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Photo Forum / Digital Photography / Digital Photo / August 2006theis "embedded adobe rgb" thing,,,,,,
"embedded adobe rgb" who is this supposed to help....me or the printer? if there's one thing i've learned over the years dealing with printers, it's that no one gets it right. i've given them 4x5's with kodak color bars/grey scale. i've sent them RAW files. even FPO's with sample prints that i liked. they never get it right, and ultimately it requires a printer with a "good eye and color sense" anyway. so this "adobe rgb". does it guarantee anything? does it help me to quantify what i want? does it help the printer to be more faithful to what i want? a color reproduction in your brain is: a number of photons * spectral sensetivity of your eyes a spectral sensetivity is different for 40 times for a 1000 persons in test. a number of photons: 1. reflection light = a number of photons from radiation light * coeff of spectral reflection (paper and etc) 2. radiation light = a number of photons A color gamut is a all color visible to your eyes from the device. A gamut is limited by some math coordinates. All devices have a different gamut. That is impossible to reproduce exactly gamut of device by using another device. Adobe color gamut just little more in comparison with sRGB gamut. A printer gamut can be more different from both. http://www.terekhoff.com : "embedded adobe rgb" : who is this supposed to help....me or the printer? if there's one thing : i've learned over the years dealing with printers, it's that no one : gets it right. i've given them 4x5's with kodak color bars/grey scale. : i've sent them RAW files. even FPO's with sample prints that i liked. : they never get it right, and ultimately it requires a printer with a : "good eye and color sense" anyway. : so this "adobe rgb". does it guarantee anything? does it help me to : quantify what i want? does it help the printer to be more faithful to : what i want? The way I understand it, Adobe has taken the standard RGB and enhanced the standard. This was originally intended to be internal to their photo editing products. But some camera manufacturers realized that if their product would take advantage of that same format for better use with a major maker of high end photo editing they would have an advantage, at least until everyone did the same. :) As far as I can tell the aRGB format only works from the camera thru the adobe product. But since most printers do not have the ability to fully use the standard RGB format, they have no reason to include aRGB in their internal software. So aRGB has very little to do with the printing of your image. As to making a printer more "faithful" to what you want, this is a problem. Most home sized printers simply do not have the ability to accurately reproduce more than about half the colors available to the standard RGB format, if that many. There will always be some degree of variation between a monitor display and a print as there is always the problem of reflective vs additive color (light being colored by light bouncing off a surface vs light being colored by filters in the path of the light). Converting from one to the other is never completely exact. And if you have not calibrated your monitor and printer with a good calibrating device the variation between the two may be much larger. So aRGB will help effect the image from your camera to your adobe editing software and through the editing process. But will likely do little or nothing for your print process. At least this is how I understand it. others here may have more specific knowledge to help you. Randy ========== Randy Berbaum Champaign, IL A printer color space is a CMY or CMYK, there is no body here who can prove - what is better for current ink printed on current paper. If you care about color reproduction, try a different papers. Do a many prints of the same image - select what you like. As i sad, a color reproduction is a some shape bounded by match coordinates in color space. We just talking about nothing, you should see a gamut in 3D space for your printer and adobe rgb. Take a light box, select a light D50, take a monitor and compare. ICC profile not a cure. Gamut mapping from profile maker is a mix of true and mistakes. http://www.terekhoff.com > "embedded adobe rgb" > [quoted text clipped - 8 lines] > quantify what i want? does it help the printer to be more faithful to > what i want? No - it probably doesn't guarantee anything. If the printer is using a wet-process lab like a Fuji Frontier, there is very little (only saturated yellow) that is possible from the printer but outside sRGB colourspace yet inside aRGB colour space, so there is little to gain just from aRGB (unless you specialise in photos of daffodils?) As well as working in the same colourspace, then also you would need to edit and soft-proof with their printer profile embedded. This requires you to get everything right (monitor profile and your workflow) and for them to get things right (their profiles accurate, consistent operation/operators, fresh chemicals etc - you have to trust them) If you want to nail colour in your prints, then print your own on a higher end photo inkjet. Unfortunately, that does open up several other cans of worms... SNIP > so this "adobe rgb". does it guarantee anything? It is a colorspace that allows to render saturated colors more accurately, especially intended for process printing but useful with other printing technologies as well. > does it help me to quantify what i want? Not by itself. > does it help the printer to be more faithful to what i want? That depends on your combined skills in colormanagement.  