for which it's far better to go back to the source image and start over.

      I like to keep my color conversions to an absolute minimum.




Well, I see no reason to convert more than just once, from source to intended output -- once for each output directly from the source.

Just as "G. Ballard" says re: "csullivan":

      if you know (and have Honored) the Source Space in Photoshop, WHY are
      you still talking about ASSIGNING a different profile to it � it is kind
      of a pointless experiment once you understand the point.




Exactly. What is the point, after converting, of assigning a profile that's different from the one that the file has been converted to?

Unless one is still unclear about the distinction...

      > I beg to differ (about Conversions degrade color information)...There
      is nothing "degraded" about a well-done conversion




Hmm... you may be right, Marco.

I recall I got that info in one of my forum discussions with Bruce Fraser or from one of his books, but I hope I am not misinforming people.

To a lay person (like me) who is trying to conceptual the theory that Converting a higher-gamut space like Adobe RGB to smaller-gamut spaces like a press CMYK or web sRGB space would have to clip or compress some colors � I guess that would be the basis of my point.

In any case, it is probably a good idea for most people to make as few profile Conversions as possible based on simple common sense principles like if we Convert AdobeRGB to sRGB -- and back again -- we have probably lost some color information that we can never get back.

How that theory may apply to the actual rocket science is over my pay grade and more likely suited to your technical expertise.

+++++++

BTW 

      > Converting to a profile changes the color numbers in the file, but keeps
      the appearance unchanged (except for gamut mismatches, in which case the
      rendering intent decides how the out-of-gamut colors in the source are
      mapped to the destination).




That totally rocks...

All,

The conversation has been great.

When one is part of a large industry such as graphic arts, you will deal with all kinds (those who are first time graphic designers, free lance operators, etc.)

Your assumptions are that each of these individuals will understand the dialog boxes which appear. What I was hoping was that I would be able to give a good explanation to those who are faced with such dialog boxes. I am never one to say "DO THIS BECAUSE." I am one who wants explain exactly what will happen if (you make the wrong choice)... and I have not come up with a very good example to explain TECHNICALLY what will happen if they choose to do such things (heck, many people have the ask check-boxes off in the color settings)

The prime example is having to deal with those who like to use the new features of just realeased software. The why of such "effects" don't output is just as important as why to do things a different way (Remember when Illustrator transparency first reared its ugly head?)

      >Unless one is still unclear about the distinction...in which case it's
      better to admit it.>>




You missed the point completely. Knowing and using the correct workflow and processes is a VERY, VERY small part of the equation. Understanding what happens when you don't is more important

      To a lay person (like me) who is trying to conceptualize the basic theory
      that Converting a higher-gamut space like Adobe RGB or ProPhotoRGB to
      smaller-gamut spaces like a press CMYK or web sRGB space would have to
      clip or compress or stir up some colors � I guess that would be the basis
      of my point.




Sure, perfectly reasonable. Yet, my point is that it is the very purpose of a conversion to optimize an images for its intended output.

At the same time, a converted image, specially one converted from an RGB space like or AdobeRGB or ProPhotoRGB, may well have undergone some substantial reduction of its color gamut (though not necessarily). That's why one should go back to the source file for further conversions to other color space destinations, in order to retain all the color gamut in the source that fits into any given destination.

It makes no sense, for example, to cut the source's gamut to SWOP and then convert that converted file to Sheetfed, only to lose some of the color brilliance that could have been retained in Sheetfed in a conversion made directly from the source image.

      That totally rocks...




That's very kind of you. Thanks.

      Knowing and using the correct workflow and processes is a VERY, VERY small
      part of the equation.




Definitely not. 

      Understanding what happens when you don't is more important.




How do you understand that if you don't understand what needs to happen so that things are done as intended?

Let me throw this into the mix. There is a case for assigning (false profile).

 <http://www.accessmylibrary.com/coms2/summary_0286-781223_ITM>

I found the whole article.

 <http://www.ledet.com/margulis/Makeready/MA48-Fate_and_False.pdf>

      I think it is best to read the author(s) whose writing style(s) you enjoy
      and can learn from...




If you want to be narrow minded and not learn anything new.

Look at what has happened with the big hoax of the last 10 years for example. I spite of all the factual historical and current evidence to the contrary there are some very narrow minded people that still believe it and vote politicians in who will stop at nothing to take our money and our liberties away based on that hoax.

I hate narrow minded people.

There's a big difference between having an open mind and having a hole in your head, DYP.

[Now editing my plonk list to include DYP on it.] Your comment has no place in these forums, DYP.

Same for you.

      If you want to be narrow minded and not learn anything new.




I don't see how such condescending statements advance any conversation. If you wish to be specific, be specific. Otherwise I would prefer to be spared the posturing and the stench of superiority.

      I was only pointing out uses for assigning a false profile (I don't know
      what better term to call it)




How about just "assigning a profile"? Anything wrong with using the terminology that everyone else uses?

You assign a profile, and, if it seems to fit, then it fits. If it doesn't, it doesn't. What is "false" about that?

If you are given a pair of shoes that are too small for your feet, are you going to put on "false shoes" that are the right size for your feet, or just the right shoes?

Well said, Marco.

Ok then lets call it assigning none correct profile.

I think you know exactly what I mean why nitpick about?

Because often times assigning a profile other than the one that came attached to the image is not the one that will finally fit. It's a means to a different end. Indeed it is a false profile. There's nothing wrong with calling it by a name that seems to make a lot of sense - false profile. The big objection it seems, is not the name, but the person who started calling it that.

