sRGB vs. Adobe RGB 1998

[ballroom_boy]

Hi Everyone!

I just purchased an iMac running OS 10.2.4 and I have been learning a lot about color management in order to get my Epson 870 printer to work properly (my old Windows 98 PC died a painful death and apparently Apple finally put decent print management in OS 10.2.x). I am a neophyte to color management and sometimes (OK, all of the time) get overwhelmed by the amount of information to be learned.

I have read that JPEGs produced by both the S1 and the S2 are in the sRGB colorspace. But in my reading, a lot of people talk about using Adobe 1998 RGB colorspace in Photoshop as it has a large gamut. I was told that sRGB is good if you do web only work - my work is 50% web based, 50% print.

I noticed when I open a JPEG in Photoshop and then change my working space to Adobe RGB 1998, the image on my display becomes "oversaturated" in appearance (skin tones get too warm, greens are more vibrant, etc) compared to working in sRGB. Is this normal? Same thing happens when I print (I use PostScript color management with an Intent of Relative Colormetric).

Would I be best to work in sRGB all of the time since I shoot mostly JPEGs? When should I use Adobe RGB 1998 as my workspace?

I am so confused...

Thanks
Roel :confused:

[davealan]

I also would like to add to this question. As you know, color “numbers” (Red Green Blue = 24/107/53 for instance) have no exact color representation until they are tied to a particular color space, i.e. sRGB 24/107/53 is one color, and Adobe 1998 24/107/53 is a slightly different color. There are many color spaces.

I have also heard the S2 produces files in the sRGB color space. I also would like exact confirmation on that. Why? Because a conflict exists. When I open any S2 file in PS7, it states that the file does not have an embedded color profile, and asks would I like to assign one. Then, for the S2 to be in the sRGB color space, it must be appropriate for a file to be assigned a particular color space BUT HAVE NO EMBEDDED COLOR PROFILE! Then, why is PS7 not smart enough to state, “this file is in sRGB, but no embedded color profile exists”? I suspect, perhaps, that the S2 has no color profile, just the color numbers “seen” by the CDD sensor’s red-blue-green color masks, and the file takes on a particular color space when one is assigned, via PS for instance. So, the point-blank question here is: Can a file be in a particular assigned color space WITHOUT an embedded color profile? If so, how? I thought the embedded color profile IS what assigns a particular color space.

I also wish to second my observations that Adobe 1998 color space is more saturated and vivid as compared to sRGB, both on screen and from a Fuji Frontier. Now THAT’S another mystery. I can convert a given file to sRGB, Adobe 1998 RGB, and Fuji Frontier ICC profile. They all look different on screen (of course). But the Fuji Frontier ICC profile results in PRINTS that are least vivid, sRGB more so, and Adobe 1998 even more so to the point of being overly saturated as compared to the actual scene. What’s wrong here? Everyone says to convert to the Fuji Frontier ICC Profile (or whatever machine you are printing on) before sending the files to the printer. Then why in my experience does the Fuji profile look least saturated, sRGB look more saturated (but I thought sRGB was an undesirably small color space), and Adobe 1998 color space looks knock-your socks off vivid? Same test picture files, sent to the same printer on the same day, just converted to the three mentioned color profiles in PS7. As far as I can see, I’d just send files to the Frontier in Adobe 1998 if I want vibrant-plus colors, or sRGB if I want slightly lesser vibrant colors, and I wouldn’t convert to the Frontier ICC at all.

Any thoughts to offer ??????


Dave

[apb]

http://super.nova.org/PhotoClass/PhotoClass07_05.html

For a good intro to color management, visit Chuck Gardner's online Photography Class, section 7. See the above link for some specific info on sRGB and Adobe RGB.

In order to understand and implement color management and the S2 (or any digital camera) you need:
1 - a calibrated monitor - using any of the 'puck' sensors but NOT the Adobe Gamma plugin or the apple built in calibration tool (your eye is not capable of calibrating your monitor).
2 - an understanding of why you are using color management.
3- understanding (from my point of view anyway) that a digital image is much closer to a C-41 neg than a E6 chrome. A digital file needs 'printing' (Levels, Curves and HSB adjustments) in order to look its best.


The way I understand S2 and color management is this (any corrections, discussion, better explanations are welcome ):

The camera always shoots a RAW file internally; if you have chosen to use JPEG or TIFF it converts on the fly internally. If you choose RAW (.raf) files, you get a straight dump of image data.