SignatureBart > "embedded adobe rgb" > [quoted text clipped - 8 lines] > quantify what i want? does it help the printer to be more faithful to > what i want? This thread has so far been very informative about the existance of so many crackpot ideas relating to colour management. Adobe RGB is a Working Space Profile, it is one of many, and is supposed to have a colour Gamut similar to Inkjet Printers. sRGB is another Working Space Profile and is similar to the gamut of a Monitor. These Profiles are only part of Colour Management, and Device Profiles are also needed before any proper Colour Managed Workflow can be set up. Have a read at your Editing Program Help Files for Colour Management or ICC Profiles. If you can not find much info then that Program will not be able to use C.M. If you do not have a Colour Managed Workflow in place, then tagging Adobe RGB or sRGB or any other RGB onto your images is of no use whatsoever. Your Photo Lab will probably have a C. M. Workflow, and most of them use sRGB as their Workspace, simply because most of their work comes from P & S camera users, and most of those cameras only have sRGB. Roy G Roy, can you give us the next chapter? The one that explains what happens if we send Adobe RGB files to a mini lab. SignatureJoan http://www.flickr.com/photos/joan-in-manly : > "embedded adobe rgb" : > [quoted text clipped - 31 lines] : : Roy G >Joan wrote: > Roy, can you give us the next chapter? The one that explains what > happens if we send Adobe RGB files to a mini lab. I'm not Roy but here's what's going on ... the same color will have lower RGB values in a wider gamut working space than in a lower gamut space so if you print or display it ignoring the working space info then saturated colors look duller. To see this in action look at these three links (below) ... I took a RAW file image of a red bird and converted it three times, once in sRGB (smaller gamut), then AdobeRGB (mid-sized gamut), finally in ProPhoto (all visible light, so extremely wide gamut). The color "red" was approximately rendered as follows (R/G/B values) ... srgb 200/77/39 adobe rgb 158/53/0 prophoto rgb 144/86/46 In Photoshop or any other program that recognizes the profiles these all look pretty similar, but you can see what happens when you ignore the profiles by looking at the images in a non-color managed application like your web browser ... these three have been converted to jpegs without converting to sRGB first and you can see how dull the reds are in the prophoto rgb example ... http://members.aol.com/bhilton665/hilton_prophoto.jpg http://members.aol.com/bhilton665/hilton_adobergb.jpg http://members.aol.com/bhilton665/hilton_srgb.jpg If you download these and open in Photoshop and assign the correct working space to each of them you'll see that they suddenly look alike again. In other words "144/86/46" looks bright red when the program knows it's ProPhoto working space but dull red when the program ignores the working space info. So to answer your question "what happens if we send Adobe RGB files to a mini lab" look at the difference on your web browser between the sRGB and AdobeRGB versions and note how the saturated colors look duller. The fewer saturated colors you have the less you'll notice the differences. Bill > So to answer your question "what happens if we send Adobe RGB files to > a mini lab" look at the difference on your web browser between the sRGB > and AdobeRGB versions and note how the saturated colors look duller. > The fewer saturated colors you have the less you'll notice the > differences. Very nice explanation. Clear without unnecessary complexity. >> So to answer your question "what happens if we send Adobe RGB files to >> a mini lab" look at the difference on your web browser between the sRGB [quoted text clipped - 3 lines] > > Very nice explanation. Clear without unnecessary complexity. Except that if the lab uses a colour aware process, then it will make (almost) no difference whether your images are saved with aRGB or sRGB embedded. And if ASAAR is using a colour aware web browser (IE on a mac), then your example won't work. Some complexity is needed. >frederick wrote: > Except that if the lab uses a colour aware process, then it will make > (almost) no difference whether your