DYP - I'm in your corner on this.

Amen, Peter! Let's forget the origin and focus on techniques that work. Let's build up, not tear down. There are lots of ways to achieve high quality results. Nobody has all the answers.

      The big objection it seems, is not the name, but the person who started
      calling it that.




It's the person (a mountebank) and the name.

It's "false" because someone somehow assigned the wrong profile to an image? How do you figure that the profile which makes the image look right is "false" and the one that a clueless operator ended up embedding, and makes the image look wrong, is "true" instead?

      I think you know exactly what I mean why nitpick about?




"Nitpick"? You are the one who insists on using a terminology that no one else uses. And gives no good reasons for its use either.

      There are lots of ways to achieve high quality results. Nobody has all
      the answers.




I view that as misplaced equanimity. There is such a thing as muddying up the water, after all, and spreading misleading notions like that of "false profiles".

If nobody has all the answers, those who talk such nonsense surely don't even have a few.

Sorry Marco, but to me it sounds like you just have some private vendetta against Margulis. Have you actually worked with some of his ideas or are you against them only because you don't like the man.

Most of the complaint I've read against Dan simply aren't true, especially if you've actually read the books. His techniques are completely compatible with modern color management. If fact, using both together makes you a better, more effective imager, but you'd actually have to open your mind to enjoy those benefits.

Yes, sure, it's all about me. Not about the substance of what I wrote.

Good job, Peter. Never mind that I tried to have an intelligent discussion.

You started out having an intelligent discourse but when it took a left turn into the intelligence went right.

More diversion. Well done, Peter. You do that very well, and intelligently.

Marco.

I, for one, have very much appreciated your comments and observations. Thank you.

I don't read or even see all the messages in this thread, as I do have a plonk list, but I do know at least one frequent contributor who revels at turning any discussion into a personal attack in the Photoshop Macintosh and Photography forum, then tries to accuse his interlocutor of doing exactly that. Transparent psychological projection, I suppose.

Since that contributor has the same first name you quote in #48, I guess that post may be directed at that person, who happens to idolize Margulis. (Yes, he's now plonked.)

Let me stress that I have absolutely nothing personal against Dan Margulis. In fact, I have seen him at conferences and in no way do I dislike the man. He even reminds me of several very good friends I have in Russia.

I do acknowledge that the man can be a magician at color correcting images for press printing, as I believe I have stated here too.

My beef with his teachings stems from the considerable damage done to me personally by his Professional Photoshop book at a point in my life where every minute counts in term of life expectancy.

Having strived to ameliorate that damage, I learned as much as I could about color management, so I fully understand why the true pros in the field of color management resent Mr. Margulis, and righfully so.

Marco,

Your post #51 is dated earlier than my #50. Hope you can still read it.

      I fully understand why the true pros in the field of color management
      resent Mr. Margulis, and righfully so.




I don't. At least not as much as I do you.

      I don't. At least not as much as I do you.




Oh, you are a color management pro? Nice.

      Oh, you are a color management pro? Nice.




I know, sorry I can't same the same about you.

      I know, sorry I can't same the same about you.




So sorry not to meet your provenly high standards.

So, at the cost of interrupting the oh-so enlightening banter by repeating myself -- one assigns a profile, and, if it seems to fit, then it fits. If it doesn't, it doesn't.

If you would deign to reply from the height of your lofty expertise, what is "false" about that?

Ok, we will assign a profile that doesn't fit to convert to a final profile to achieve what we want for the final result.

If you still don't understand that, you never will.

O intelligent one, nice dodge there, but you still haven't answered my question: what is "false" about the profile assigned to the image?

Seems to me the poster of #56 came up with that doesn't fit term. Maybe you would be better arguing with him about that.

Marco,

Call it whatever you want. A lot of people who use false profiles refer to them as such. If you're not comfortable with that term, that's fine too, but at this point the horse is quite beaten.

      A lot of people who use false profiles refer to them as such.




Try this and have a chuckle, please:
<http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&q=%22false+profile%22&start=20&sa=N>

Look at the first few entries, and see who actually uses "false-profile" terminology. First comes the meaning as applied to "false-profile oblique radiograph of the hip"! How 'bout that? Then you find "false profiles" of members of online communities.

The first 2 instances of "false profile" as applied to color management, which appear on the second page of results, are from...ColorTheory! How surprising.

"A lot of people" indeed...

The expression "self-referential" comes to mind.

      If you're not comfortable with that term, that's fine too, but at this
      point the horse is quite beaten.




It's really more like a dumb ass than a horse...

If you know how to do proper search you might actually learn something.

 <http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=8fT&q=%22false+profile%22+color+management&btnG=Search>

I also did a search for dumb ass, and the name Marco Ugolini came up. Sound familiar.

It's an echo chamber, my friend. Margulis invented the term, and others started repeating it, because, sadly, he is still influential. So your "proper search" finds instances of it most of which are related to...Margulis! Is that proving anything other than his influence?

Still, why is the profile "false"? As far as I'm concerned, a profile is either appropriate or inappropriate, based on the originator's expressed intention (if the profile is embedded) or the recipient's interpretation of the image (if no profile is embedded). There is nothing that makes any one profile inherently "true", therefore nothing that makes it inherently "false" either. It's all up to either honoring an existing workflow or expressing a preference.

As for your gratuitous insult, that says more about you than me, I'm afraid.

Ok, if you want to it inappropriate that is fine with me. I just hope you have now made up your mind what you want to call.

Me? I never had a doubt what not to call it, remember?