When you bring the JPEG files in, they are *tagged* with an sRGB profile. They are not *embedded* with that profile. Depending on how you set up color management in Photoshop, when you open the file in Photoshop, you can choose to ignore the sRGB tag, and open the file as unmanaged. This way you do not clip any data. If you accept the sRGB tag at this point, you will be stripping off color information.

Tagged Profiles means that the image data has not been converted. Embedded Profiles means that data has been converted.

sRGB is NOT the preferred or native color space of the S2. It IS the default color space for the S2's JPEGs and TIFFs. sRGB was created to provided a very small color space that would reproduce ok on many monitors and many systems.

If you bring in a JPEG or TIFF into photoshop, choose to ignore the sRGB tag, and open the file without color management, you can then *assign* a profile of Adobe98 (or whatever your standard working space is - Adobe98 is a universally accepted wide range profile).

RAW (.raf) files are different. You can process them with Converter EX or LE, or 3rd party solutions. I have not used any 3rd party solutions yet. If you choose LE you are not given any options, and the image ends up with (I think) an *embedded* sRGB profile. By using the EX , you have the choice of 16bit Adobe98, 16 bit FUJI (which I believe is an altered version of Adobe98) and sRGB. Since Adobe98 is my standard working space, I choose it.

In both situations however, you are losing color data by choosing Adobe98, since in both situations you are getting the max color information from the camera file. When choosing the Adobe98 colorspace, any information that may lie outside the Adobe98 space is clipped.



Camera Profiling:

You can use a camera profiling software (coloreyes 20/20 for example - http://www.integrated-color.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=CE2020) to create a custom profile for your camera.

In the JPEG process, you can choose to *convert* the raw (untagged, unprofiled) JPEG to the custom camera ICC profile to correct the colors, and then *assign* the image to the Adobe98 space (or your working color space). This takes advantage of the extra color information that may lie outside the Adobe98 space.

In the Converter EX process for RAW files lies a stumbling block. Fuji's EX software does not provide for the ability to process a true RAW file, or provide for the incorporation of a custom ICC profile to convert to. You can still process the file into Adobe98, and then use the custom camera profile to correct the hues. However you cannot take advantage of all the color info available in the unprocessed RAW (.raf) file.


hope this helps


andy

Adobe's Camera RAW plugin may handle this better, and there a few other programs like Bibble and Qimage that may work better too.

[cbandes]

So I took one of Will Crockett's seminars yesterday on using the S2 for portraiture. His color-management spiel was that sRGB is the preferred color space for S2 work.

(Now, he also did some weird and questionable things when getting an image ready for printing - converted into the print space instead of using the print dialogue or softproof, so I am a little skeptical about his color-mgt technique)

So my question for you guys - if not sRGB, then what? He was pretty persuasive on the question of whether or not AdobeRGB was the right choice (he says it's way too big) - FinePixRGB? Something else?

[apb]

sRGB is a small color space. The S2 is capable of capturing a colorspace greater than Adobe98. So why would you accept the sRGB as the 'correct' camera profile? I suspect it is because a majority of S2 users to be "prosumers", who may not be implementing color management correctly, if it all. Therefore if you use sRGB as your camera space, your images will look "OK" on most setups (as was the intent of creating sRGB).

sRGB does work for converting your images for web use. Also, my lab has a Frontier that uses sRGB as its native colorspace.

But why you would clip your images down into sRGB from the getgo is beyond me. I suspect that Will Crockett is speaking for FUJI. I am going to go and see this lecture myself - so we'll see what happens.

Andy


http://super.nova.org/PhotoClass/Part7/sRGBvAdobe2D.jpg

Adobe98 is in green. sRGB is in pink.



a couple of quotes from Chuck Gardner:

"Rather than adopt one of the existing RGB standards such as the de facto ColorMatch standard used in the graphic arts industry (i.e., 5000 K / 1.8 gamma) Microsoft and Hewlett-Packard instead created a new "Standard RGB" color space when ICC color management was incorporated into Windows 98. As the CIE Yzy diagram illustrates, the sRGB gamut (shown by the red outline) is slightly smaller than ColorMatch RGB. The big difference versus ColorMatch RGB is the default white point (6600 K vs 5000K) and gamma (2.2 vs 1.8). The sRGB gamut matches the color space of most uncalibrated scanners and monitors. "