images are saved with aRGB or sRGB > embedded. If the lab expects and assumes the images to be tagged with a certain space and you give them files in a different working space then it will indeed make a difference in how they appear. If the lab does the conversion for you then you're right, it won't matter, but the mini labs don't do this conversion (they assume sRGB) and the best custom labs actually give you a discount if you do it correctly yourself and convert to their device specific profile for their printer and paper (ie, you're no longer in an abstract working space). So it's always best to give them what they want. > And if ASAAR is using a colour aware web browser (IE on a mac), then > your example won't work. Actually the examples I gave DO work as I described because I stripped off the ICC profiles when I made the jpegs ... so there is no profile for your "colour aware web browser" to convert to, if you have one. > Some complexity is needed. It appears even the simple example I gave is too complex for some ... if you want the complex details read "Real World Color Management" ... Bill >> frederick wrote: >> Except that if the lab uses a colour aware process, then it will make [quoted text clipped - 23 lines] > It appears even the simple example I gave is too complex for some ... > if you want the complex details read "Real World Color Management" ... I assumed that your examples had embedded colour space profiles - I should have (done the obvious and) looked at them first... The original poster queried use of embedded aRGB - will it solve his colour consistency problems. The answer is no. Thanks Bill. I knew some of that, having read "Getting Colour Right" and knew it would be good to bring it out in a discussion. Call it a troll if you wish. :-) SignatureJoan http://www.flickr.com/photos/joan-in-manly : >Joan wrote: : > Roy, can you give us the next chapter? The one that explains what [quoted text clipped - 39 lines] : : Bill >>"embedded adobe rgb" >> [quoted text clipped - 11 lines] > This thread has so far been very informative about the existance of so many > crackpot ideas relating to colour management. Yes, I agree. > Adobe RGB is a Working Space Profile, it is one of many, and is supposed to > have a colour Gamut similar to Inkjet Printers. sRGB is another Working [quoted text clipped - 13 lines] > sRGB as their Workspace, simply because most of their work comes from P & S > camera users, and most of those cameras only have sRGB. A good photo lab will have ICC profiles for their printer, and you create image files with that profile applied. If you ask the lab for ICC profile for their printers, and they don't know what that is, find another lab. ;-) Color management: The main reason why we need color management is due to the way the eye responds to light. It is not linear and is not even independent of each channel. The eye actually subtracts one color from another to perceive some colors. You can't make the range of responses the eye sees with inks or CRTs, or LCDs without some special work. And even then the range the total range will almost always be lees that what can be p[perceived by the eye. Color management tries to correct issues and map colors that can't be reproduced into something close. The due to the spectral response of inks, colors may appear different depending on the light source, or two colors may appear the same but actually be different. Start here and read a little about the color spectrum. Ignore the eye sensitivity plots--in this page: they don't tell the whole story: http://www.midnightkite.com/color.html Next: Introduction to color science http://www.techmind.org/colour Note the double peak of the x-curve in the first figure--that peak in the blue is actually negative response, so the eye subtracts blue from the red channel, and that causes a lot of the issues and need for color management. The other reason is that if the inks don't perfectly match the spectral response of the eye, then the colors can't match the eye. No ink perfectly matches that response. So we have approximations. Out of Gamut: Getting a Handle on Color Management Color-geek extraordinaire Bruce Fraser spells out the basics in this primer on color management systems. http://www.creativepro.com/story/feature/13605.html Tons of info about color spaces: click on the "info" button and work from there. http://www.brucelindbloom.com/index.html This is also interesting: http://en.wikipedia.org/wiki/Purple Get the book: Real World Color Management 2nd edition, by Fraser et al., Peachpit Press, 2005. More good info: http://www.cs.unc.edu/~majumder/color/paper.html Here is my digital workflow which illustrates when color management steps are done: http://www.clarkvision.com/photoinfo/digitalworkflow Roger >>> "embedded adobe rgb" >>> [quoted text clipped - 92 lines] > > Roger And check out Bill Hilton's example! > A good photo lab will have ICC profiles for their printer, and you > create image files with that profile applied. If you ask the lab > for ICC profile for their printers, and they don't know what > that is, find another lab. ;-) I once asked a guy at the local Ritz Camera what kind of color space does their Fuji Frontier prefer? He said, "I think we usually use JPG." How did you control your mirth? SignatureJoan http://www.flickr.com/photos/joan-in-manly : > A good photo lab will have ICC profiles for their printer, and you : > create image files with that profile applied. If you ask the lab [quoted text clipped - 4 lines] : does their Fuji Frontier prefer? He said, "I think we usually use : JPG." > How did you control your mirth? > [quoted text clipped - 6 lines] > : does their Fuji Frontier prefer? He said, "I think we usually use > : JPG." That figures, nothing changes. I once handed in a slide film (E6) for processing at our local Camera shop, and knew I had problems when I was asked what size of Prints. When I explained, I was then told it would take 3 weeks to get it processed, because it was very complicated. I think I annoyed them when I said I could build a darkroom and process it myself quicker than that. I asked at PC World about the availability of ICC Profiles for their Photo Paper, was referred to the technician, who told me that they did not supply them because Photoshop would have all the Profiles it needed. Every profile for every paper in every printer?? Blank looks. Roy G > I asked at PC World about the availability of ICC Profiles for their Photo > Paper, was referred to the technician, who told me that they did not supply [quoted text clipped - 3 lines] > > Roy G What else would you expect with their fully(?) trained(?) staff. SignatureNeil Delete l to reply > "embedded adobe rgb" > [quoted text clipped - 8 lines] > quantify what i want? does it help the printer to be more faithful to > what i want? Excellent information Roger and Bill. Roger, your workflow is a bit light on details for those who don't already know about CM. (Monitor calibration, no double profiling). We all do it without any thought, but beginners need every step explained. I have produced one for my local Camera Club, it was written with complete novices in mind, and also for those who had crackpot versions. Go to www.ayrphoto.co.uk then to "Notices and Info" then to "How to print for accurate colour". It was designed for PCs and Epson Printers using Photoshop or Elements. But the principles can be applied to other systems. It does not cover profile conversion, before sending files to a Lab. If anyone thinks that is needed, I might have a go at adding another section, but I never use Labs. Roy G > > "embedded adobe rgb" > > [quoted text clipped - 29 lines] > > Roy G For a grouchy old Scotsman you're pretty knowledgeable SignatureWebfoot > For a grouchy old Scotsman you're pretty knowledgeable Do I detect an element of surprise in that response??? I do hope not !! > > For a grouchy old Scotsman you're pretty knowledgeable > > -- [quoted text clipped - 3 lines] > > I do hope not !!, Stereotypes, you know. In Grimsby, the common belief was that Scots were grouchy, stingy and none too bright. Of course, they thought the same about Geordies. Having gone to university in St. Andrews, I, of course, knew better. Not all Scots are grouchy. Signaturebill >> > For a grouchy old Scotsman you're pretty knowledgeable >> > -- [quoted text clipped - 8 lines] > same about Geordies. Having gone to university in St. Andrews, I, of > course, knew better. Not all Scots are grouchy. It is not the Grouchy bit that was worrying. You won't know, but until very recently we had a door mat with the wording "One nice person and one old Grump lives here". I did not buy it. It was just that you seemed a bit surprised about my depth of knowledge. St Andrews is viewed as an English University which just happens to be located within Scotland. Practically no Scots get in, and the Staff are nearly all English. Would any sensible Scots Undergrad want to spend 3 or 4 years in the wilderness of darkest Fife, surrounded by boring old foreign farts playing Golf. Even Dundee would be better than that, perhaps not a lot, but slightly better. Roy G > >> > For a grouchy old Scotsman you're pretty knowledgeable > >> > -- [quoted text clipped - 3 lines] > >> > >> I do hope not !!, I agree about St. Andrews. Why would anyone want to freeze 11.5 months a year for the dubious benefits of living in a tiny, unheated room with no hot water. I have to confess that I could get to smelling pretty ripe because taking a bath wasn't for the faint of heart. With respect to my growing awareness of your various areas of expertise that was just a gentle dig--I think I'm a latent troll always trying to dig up some shite. -- Bill in Lake Charles > > Stereotypes, you know. In Grimsby, the common belief was that Scots > > were grouchy, stingy and none too bright. Of course, they thought the [quoted text clipped - 20 lines] > > Roy G |
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