"What is particularly significant about the Adobe RGB gamut is it is larger than a monitor can display. The reason why you might want to use an RGB color space which has colors you can't see on the screen becomes evident when you compare Adobe RGB and sRGB with the color space of a CYMK printer such as a large format HP DesignJet 3500 CP. It is easy to see from the three-dimensonal mapping of the color spaces that the larger Adobe RGB (1998) is nearly a perfect match to the CYMK colorspace of the printer.<http://super.nova.org/PhotoClass/Part7/ICC_3D/sRGB_AdobeRGB1998.html> You should also note that sRGB also fits within Adobe RGB color space. "

[apb]

I also suspect if you examine any other high end digital solution (other than DSLRs), you would not find Imacon (for example) using sRGB as its colorspace. Since the S2 is a "pro" camera, I'm not sure why they recommend a very unprofessional color space.


andy

[Tom V]

Thank you contributors to this thread. Keep the comments going. I am learning stuff with every post. Bring it on!

[apb]

http://www.shootsmarter.com/SMPworkflow.html

This is from Will Crockett's ShootSmarter website, in an article on color management:

..... Color space, or gamut, is nothing more than a container that holds all the colors and levels of gray of a digital photo file._ That's all.....Some color spaces are big, some small, but all are described in detail by a little packet of information called an ICC profile or a color tag._ We want you to realize that your digital camera (35mm SLR style) creates a file that fits inside a fairly small color space._ This color space is most accurately defined as an sRGB space._ If we were to describe the color space that your monitor can present on screen, it too would also be defined as sRGB._ Your Inkjet, dye sub or Pictrography printers and our professional digital printers are.. you guessed it -sRGB.
Because of this truth, we need to work only in the sRGB color space which means if your camera has a option (Nikon users particularly) of creating images in sRGB or Adobe RGB or any other space, always select the native sRGB space.
This will tell your camera to "build" its color information inside the sRBG color space and you will have no troubles getting the color you see on your properly calibrated monitor to match the colors of our StudioMaster Pro prints....

So in this context, sRGB is being pushed as it is the defacto color space for output on a pictography printer....

I am still looking for some proof of concept that the S2 delivers a much larger RAW colorspace. I attended a lecture given by Integrated Color Corp. [http://www.integrated-color.com] on their camera profiling software, which was demo'd using an S2. The presenter claims that most of the pro DSLR cameras capture a much wider color space than sRGB.

andy

[apb]

Brief update:

As far as my few tests have shown:

1. JPEG files can be brought into photoshop without color management, (ignoring sRGB), and assigned Adobe 98 for better color. The total amount of color information however is the same as sRGB.

2. RAW (.raf) files proccessed through Converter EX as a Adobe98 TIFF (16 bit converted to 8bit), FujiRGB (16 bit converted to 8bit), and sRGB 8bit all have the same amount of color information, regardless of profile.


Conclusions:
With the standard options, you cannot gain any more color information. You can (and I recommend) use Adobe98 as opposed to sRGB, as it is a much better working space, and I think has better color characteristics.

Processing .raf files into Adobe98 16bit is still the way to go for RAW files, as 16bit gives you much more color info to work with for doing Levels-Curves-HSB adjustments.

I need to try Adobe Camera Raw to see if it can pass through a truly RAW file. If it can, I will then profile the camera based on this true RAW file. I can then use a program like ColorThink (www.chromix.com) to compare the resulting custom profile for the camera, with know color spaces to see the actual amount of color information being generated by the S2.

Most of the color management pros I have spoken to agree that the S2 is capable of generating a far larger color gamut than sRGB.

The question remains how to get at it.


andy batt

PS talking to the FUJI tech support guys in Edison, supposedly FUJI Japan is releasing OSX version of S2 software in May.

[PaulN]

A few observations in no particular order:

1. sRGB is a 'small' color space. It was originally developed for TV/web, not print, so it only shows the colors a CRT will reproduce. If you're shooting mainly for web it works fine though.

2. The only difference between Adobe RGB and FinePix RGB is Adobe assumes a Windows gamma of 2.2 and the FinePix is calabrated to the Mac's gamma of 1.8.

3. It's true that the camera 'always shoots raw', but if you've selected TIFF or JPEG the flile is clipped to the sRGB color space. The raw file will always be clipped no matter what color space you convert to. To test this, you can convert the same file with a 1.5/2 stop difference in exposure and recover different data, especially in your shadows. That's why you want to especially avoid blowing out your highlights, if the file's a little dark you can recover shadow detail in processing.

4. The Fuji software, MacBibble, and Adobe Raw all correctly tag the files with the desired color space and Photoshop will see and use the tag. Depending on the color preferences you've selected you will use/discard/convert the file. You can also instruct Photoshop to warn you of mismatches and give you the option to choose.

5. There seems to be some confusion regarding assigning/converting a profile. When you assign a profile (Image>Mode>Assign Profile) you don't actually change the color numbers, all you're doing is telling Photoshop to 'translate' the colors from one space to another. When you convert a profile (Image>Mode>Convert to Profile) the program will actually convert the color numbers and you've changed the file.

6. The color space that's 'right' is the one that works best for you. The Fuji Frontier uses sRGB, and if you can load it's profile and use it when you're outputing to that printer that's great. The standard is Adobe RGB, or as it's sometimes called Adobe 1998. It has the widest color space of any except LAB, and that one is way too broad to use. There's no output device that comes close to using all the colors of that space. It's used by Photoshop and the system (either Mac or Windows) in their calabration and conversion algorighms though.

[Joe Peoples]

Though I convert from sRGB to Adobe 1998, I wonder how we're able to take advantage of the larger color space of Adobe 1998 when our S2 jpegs are shot in the smaller space of sRGB? I've been told by several people that colors can't be created when they're not in the original file...what's the real story???

[apb]

from what I have been able to determine, shooting with JPEG on the S2 does clip the colors within the sRGB color space. Choosing Adobe98 at this point instead of sRGB does 2 things: 1 visually it saturates the colors ; 2 it puts you into a standard working space that is more useful in a commercial environment.

An interesting comparison:

1 Shoot an jpeg with the s2.
2 save it to a folder on your computer
3 copy it, and change the name so one is titled sRGB and one is Adobe98
4 open both, and in the opening dialoge box assign the sRGB.jpg with a profile of sRGB (if it does not do this by default), and assign the Adobe98.jpg with the Adobe98 profile (thereby discarding the suggested sRGB profile the image was given by the camera).
5 confirm the color profiles of the images
6 go into the IMAGE menu, choose calculations
7 choose one image as the source 1, the other as source 2, choose the same color channel for both (green tends to have more information)
8 choose BLENDING mode as DIFFERENCE
9 choose new document and hit OK


you have now created a new image file that contains any information that is different between the two images. This image is most likely black, and has no information at all

I also tried this comparison with .RAF files that i processed with all three color profiles in Converter EX. Same conclusion - no difference in the color numbers for all three files.


the next trick is to shoot a controlled shot, in both JPEG and .RAF and compare those to see if .RAF is capturing more information. In theory the .RAF processed with Adobe98 ought to have more color information than the JPEG.



tune in next week for more!

andy

PS thank you to PaulN for the info - esp the clarifcation about assigning and converting profile information

[richard]

The best colour management, colour space website I have come across is the series of articles by Bruce Fraser at:
http://www.creativepro.com/author/home/40.html

In particular, the article on "Getting a handle on Colour Management" at:
http://www.creativepro.com/story/feature/13605.html

and very very relevent is the article "Finessing Photoshop Color" which, despite the title, actually discusses the actual differences between Adobe RGB and sRGB (and Bruce RGB) and the impact of using each - along with the pros and cons of wide and narrow colour spaces. VERY INTERESTING and has changed my way of working with S2 pics.

It is at: http://www.creativepro.com/story/feature/6541.html

And finally the article on "Exploring Wide Open Colour Spaces" at:
http://www.creativepro.com/story/feature/8582.html

Hope this helps

[apb]

Just a note of interest in the whole RAW capture and WB debate:

reading through Thom Hogan's CD/PDF version of his "Complete Guide to the FINEPIX S2 Pro" ->

1. he expresses a preference for grey cards over white cards

Quote, page 152:

"3. Place a neutral gray card so that it fills the image area (and is in the same light as you want to set the white balance for).

Note: Fuji recommends a white card, but most whites have colored pigments in them to whiten them, and it's harder to get a proper exposure on them, thus it's harder to get a proper exposure on them, thus it's harder to get a proper white balance. Use a Kodak neutral gray card instead."


2. he talks about the CCD chips ability to capture color info

Quote, page 91:

" RAF files contain exactly the data the Analog-to-Digital converter deciphered from the CCD. This is one reason why RAF files require special software to decode; the sensor data must be converted (interpolated/demosiaced) into RGB data and color corrected."


andy

[Bob L]

fascinating! and I actually understand bits of some of the posts. My problem is that 99% of my digital (and conventional) photography ends up in advertising/corporate brochures, mostly printed on 4-colour presses.

In the good old days, I just supplied the trannies and let everyone else mullah the reproduction! Now, with the majority of my images supplied as RGB files (JPEGs and or TIFFs) on disk, I have to take on more responsibilty for ensuring that my images are reproducible in print - I guess it's the same for all advertising photographers?

My question is this: does it matter what RGB space I work in (currently sRGB) and should I convert all my images to CMYK before supplying to the customer? And does this bring its own problems?

Simple answers would be extremely appreciated! Many thanks

BOB

[apb]

I deliver all my client files in Adobe98 RGB as TIFF - on the occasion I have to send via email, I JPEG at max quality. For all my paying jobs with the S2, I shoot raw, and convert to Adobe98 16bit. Adobe98 RGB *suppposedly* has the color gamut to cover the majority of conversions into CMYK. sRGB is a tiny color space best suited for web work.

CMYK color spaces tend to be pretty specialized and narrow - each press has its own profile (whether the press is actually profiled or not is another story). So its very hard to supply a CMYK "one size fits all" image. If you had to deliver CMYK, and are not given a target profile, the safest way to go is probably the "photoshop 5 CMYK" or "photoshop 4 CMYK" profile. Supplying either of these profiles will probably result in *OK* quality images, but will probably not look as good as they could.

I just learned of a service available - $15 a conversion at Color Centric (http://www.Colorcentric.com/) - I have not used them, however.

The problem of CMYK conversion, and why there are experts who do this, is that it is more than a 'hit the button' process. You have to know about ink limits, paper surfaces, individual press quirks, etc. Read the glossary entry here (http://www.colorcentric.com/help_glossary.asp#3) for more explanation.

Another complication is that many of your clients (designers, ADs, etc) are designing pieces that will go to multiple presses > the brochure is printed in boston, the pamphlet in NYC and the flyer in Houston> all on different presses that require different profiles - so if you convert to one, it may be wrong for the others.

In my small experience, I have found that many presshouses will not supply you with a profile. They say "just use the default CMYK". Sometimes this may be out of ignorance, or because the press is "old school", and does not use colorsync style color management. Sometimes, the press views it's profile as proprietary intellectual property & sometimes they just want the client to give them the original files so they can make money from the conversions.


Also complicating the issue, is whether or not the person you are handing the files to is color managed. A designer who has not setup photoshop/illustrator/quark/etc. for proper color management can completely screw up you carefully color managed workflow. If their monitor is not color profiled, they can 'correct' your image to make it look good on their monitor.

One solution offered is to submit all your RGB files in LAB space, as LAB is LAB - no profiles necessary. A client cannot screw up opening a LAB file. They can screw up converting a LAB file to CMYK the same way they can screw it up with RGB. Also, some layout programs offer sketchy support for LAB files.

It would be great if there was a CMYK equivalent of Adobe98 - a big enough CMYK space to ensure all presses had the color info they needed.

If you deal with a client that uses a specific printing house, you can try to build a working relationship with them, so that you are providing files that are optimized for their presses. I think that more and more presses are going to have to build open relationships with photographers, as more and more files are going to be digital originals, that will not be going through a pre-press or scan house.

ok that was long-winded.... hope it helps.... anyone who knows better, or has corrections, etc.. please post them....


cheers

andy batt

[apb]

just FYI

my current JPEG S2 workflow:

1. shoot at FINE JPEG setting (the max possible) - lesser settings clip and compress your color information.

2 open within photoshop, and choose "assign to sRGB" and then "convert to the working space (Adobe98)"

This seems to give the best color rendition, and keeps the colors from banding.
----------
I have also been using QP cards lately - a pad of them goes for 10$. They are small (camerabag friendly size) cards with neutral black, grey & white swatches. Pop one in a scene and you can set your histogram in photoshop to reflect your darkest black with detail (8,8,8), brightest white with detail (246,246,246) and your neutral gray clik balance. They also have a cross hair sharpness target on them - handy for checking focus

andy

[Bob L]

Thanks Andy.

I understand and agree with everything you say and certainly there is no "one size fits all" CMYK conversion.

I have a conversion profile "given" to me by one of my customers - a design/ad agency with a repro department, who know what they're about (not everyone does). Their advice is to supply CMYK files and the RGB files so whoever is dealing with the repro/print can use whichever they want. This means that I'm probably wasting my time converting for most customers, but one must do what one can!

I shoot on the S1, incidentally, so don't have the raw option - I will upgrade only when the "S3" comes to market, but that's a whole new set of posts!

As a parting shot, I do wonder just how much difference there is in reality between each colour space, especially given the CMYK conversion issues - we sometimes get a bit bogged down in the purist techno debate eg fine Jpeg vs TIFF vs RAW etc - I've done tests and there is little or no visible difference, even to me, so I'm sure the person seeing the images in the brochure/ad or whatever, completely bypasses this debate!

Still, you have to start somewhere and why aim low?

Thanks again Andy and everyone keep them coming - has anyone any info on the S3 by the way? (only joking)

Cheers

BOB L

[bjnicholls]

You're not seeing a difference between converted images because you're not soft proofing them. If you load the target profile for custom display proofing and click simulate paper white and black point, you'll see much more accurately what the target printer will deliver. Dot gain will vary a lot between presses and even more based on paper types. Try comparing an uncoated stock profile with a coated stock using soft proofing.

[easternherp]

If anyone is going to supply files for press printing then it is safer to turn colour management off in photoshop because if you don't have a profile for the press then colours can get messed up. It is best to supply a colour proof from your own printer and if you like the colour supply it to the people who will be printing it and allow them to convert it to match.
I work in a printers and Colour management is a very complicated subject. It seems that it should be easy but it aint. If you are serious then it is back to school for some major lessons. Ask the local printers if they can train you as they should know what they are doing.

[apb]

easternherp wrote: If anyone is going to supply files for press printing then it is safer to turn colour management off in photoshop because if you don't have a profile for the press then colours can get messed up

1- there is no way to turn off color management in photoshop 7.
2- if you don't color manage your images, you are going to mess up your color regardless.

It is best to supply a colour proof from your own printer and if you like the colour supply it to the people who will be printing it and allow them to convert it to match.


3- An epson printer, for example, printing RGB files, without being used as proofing device, can deliver colors that cannot possibly be matched on a CMYK press.

Colour management is a very complicated subject

4- absolutely. however if you are a professional photographer who is working in a digital environment, you either learn color management or you start shooting film again. Getting up to speed on basic color management is a lot easier than it used to be. You can, with a very small investment of time and money, color profile your monitor, printer and setup photoshop to work in a standard RGB color space (Adobe98 for example).

5- if don't have the time or technical inclination to deal with color management on your own, there a many good color consultants who will profile and setup your system for you. http://www.chromix.com for example.

6- once you understand the base RGB process you can move on to the CMYK side of things. This is an excellent thread over at Rob Galbraiths site -CMYK Color Management thread (http://www.robgalbraith.com/ubbthreads/showflat.php?Cat=&Board=UBB3&Number=161803&page=0&view=collapsed&sb=5&o=&fpart=1) . Some heavy hitters in digital photography have contributed to this thread - Jeff Schewe and Andrew Rodney for example


cheers

andy

[easternherp]

apb,

1- there is no way to turn off color management in photoshop 7.

Yes there is,

On a mac you can turn colour management off in the colours settings in the edit menu.

[apb]

easternherp...

i stand corrected... I just never noticed the setting to turn it off :-)

The Decription of this state is: "Color Management Off: preparation of content for video (on-screen presentations). Closely emulates the pre-color management behavior of an application"

It also sets your RGB space to the monitor space and CMYK to US Web Coated SWOP v2.

Let me restate that point by saying if you are turning off color management, you are not using photoshop to its full potential.


cheers

andy

[easternherp]

apb,

I work in a printers and find that many people have used colour management wrong.
If you do not have a cmyk profile for the printers you are going to use then it is best not to use a cmyk profile and leave the images as rgb and leave the printers to do the conversion. This way as long as your screen and personal printer are profiled and the colours match as close as possible then you should be ok.

[apb]

Easternherp...

I agree with you about using the wrong CMYK profile - choosing the wrong one to convert to, you lose valuable information.

As long as you have a color managed system that includes a profiled monitor, profiled printer and you use a standard RGB color space like Adobe98 or Colormatch you are pretty safe. Turning off RGB color management and not profiling your monitor is asking for trouble though :-)

have you dealt with cross rendered proofing? If you have a profiled printer, and a profile for a proofing device (for example a Kodak Approval) you can use your inkjet to create a simulation of a contract proof. That way you clip out any colors that a CMYK press would not be able to reproduce.

andy

[jeffinkansas]

I always use adobe rgb, but then convert to srgb for web because I have heard that some browsers actually pick up on this and then present the image correctly